The Streets Were Never Free. Congestion Pricing Finally Makes That Plain - <AUTHOR> https://www.nytimes.com/2019/04/04/upshot/the-streets-were-never-free-congestion-pricing-finally-makes-that-plain.html <comment><USER2> The streets were never free. We paid for it with our tax money. (Not to mention our 22 trillion dollar public debt)

I don't think people expect streets to be free in the same way you don't expect the police department to be free, the fire department to be free, public schools, etc.

In any case, my point is, we paid for the streets with our tax money and our debt, so don't masquerade this as some kind of "economic reckoning" where the people are FINALLY going to have to pay for those roads the government's been giving away for free for so long.

Because that's just not true.

<comment><USER3> > _don't masquerade this as some kind of "economic reckoning"_

In New York, low-income New Yorkers who own a car (or live in the zone) will be eligible for a waiver [1]. People with disabilities, too, will probably be eligible for a waiver. (Some carve-outs are still being pinned down.)

Taxis, Ubers, trucks and cars owned by people who opt to pay hundreds of dollars a month in parking are who will be taxed. Given the unusability of our streets, this seems closer to an economic reckoning than a political money grab.

(Crowded streets have all kinds of nasty externalities. I live in the zone. Crowded streets mean lots of honking at all hours of the day and night. It means the constant smell of brake pads at street level. When I look out of the window and see a stranded ambulance, it's a reminder of the risk my loved ones and I will face when the day comes when we need an ambulance. _Et cetera_.)

[1] [https://710wor.iheart.com/content/2019-04-01-congestion- pric...](https://710wor.iheart.com/content/2019-04-01-congestion-pricing- budget-approved-by-new-york-state/)

<comment><USER4> > Taxis, Ubers, trucks and cars owned by people who opt to pay hundreds of > dollars a month in parking are who will be taxed. Given the unusability of > our streets, this seems closer to an economic reckoning than a political > money grab.

Taxis and Ubers are forms of public transportation, and likely reduce the overall number of cars on the road. Simultaneously, they reduce the incidences of drunk driving, providing positive externalities.

Taxing trucks, used for transporting groceries, goods, and packages to the city, will increase the cost of each of these goods. The increase in grocery prices serves as a regressive tax on all people living within the congestion pricing zone.

The failings of the subway and train infrastructure are due to mismanagement on the part of the MTA and untenable, collectively bargained contracts. At the same time that driving within the city will become more expensive, these forms of transport have been reducing service within the city and to the surrounding regions while simultaneously increasing fares.

[0] [https://medium.com/@johnnyknocke/the-mta-loses-six- billion-d...](https://medium.com/@johnnyknocke/the-mta-loses-six-billion- dollars-a-year-and-nobody-cares-d0d23093b2d8)

[1] [https://www.stamfordadvocate.com/local/article/Cuts-to- Metro...](https://www.stamfordadvocate.com/local/article/Cuts-to-Metro-North- could-impact-more-than-12516146.php)

[2] [https://jalopnik.com/new-york-wont-shut-down-a-major- subway-...](https://jalopnik.com/new-york-wont-shut-down-a-major-subway-line- now-but-it-1831464730)

[3] [https://trid.trb.org/view/384171](https://trid.trb.org/view/384171)

<comment><USER5> > Taxis and Ubers are forms of public transportation, and likely reduce the > overall number of cars on the road.

This doesn't make sense to me.

IME - the vast majority of time there is a single customer or group in a taxi or uber. Assuming this is in fact the case. Taxis and ubers increase the number of trips taken by vehicle, but let's pretend in their favor that they leave that number flat. While they have a passenger in them they are trading 1-1 for a private vehicle to a "public" vehicle. While they don't have a passenger in them they are trading 0-1 for private vehicles to "public" vehicles. That results in a net increase in vehicles.

<comment><USER6> It lessens the amount of car storage needed too, though, which is also important. It would be nice if multi-person trips like UberPool would be exempted to encourage their use, but I don't know if that's technically feasible.

<comment><USER7> It lessens the amount of cars storage and increases the amount of cars on the road.

You can't transport by car and reduce both at the same time!

<comment><USER8> Fewer overall cars because fewer people own cars due to taxis and uber and Higher utilization of the cars that do exist because a higher % of cars are taxis and ubers

Some combination of these two factors could mean that there are fewer cars idle at any time ("storage") and more cars in service at any time. I'm not necessarily saying that's what is happening but it's definitely possible.

Looking into the future, a great outcome of driverless cars would be the commoditization of car transport. You essentially say where you're going and whether you are willing to share the ride. A driverless car pops off the queue to pick you up, or a multi-person car slightly diverts from its route to pick up up (a la Uber Pool).

\- Each physical car sees much higher utilization, allowing fewer cars to exist overall and parking space needs are reduced.

\- A large network of efficient driverless cars means it's more likely you can get a shared ride quickly and with minimal diversion from everyone's route. Ideally an improved shared ride experience would result in higher usage of shared rides, meaning that fewer cars need to be on the road at any given time = lower pollution and congestion.

<comment><USER9> > Fewer overall cars

Fewer cars, but more miles. Every moment that a car is going between one drop- off and the next pick-up adds to the total.

> Each physical car sees much higher utilization

Higher utilization is a mixed blessing. The more a car is driven per day, the fewer days it will be until replacement. There's not much difference between two cars each being driven half the time all year and two cars each being driven all the time half the year. At best you get some benefit from keeping the car warmed up, but that's outweighed by the passenger-less miles.

> t's more likely you can get a shared ride quickly and with minimal diversion

That would work a lot better if demand were uniformly distributed, but in fact it's highly cyclic - toward office areas in the morning, away from them in the evening. This asymmetry is even worse for things like sporting events. Once a driver has taken a commuter to work, going anywhere else means 2x distance because they'll have to come back for the matching commute home.

The only way to reduce ecological footprint is to reduce the number of vehicle miles per person. It doesn't matter who or what is driving the vehicle. Reducing commute distance works, even when people are still in cars but especially when people can walk/bike instead. Increasing per-vehicle occupancy helps, whether it's car pooling or mass transit. Replacing private cars with shared ones doesn't make a dent, and in some cases can make things worse.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER10> I post something like this every time the congestion pricing subject comes up. We have congestion pricing in Minneapolis / St Paul and it just works. If I'm in a hurry, I have the option to choose to use the priced lane. We're rolling it out to all of the major highways (it's on 3 of them so far). I wish we had it on more lanes on all highways already, because what is the point of having a 60mph road if most of the time you are barely going 20mph, or trip lengths are otherwise completely unpredictable? It's also particularly important to people who might have to travel to multiple jobs, or people with children in school/day care, when consistency in travel time is extremely valuable to them.

There is a concept in economics called spontaneous order. Once the cost of congestion becomes apparent through the price mechanism, then society can reconfigure itself to adapt to it. You just have to have the price mechanism in place to signal it. People will figure it out and adapt once you have implemented congestion pricing. Practically every medium size or larger city in America has terrible traffic congestion problems.

Importantly, you have to resist the temptation to set a price ceiling (like Houston did at $8), as it will not work effectively because it will not allow the price mechanism to work and will cause a shortage of road capacity and you end up with no material change and basically a bad tax. (E.g., the true cost of congestion spurs demand for apartments and transit options near the city center, which in turn reduces traffic congestion.) Also important that it is purely congestion pricing and not resulting in crony government. Changes in laws and zoning and public transit will occur subsequently.

I am excited for NYC to pilot this and hope it becomes a success for that city.

<comment><USER11> "We have congestion pricing in Minneapolis / St Paul and it just works. We're rolling it out to all of the major highways."

Aren't these two very different things ?

I own a home in MPLS and I don't know anything about congestion pricing there. I _think_ you must be talking about the lane restrictions on the freeways ?

Congestion pricing, as it is in London, and as is being discussed for NYC, is the concept of the city center being an island of paid entrance. As if you could not enter downtown MPLS without paying a fee.

I don't have any comment on your broad, economic analysis - just that the lane restrictions on 35 are really not the same thing as the congestion pricing being discussed here...

<comment><USER12> He's probably talking about the HOV lanes on 35W and 394. Which aren't even remotely the same as what is being proposed for manhattan.

</comment></comment></comment><comment><USER13> When I worked in a major city I would go on a half-joke rant anytime someone brought up traffic, parking,or obesity. If I were somehow the king of a major city, I would have a giant parking lot on the outside, and ban all cars. You could buy day passes if you need access to the roads to move or something, but it would be discouraged. People would walk more, and be healthier, The air would be higher quality, and most importantly you wouldn't have to wait to cross the street when you're walking to lunch.

<comment><USER14> Also, there wouldn't be many lunch options because delivery services wouldn't be able to use cars and trucks.

<comment><USER15> So restaurants, bars, and taverns didn't exist until after the automobile was invented. Got it!

<comment><USER16> I think this comment deserves a Michelin Star!

[https://en.wikipedia.org/wiki/Michelin_Guide](https://en.wikipedia.org/wiki/Michelin_Guide)

Hint: Why would a tire company put out a restaurant guidebook?

</comment></comment></comment></comment><comment><USER17> It's sad to see congestion pricing in America. I had hoped that the long-lived cultural freedom of driving would keep it at bay for longer, but I guess not anymore.

I live in Sydney. It takes a 45 minute drive to visit a family member, who is sick and homebound. To do so in the shortest and least congested route, I must pay 3 tolls: $14.85 total, one way; $30 dollars a trip.

Public transport is not a suitable option. Instead of 45 minutes one way, the combined trip time balloons to 2 hours (4 hours to and back) due to poor proximity to train stations, and bus connections that require waiting.

Every time I drive, I feel less free to move around my city. I feel less free to visit my friends and family. 'Freedom of movement' isn't some crazy lunatic idea. It is an important part of living for many people.

<comment><USER18> Your freedom to drive where ever you choose on the fastest route infringes on freedoms of others, for example:

* their freedom to drive on the fastest route possible * their freedom not to have a large road in front of their home * their freedom not to have their taxes invested in a road infrastructure ballooned to a level that they might not need * their freedom to live in a world that is not inflicted by global warming

Freedom to move does not mean you can do so at any cost to the freedom of others.

<comment><USER13> I don't think your examples really count as freedoms. I agree with your point, but I don't think you need to stretch the definition of a word to make it.

<comment><USER19> But how is the right to drive anywhere more of a freedom than those other things?

<comment><USER13> Because it is told from the perspective of the activity that is allowed. Now they could have technically been stated as the freedom from {Annoying/Harmful thing}* but thats still weak. The only reason to it is to take away power from the original argument by watering down the language it used. I'm sure the op didn't mean anything by it, I just happened to be listening to a conference call with a lot of corporate speak and was particular sensitive to how words are (mis)used

The actual point is that freedoms _should_ be curtailed when they cause harm to others.

In this case unchecked freedom of movement can cause harm to society in different ways, so some forms of movement are restricted. Which is already true, we have signs, lights walls, fences, licenses, etc to restrict our movement. So the argument is really about how much more should they be restricted.

* EDIT, Zarath already called me out on that, but I still think it's a stretch

</comment></comment></comment></comment></comment><comment><USER20> As a NYC resident for 11 years now I see this as a necessary transition. The streets aren't getting any wider unless we do away with street parking. I don't hear anyone rushing to suggest that option, although it's easy to forget there was a time when the streets weren't lined with cars - but horse shit. So we trade one inconvenience for a slightly less inconvenient sight (I own and park my car on the street dealing with the inconvenience of alternate side parking twice weekly). The focus really needs to be on improving the efficiency of the MTA, reducing distance between trains with more efficient switching is big part of that. The inefficiencies of the trains and improved efficiencies of app based rideshare dispatch is what is pulling ridership from the trains the most.

</comment><comment><USER21> I think Emily Badger sort of misses the point. A scarcity tax is completely different from a user benefit fee for road maintenance. For public goods, it's a _good_ thing for the government to subsidize the fixed costs of the public good. But where there is traffic, the road is not entirely a public good anymore and we are already paying the cost of congestion, but the price is in the form of time and inconvenience rather than dollars. A congestion charge converts the time price into a monetary price. It makes sense to charge a congestion charge because it is merely harnessing a price that drivers already pay and using it to improve the city.

The same is true for land value taxes. Tenants pay the scarcity price for land anyway (in the form of land rent) regardless of the level of tax, so the government might as well harness that energy and use it to benefit all the people instead of a few.

<comment><USER22> This assumes that either:

1\. People can arbitrarily convert time into money, ie, there's not a reason they'd prefer to pay some expenses in time.

2\. People are free to change their travel times, and aren't being coerced into traveling at a particular time. If travel time is a monopsony, then this is mere rent extraction because people can't adjust behavior in response to economic pressures.

<comment><USER21> Yes, and in my opinion those are both valid assumptions to make.

1\. You're right, congestion pricing forces drivers to reveal the marginal price for time. In a congested road, what makes the marginal driver decide not to drive at a specific time? Because he knows that it will take too much time due to traffic (or because he is simply forced to queue). In a toll road, what makes the marginal driver decide not to drive at a given time? Because he knows it will cost too much money. At the margin, congestion pricing turns a time cost into a monetary cost.

For those individuals whose value of time is lower than the marginal driver (i.e., people who would rather have a traffic jam than pay the toll), congestion pricing itself can make them worse off, but when the proceeds are reinvested in transit I think it's probable that congestion pricing will generally benefit lower-income people.

2\. Congested roads _already_ force people to change their travel time. If you try to cross a congested bridge at a specific time, you will be queued until all the people in front of you have passed. So I suppose you could say the road already is extracting rent and throwing it away. Congestion pricing harnesses the value (of all the drivers whose value of time is _above_ the marginal driver) instead of discarding it.

<comment><USER22> I'm not sure I follow your argument on 2.

If people aren't free to adjust their driving habits, congestion pricing merely raises the cost for them, because the time to commute doesn't go down (appreciably) — everyone is still on the road at the same time.

It then effectively becomes a regressive tax: those least free to change their schedule are those in the lowest earning jobs, and hence those most coerced to pay the cost.

I'm not sure I believe that's an effective way to raise money for government.

<comment><USER21> I disagree with your premise. There _are_ people on the margin who decide to drive or not because of the traffic (or who are forced to queue unexpectedly). If the roads and parking garages had infinite capacity, then there would be hundreds of thousands more cars on the road in Manhattan. It's implausible that all the people who remain on the road today are purely inelastic.

I also disagree that the tax would be incident on those with the lowest paying jobs. Higher-paying workers are more likely to pay more, since people with price-inelastic demand for driving are more likely to be those who value their time more highly.

Finally, I don't think the primary purpose is to raise money for the government, but instead to manage the road resource so that the throughput is high.

<comment><USER22> That decreasing the price causes elastic demand doesn't indicate that raise the price decreases demand elastically: there can be a largely inelastic base load.

> Higher-paying workers are more likely to pay more, since people with price- > inelastic demand for driving are more likely to be those who value their > time more highly.

Again, this is only true absent coercive forces —

Higher paid workers (on average) also have more schedule flexibility and ability to use money to cover for their physical absence.

By contrast, lower paid workers have less flexible schedules and a greater need to utilize their time — eg, they have to perform childcare because their market rate per hour is below child care services.

This leads to a situation where high paid workers have more elastic price demand than low paid workers, and raising prices ends up charging low paid workers because if market distortions from other factors.

</comment></comment></comment></comment></comment></comment><comment><USER23> All markets have congestion controls, they're called prices. The only reason roads and traffic don't function well is because they don't have prices. Traffic on roads* is the 21st equivalent of Soviet breadlines.

*(particularly in the US where they are cross subsidized the most)

<comment><USER24> Wow, I never thought of it that way, but it's a great point.

</comment></comment><comment><USER25> We already have a kind of congestion pricing, in some sense. If you plan a trip during peak hours, it costs you more time. It's pretty typical, then, to plan leisure trips into or out of the city based around when traffic will be light.

It's just that this cost in time isn't distributed nearly as ideally as it could be. It costs an individual the same amount whether they take a bus or a car with four people or four cars with one person each. If we tax per-vehicle instead, that pushes people not only to shape their travel times more ideally, but to also use more efficient forms of transportation.

So long as this is used as a means to shape travel to be more efficient and not just as a way to gobble up revenue, it might be alright. I think toll bridges/roads are mostly this way, where they're free in the dead of night when few are on the roads, so I'm hopeful.

<comment><USER26> > "We already have a kind of congestion pricing, in some sense. If you plan a > trip during peak hours, it costs you more time."

this is an underappreciated point, as it underlies the popularity of congestion pricing among wealthier folks, whatever their politics (left- leaners ostensibly would otherwise support more egalitarian/progressive policies).

currently everyone pays with their time, whether rich or poor. you can't buy your way out of the problem just for yourself. irksomely, money is of no advantage. but with congestion pricing, you could, and that's really appealing to wealthy folks.

i'm not arguing against congestion pricing, just noting a less-visible motivation. a progressive pricing scheme (pay more if you have higher income/net worth), for example, would still reduce congestion while providing more egalitarian access.

</comment></comment><comment><USER27> The thing that this article doesn't discuss is the fact that Uber spent $2M on lobbying to help push through congestion pricing. [0]

>"Over the past several years, we've been proud to work with a diverse coalition to fight for comprehensive congestion pricing, and we're excited to see Albany take action to reduce congestion and invest in mass transit," said Harry Hartfeld, an Uber spokesman.

>Roughly $1 million went to some of the top city lobbyists, including Stu Loeser, a onetime senior aide to former Mayor Mike Bloomberg.

>Another $700,000 went to fund the Fix Our Transit coalition's ad campaign that targeted undecided Albany politicians.

[0] [https://nypost.com/2019/04/03/uber-spent-2m-to-help-push- thr...](https://nypost.com/2019/04/03/uber-spent-2m-to-help-push-through- congestion-pricing/)

</comment><comment><USER28> It's weird to see someone calling roads free when I give the government 25% of my paycheck every month to pay for things like roads.

We can't even pass a tax in my town to give necessary funds for road repairs beyond the most basic. I wonder how something like that would fair.

<comment><USER29> Yes but that 25% is for social security and the bloated healthcare system, roads are extra.

</comment></comment><comment><USER30> Traffic itself is a symptom of roads being free in the first place. Charge drivers exactly what it costs to maintain them plus a small profit and suddenly there will be little traffic and no major potholes. Taxpayers will get all that money back too, and they can either spend it on driving fees or they can save the money if they use roads less.

</comment><comment><USER31> I wonder if we (as a society) in the not too distant future can make driving embarrassing?

My hope is that if someone sits alone in their big SUV stuck in traffic, pedestrians, cyclists and others will look at that person disparagingly. Like how people look at dog owners not picking up their dogs feces, cigarette smokers or how they look at obese people buying ice cream... Or how hypochondriacs who go to the doctor when they don't need to are shamed in countries with socialized health care.

Maybe it is not nice to use shame as a weapon, but it is a powerful one. We have about ten years to completely change how our societies work before it is to late. All options should be on the table.

<comment><USER32> Shame me all you want, I'm not biking my commute in 90/20 degree weather with a backpack full of stuff including a laptop and no reasonable way to listen to music when I have such a comfortable SUV-type car.

<comment> crooked-v This is the whole reason congestion charges exist: to get people to weigh comfort and laziness against personal cost.

> no reasonable way to listen to music

...headphones?

<comment><USER32> Listening to headphones while bicycling isn't safe, and playing it from a speaker where everyone around you will hear it feels rude.

<comment><USER33> Trekz Titanium. Or any other brand of bone conduction headphone. They sound quite good for the price and the fact that I can hear everything else around me at full volume.

</comment></comment></comment></comment></comment><comment><USER34> I'm disappointed that motorcycles/scooters and lane splitting aren't brought into the conversation more when discussions about traffic congestion come up. It feels like a win/win for nearly everyone to promote two wheeled transportation and allow them to split lanes or filter through traffic. Those who do not want to ever ride on two wheels still get the benefit of others doing so and essentially taking themselves out of the traffic queue. There's also been studies about how allowing lane splitting/filtering are ultimately safer for the riders too.

<comment><USER35> Do you have links to some of these studies? Asking as a motorcyclist...

<comment><USER34> The study that I remember off the top of my head is the one that came out of UC Berkeley. News article: [https://news.berkeley.edu/2015/05/29/motorcycle- lanesplittin...](https://news.berkeley.edu/2015/05/29/motorcycle- lanesplitting-report/)

There's been a couple of others that I remember seeing, but I don't remember them or which sources I saw them at.

</comment></comment></comment><comment><USER36> This will be absolutely necessary when cars are self-driving. Instead of parking they will just drift around the block when you buy something for example. Also there will be empty Uber cars drifting around to be close if somebody needs it. On top you won't worry so much about traffic if you can sleep in you car or do something else.

Driving was always limited by the costs of somebody sitting behind the wheel. Look how congested many cities of third world countries are, low labor costs for cab drivers are a factor there.

<comment><USER37> I think midtown manhattan is a pretty good example of what self driving cars will look like. Most of the vehicles are taxis, ride shares, or delivery trucks. Very few of them ever park longer than to drop something off.

</comment></comment><comment><USER38> A few comments have mentioned different levels or road damage caused by different vehicles, with heavier vehicles causing more damage.

How much does tire pressure matter in that? If two vehicles have the same weight and number of tires taking the load, evenly distributed among the tires, but one of them runs with higher tire pressure, it will have a proportionately smaller contact area, and so a proportionately higher ground pressure.

In general, a tire supporting weight W at pressure P will have a contact area A such that P x A = W.

I'd expect total road damage to depend on both area and pressure. Pressure would determine whether you are going to damage the surface, and area would determine how big an area will damaged.

For causing cracks that lead to potholes, I'm not sure area matters as much as the pressure, so am curious about lighter vehicles with high pressure tires.

My car has a pressure of 32 psi. Back when I was a regular bike commuter [1] my bike had a pressure of 110 psi.

Wikipedia has a nice table of the ground pressure of several things [2]. Some excerpts, in psi:

        4  Diedrich D-50 T2 drilling rig
        8  Human male
       15  M1 Abrams tank
       25  1993 Toyota 4Runner
       25  Adult horse
       30  Passenger car
       40  Mountain bike
       90  Road racing bike
      470  Stiletto heel

A bit of Googling suggests delivery trucks are between 85 and 110 psi for most fleets, and around 110 seems to be normal for big rig trucks, too.

So...trucks being more damaging than cars is quite believable. More interesting is different kinds of passenger cars. Honda's recommended tire pressure for a Civic and a CR-V, e.g., are largely the same range. Does this mean a CR-V is not much more damaging than a Civic?

And where do bikes with high psi fit in? The have the pressure of a delivery truck, but have a much smaller contact area. Is there some minimal area needed before even high pressure damages the road, so bikes are OK? Or is it just that because the areas is smaller it takes longer to cause enough cumulative damage for people in cars to notice?

[1] when I lived in flat Cupertino. That died when I move to Seattle and found that fat people on bikes don't get along well with hills.

[2] [https://en.wikipedia.org/wiki/Ground_pressure](https://en.wikipedia.org/wiki/Ground_pressure)

<comment><USER39> It seems to me like road damage involves processes that happen deeper, for example those that create tire ruts in the lane. I'd guess the area should be counted as larger the deeper you go.

It seems plausible to me that if you drove trucks over an unlined parking lot completely randomly, then it would last much longer than when you run the same trucks on a highway lane.

</comment></comment><comment><USER40> I think about this a lot when considering China's extensive High-Speed Rail network. China's government operates it at a loss, and the capital expense must have been enormous, even with their wages. But the government had enough social good and political reasons to bite the cost.

The USA and our interstate system are the same way. The cost was enormous, the maintenance burden continues to outpace the money we make on gas tax and registration, yet we had political and social good reasons for building it. The interstate was a massive investment, and investments of similar scale could give us a HSR network at least on major corridors. But for some reason, we have a social good attitude towards highways and a social waste attitude towards subsidizing rail.

</comment><comment><USER41> I am impressed with the good title. Article speaks to unspoken history of purposefully hidden transportation costs that promote car sales and urban sprawl to this day. Bring back the electric streetcar

<comment><USER32> I think we have something great here where you can travel nice countryside settings in a car and it would be a terrible shame to give that up or price the poor out of it.

</comment></comment><comment><USER42> I mean infrastructure is what everyone points to when one asks "what am I even paying taxes for?" Often even the short hand of "roads".

<comment><USER43> Police, fire departments, emergency services, public transportation, ..

<comment><USER44> While I agree these are services people pay taxes for, Police mostly target the poor, fire departments are stationed closest to the wealthier neighborhoods, emergency services are generally better in wealthier areas, and public transportation in most of the US is generally poor, airline travel being the only thing worse. It's hard to convince someone who isn't of means that raising taxes on them is somehow of benefit to them. We'd be far better forcing companies to pay and freeing up the market for more people to work from home. That would actually solve the congestion issues without punishing the people who can't afford it.

</comment></comment></comment><comment><USER45> In Tokyo, there is no congestion pricing, but instead there is a ban on larger trucks loading/unloading during many hours of the day. Everyone from the businesses to the truckers and retail workers tolerate it and work night shifts (often without overtime) because the culture (for better or worse) emphasizes the needs of society over the individual.

Would such a policy work well if brought over to the states? Given the amount of tangentially connected regulations and special interests such a strict ban may just increase prices and make things worse.

</comment><comment><USER46> > Local laws require off-street parking from businesses and housing > developers, who pass on the construction cost of it to tenants and customers > who may not drive at all.

I'd love to see the tenents stay in business with a dirt road out front. Or a pasture that no cars can pass through.

They're not doing us any favors. They're keeping themselves in business.

</comment><comment><USER47> A wild idea already decades past it's prime:

in addition to the odometer, include a chronometer: something like "hours driving above 5mph". Then tax on a combination of those.

That seems like it would have been be able to implicitly price congestion into a progressive use-based tax.

</comment><comment><USER48> Congestion does not necessarily mean a shortage of roads. Sometimes roads make congestion worse. Braess' Paradox has shown to occur as often as not.

</comment><comment><USER49> This is all kinds of wrong, the problem could be tackled much better, for example most companies have no incentives to hire workers near their premises (or relocating them to make it so), meaning they get no benefit if they emplooyes have a 10 minute commute over a 2 hour commute; car companies have no incentive to build smaller cars, small single-person cars should be far more common but instead we are stuck with hundreads of people buying the biggest car they can get a loan for.

<comment><USER50> That doesn't really seem true to me. Car companies make products that can sell. People vote with their feet. People make decisions to buy bigger vehicles so that's what is manufactured. If there is increased demand for compact cars the manufacturers will make more (like they do outside of the US). Companies might not seek to hire people nearby but they might put their offices in a more convenient location. Either way you seem to completely miss the idea that alternative methods of transportation like mass transit or bicycles etc might expand in use. Which can cause those things to expand (better mass transit coverage, better and more protected bike paths). Again there are examples all over the world outside of the US.

<comment><USER49> > People vote with their feet. People make decisions to buy bigger vehicles so > that's what is manufactured. If there is increased demand for compact cars > the manufacturers will make more (like they do outside of the US)

Yeah and people are irrational and wrong, that's why the right incentives must exist so they are more incentived to buy smaller cars such as single-person or 2 person cars.

> Either way you seem to completely miss the idea that alternative methods of > transportation like mass transit

I did not, of course better transportation its the solution in long term but in the short one we need viable solutions as well.

</comment></comment></comment><comment><USER51> This is understandable for high density urban areas but makes no sense for most of the country.

</comment><comment><USER52> Congestion pricing is an admission that the fuel taxes are being used for other purposes than roads.

<comment><USER53> or that the taxes are far too low to support the cost of road maintainance

<comment><USER54> New York's problem is that its fuel consumption has been flat for 50 years because of increasing fuel efficiency and low population growth. Meanwhile, everything else is more expensive to maintain so it must make up the difference with other funding sources or higher taxes. The latter is is difficult political issue when they are already near the top for state fuel taxation.

</comment></comment></comment><comment><USER55> It's interesting that Americans (as we see in most of the comments) feel so entitled to let taxes pay for their right to take their car everywhere, but feel so strongly against having taxes pay for universal healthcare.

In Europe, we do the opposite.</comment>


How I Raised $55M Of Venture Capital In Two Months - <AUTHOR> http://roachpost.com/2010/02/16/how-i-raised-55-million-of-venture-capital-in-two-months/

<comment><USER2> "you can do it too" should be rephrased as "you can do it too if you have my kind of connections". Good advice for hustling things along, but only if you are already solidly "in the game".

</comment><comment><USER3> Not quite sure when he joined elance but with big names like John Doerr and Ram Shriram behind him already - the post is hardly surprising.

I'd love to hear how someone with lesser traction or brand name VCs raised cash and how it took them 10 months.

</comment><comment><USER4> _While I was blabbing on and on about whether we should take more, or from whom we should include in the round, Bill said, "Take the (blank) money." From that day, I have advised the same to every company I've since worked with._

I'm not sure that this is great advice. If you don't have a conceivable use for the money taking too much could kill you thanks to the expectations that are attached to said finance.</comment>


Stickam Owned By Porn Co Owner - <AUTHOR> http://www.techcrunch.com/2007/07/11/stickam-would-you-let-you-children-use-a-service-owned-by-pornographers/ <comment><USER2> I guess most people would be quick to say, "That's no problem at all", and maybe even add an "of course" statement like _Of course, there is nothing wrong with owning a pornography business_ , even though there are plainly a few things wrong with it.

Funny how the received wisdom of the day changes, and how most morality is so knee-jerk. In the past, any association with pornography would have been deeply shameful. Now, if the MSM published a "story" on how phillip morris owns Nabisco, you can bet there would be a lot of people expressing outrage over that association (cigarettes, unlike porn, being quite evil). Oh well.

<comment><USER3> I just figure that if the people running it weren't sharing an office with a porn service, they'd probably still go home and watch lots of pornography at home. I am almost inclined to have more trust in somebody running a porn business than someone who is not, with respect to child molesting - I think the people suppressing their desires might be more dangerous in the end.

</comment></comment><comment><USER4> no it's not. It's owned by a group run by a man who also happens to run porn companies.

</comment><comment><USER3> I fail to see the problem.</comment>


The 75 — 20 — 5 Rule - <AUTHOR> https://medium.com/tech-blogging/43d78a82e103

<comment><USER2> Wonder if this article itself falls into that 75%, 20%, or 5%. As the author says himself: "The likelihood that what you're reading is completely accurate is very, very, very small. There may be some truth there. There may be none. Just know that."</comment>


Daimler Uses Blockchain to Issue Bonds - <AUTHOR> https://blogs.wsj.com/cfo/2017/07/12/daimler-uses-blockchain-to-issue-bonds/ <comment><USER2> I'm not a blockchain "expert", but this seems somewhere between misguided and insane to me. How could this possibly better than a secure web server and http user interface by any metric?

\- security: how could this possibly be better than a system under your own IT's control?

\- security part 2: introduces a whole new set of vulnerabilities and ways for things to go wrong. e.g. a miswritten "smart" contract.

\- speed: how could this be faster than a web interface and a single server?

Blockchain solves one main problem: Decentralization. The reason for decentralization is the lack of a single trusted authority who says e.g. whether a particular transaction has occurred or not. In this setting you still have and need Daimler to be the trusted authority (unless I misunderstand), so the sole raison d'etre for blockchain is gone.

When you add that to all the downsides and security risks ... let me know if there is an easy way to bet against this.

<comment><USER3> The whole point is to cryptographically be able to prove ownership of something to the network. Given that bitcoins, litecoins and ether aren't magically disappearing out of people's wallets I think its pretty safe to say these systems can be designed in ways which are secure (at least secure enough for the marketcaps of each of those cryptocurrencies which is billions).

If I get a piece of paper that says I own some asset there is offices full of people who are dedicated to ensuring that piece of paper properly represents some piece of land, car, security etc. Why would you not want to automate such a system?

Not to mention once you can create such a system the chains of trust can extend beyond just your bond issuance, you can tie actions from other trusted systems into your bond issuing system in a fully automated way.

<comment><USER2> I don't quite understand your last paragraph, but for the rest:

> _The whole point is to cryptographically be able to prove ownership of > something to the network._

I don't think that's the problem that blockchains solve. That problem can be solved without blockchain just by using public/private key cryptography and digital signatures, along with for instance a public ledger. But a public ledger doesn't need to be distributed and subject to consensus protocols, mining dynamics, etc. It can simply be hosted on a website.

<comment><USER4> It is though. You cant ensure ownership if there is no third party the point that of the blockchain is that it solves that issue by turning the entire network into the notarius. Public/private key cryptography does not solve that.

<comment><USER2> You're talking about a different problem - not having a trusted third party or authority. I agree that blockchain solves that problem (well, it tries).

</comment></comment></comment></comment></comment><comment><USER5> This is proof of concept. This changes everything. The article talks about the company not being ready to use Blockchain to issue all it's bonds due to regulatory questions that still need to be answered but , i suspect, it's only going to be years not decades when this will happen. This spells out big problems to the staff employees associated with Finance.

Anyone in the Financial Industry should start getting ready for the big Finance disruption that's coming in the near future.

<comment><USER6> This changes nothing. It was a publicity stunt that solved no actual problems and introduced tons of problems that didn't exist before. Except it didn't even do that because "regulators do not yet allow issuances via blockchain only, so we had to test it in parallel with the conventional issuance process."

It was a no-op.

<comment><USER7> It's a big deal imo, but a major blow for Bitcoin, because it's nowhere to be seen.

Have you ever purchased a bond? Ever wanted to sell one on the secondary market? Ever heard of the Securities Transfer Agents Medallion Program? You will if you try to trade bonds in the conventional way, which is a huge pain in the ass.

There is a lot of room for improvement by implementing the blockchain.

<comment><USER6> What happens when I buy a bond and then I accidentally lose my private key?

<comment><USER7> I don't think JP Morgan is going to give you the private key to your bond. This is a slightly more decentralized version of holding securities in street name. It's less painful than direct registration, it's publicly auditable, and faster to settle.

<comment><USER6> What happens when JP Morgan loses my private key?

I mean, I hear you. I 100% get why people are interested. I just don't see why it has to be a blockchain vs a centralized database that DTCC controls access to.

<comment><USER8> Databases are notoriously insecure.

<comment><USER6> Databases store all the money for basically everyone in the developed world. They seem to be working ok.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER7> This is the main application for Bitcoin IMO: custody and trade settlement in securities. I have wanted to do this exact thing, issue bonds on a blockchain for some industry or government, since I found out about Bitcoin. Unfortunately, I do not have the kinds of connections necessary to be in the same room as major corporate bond sellers.

Between this news and the DTCC using blockchain for CDS it seems to me that Bitcoin is going to get left behind by the old world companies it sought to replace. Blockstream seems too happy to sit on their hands while the speculative value of Bitcoin increases, not realizing that the chance to actually matter in the world of finance is slipping through their fingers.

Bad news for Bitcoin: [http://m.nasdaq.com/article/dtcc-to-launch-blockchain- credit...](http://m.nasdaq.com/article/dtcc-to-launch-blockchain-credit- default-swaps-reporting-in-early-2018-cm794771)

<comment><USER9> Why wouldn't they use Ethereum?

<comment><USER7> Ethereum's main selling point is it lets you issue illegal unregistered securities. Why would a real company want to associate with that?

Also the lead developer is some kid who believes very much in moving fast and breaking things. This philosophy may work for a social network site but not for other people's money.

How many terrible bugs have been discovered in Ethereums short history? Too many. Additionally the size of its blockchain has already passed Bitcoin. It's file size is growing so fast and will pose a serious technical problem.

<comment><USER9> Bitcoin is used for drugs, prostitution, and gambling.

That terrible bug was the DAO, but that's the nature of the blockchain and applies to Bitcoin as well. If you want rollbacks you use a centralized server.

<comment><USER10> Where can you pay for prostitutes with bitcoin? I've only ever seen cash and credit cards accepted.

<comment><USER9> I'm not familiar, but I know that 99% of the current startups that are using the ICO model are not targeting what made Bitcoin popular.

</comment></comment></comment></comment></comment></comment><comment><USER11> Twitter link to article to bypass paywall: [https://twitter.com/infosblockchain/status/88594050066600345...](https://twitter.com/infosblockchain/status/885940500666003456)

<comment><USER12> I didn't run into a paywall, perhaps because it's on the blogs subdomain. But if anyone needs it, here is the paywall bypass code for all WSJ articles:

[http://salzeko.com/wsj](http://salzeko.com/wsj)

</comment></comment><comment><USER13> > Regulators do not yet allow issuances via blockchain only, so we had to test > it in parallel with the conventional issuance process.

</comment><comment><USER14> Is this what they are going to use?

[https://www.hyperledger.org/projects/sawtooth/bond-case- stud...](https://www.hyperledger.org/projects/sawtooth/bond-case-study)

<comment><USER3> It's hard to say which implementation will be used but the fabric project from hyperledger seems to have the most momentum.

</comment></comment><comment><USER15> How is something like this funded? Charity organizations? Is Google just paying for it?

<comment><USER6> It's a joint project by a bunch of major financial firms.

</comment></comment><comment><USER16> Is this on ethereum?

<comment><USER17> > _Is this on ethereum?_

No. "In February, we joined the Hyperledger Project — a cross-industry initiative — to drive blockchain technology and open standards in collaboration with other firms" [1].

[1] [https://blogs.wsj.com/cfo/2017/07/12/daimler-uses- blockchain...](https://blogs.wsj.com/cfo/2017/07/12/daimler-uses-blockchain- to-issue-bonds/)</comment></comment>


Does an NDA make sense for outsourced developers during startup? - <AUTHOR>

I'm starting a startup, and I'm considering the option of outsourcing parts of the prototype development. I'd be interested in the opinion of everyone here on the following:
1. What is your opinion about outsourcing initial prototype work in the first place? 2. To what extent do you think an NDA for outsourced developers is effective in protecting the 'idea'? 3. If this happens to be a not-so uncommon occurrence, I'd appreciate pointers in the direction of a generic NDA pertaining to this particular circumstance.
Thanks. <comment><USER2> Have them sign an NDA, and only disclose on a need-to-know basis. For example don't disclose information about unrelated business processes or complex modules. If you are new to outsourcing or you haven't worked with the outsourcing team before, it's always better to outsource only the less complicated and low risk functionality to start with.

I'd rather hire a reputed techie or small team at RentACoder.com Or oDesk.com. They take care of payment escrow and NDA's etc.</comment>


Show HN: Coding Interview Practice - <AUTHOR> https://www.interviewcake.com <comment><USER2> I have zero desire to play these silly games. Sorry, I'm much more than a 40 minute probability puzzle! The only way to win is stop playing. Give me a problem to take home, and think about. Or, how about asking me about my skills (and having a conversation about a piece of code). How about pair-programming? TDD abilities count for nothing, whaaaa?

These types of tests do little more than reinforce stale ideas and turn away unconventional well-rounded candidates. Used to play the game, now I win because I don't play.

<comment><USER3> Absolutely,

Interview questions should hinge on, like, the experience and competence that I already have from having worked a substantial period of time as a professional computer programmer. Not on how cleverly I do on BS.

And I actually generally do very well on this crap but I still hate being impelled to take part in this kind of circus. In fact, it's annoying that I jump to being a top candidate based on this stuff and only then does an employer come up with some mundane requirement that should have been the initial qualifier/disqualifier.

<comment><USER4> It is amazing to me to see computer science fundamentals hand-waved away as 'crap' and 'BS'.

<comment><USER5> I don't think anyone would claim these things are crap or BS, I think it's that these silly problem are irrelevant. These questions are like high school or college coursework, artificial questions designed to reinforce the instruction, but not something that would be encountered in a business setting. Additionally, they tend to gloss over a person's experience. I may not be able to solve your silly little stock trading problem by myself in a short amount of time, but I am sure that within the normal development environment, I could, especially since I would be working with a team. Or could I? Since this question doesn't look into my ability to communicate or work within a team, you don't know. Also, while I may not be able to solve the problem in 45 minutes, maybe I should talk about the time I dove into an application written in a foreign technology and managed to solve a critical production bug before it could cost the company millions of dollar. But again, you don't know that because you're obsessed with my ability to solve a high school computer science problem. Different jobs require different skills. Having the ability to code is important, but not nearly as important as teamwork, communication, and the willingness to learn something new. That's the problem with these questions, they are nothing more than smoke screen.

</comment></comment></comment></comment><comment><USER6> It's getting a bit ridiculous how much effort and talent is now dedicated to preparing candidates for interviews.

<comment><USER7> I'm from Central America. I went to SF and had a few interviews over a month. I failed in all those 40-minutes-solve-as-many-as-possible-fizzbuzz-problems because I wasn't fast enough.

That said, I've been working as a web developer for 11 years now, bulding CRM's, CMS', Crawlers, automation tools, and all kind of web based stuff companies needed.

Also, I never went to college, and have been working before finishing high school (15 years old).

So, while I lack a lot of computer science education, I consider myself competent at developing solutions, and have progressed with coding practices.

But because of the US interviewing style, which I had never gone throug before, I am not employable there. Interview Cake may be just what I need : )

<comment><USER8> Look beyond SF.

<comment><USER7> That is the plan :)

Im in LA right now and will check other places.

</comment></comment></comment></comment><comment><USER9> This is such a huge indication of the horribly sad state of interviewing and hiring programmers.

The current process results in hiring people that are awesome at interview quiz questions, but can't sit down and do the actual day-to-day work.

<comment><USER10> It goes without saying that solving algorithm questions are only a part of the interview process. Candidates are also judged on culture fit and design skills.

<comment><USER11> 'Culture fit' \-- the wild card that lets you reject any candidate.

<comment><USER12> A nebulous description of a vitally important quality - someone who your existing team won't hate. It's one-sided to claim that people only use it to unfairly reject candidates. Being an a __hole is something I 'd like to see candidates rejected for, but it won't show up in a technical assessment.

<comment><USER13> > Being an ahole is something I'd like to see candidates rejected for, but it > won't show up in a technical assessment.

I'm not sure that shows up in hours of interviews either...especially when most (all?) of that time is spent on "technical assessment"

<comment><USER4> It filters out the people whose ego won't let them take the test.

<comment><USER14> And people who don't think tests are a good start to a relationship between an employee and a company.

And people who are getting better offers at better companies.

You'll never know.

</comment></comment></comment></comment></comment></comment></comment><comment><USER15> A bit of a nitpick, but the stock trading question should have stated up front that short-selling was not allowed or that the purchase order must precede the sell order. (I suspect someone with some familiarity with trading would have asked these questions in an actual interview for clarification)

Relying on a "hint" to figure out that you can only sell after you buy seems more like an additional constraint rather than a true hint.

<comment><USER16> I feel like completely specifying the problem does everyone in an actual engineering interview a disservice and isn't a good analogue to actual engineering problem-solving. That said, it might be acceptable or even encouraged for the purposes of this site.

In the case that you mention, if someone asked me "Can I short sell?" I'd be happy that they considered the order of events there and were trying to explore the problem. I'd certainly remember it in my interview feedback. My response as an interviewer would be more or less "That's an interesting thought. To simplify the problem, let's say we're risk averse and prefer a finite loss potential. Go ahead and just consider purchase before sale."

One of the biggest criteria I looked for from junior engineering candidates was that they didn't just jump into implementation and asked clarifying questions. That's hard to do with the sort of site this is so maybe in this case more complete specification is useful, but any way that a bit of ambiguity can be introduced means that you can have a meaningful conversation with an engineer about representation, the shape of the problem, the inputs, what the criteria for success are, what is truly necessary to solve a problem. I want working code in the end, but hearing the things a person does or does not consider about a problem is interesting and valuable to understand a potential teammate and how they think.

<comment><USER15> I don't have a problem with a vague question and in fact a candidate asking clarifying questions is indeed a Good Thing.

However the way the question was phrased just makes it seem like the person who phrased it doesn't understand how trading works in real markets.

</comment></comment></comment><comment><USER17> Alice got in facebook just attended coding boot camp and did some algorithm practices. Why does facebook recruit a non experienced like Alice but turns off lots of talented (with a top school cs degree)/with decent working experiences? I am curious.

<comment><USER18> _> >Why does facebook recruit a non experienced like Alice but turns off lots of talented (with a top school cs degree)/with decent working experiences?_

I don't know what you're considering "talented", but Google seems to believe that your school/GPA has almost nothing to do with how well you'll perform on the job.

NOTE: Let's not confuse this with how likely you are to become another Zuckerberg. Starting a company is completely different from working at one. I don't think Zuckerberg could work at Google. He'd be bored out of his mind and/or argue with everyone, then quit in less than a year.

[https://www.linkedin.com/today/post/article/20130620142512-3...](https://www.linkedin.com/today/post/article/20130620142512-35894743-on- gpas-and-brain-teasers-new-insights-from-google-on-recruiting-and-hiring)

 _" GPAs don't predict anything about who is going to be a successful employee. "One of the things we've seen from all our data crunching is that G.P.A.'s are worthless as a criteria for hiring, and test scores are worthless — no correlation at all except for brand-new college grads, where there's a slight correlation," Bock said. "Google famously used to ask everyone for a transcript and G.P.A.'s and test scores, but we don't anymore, unless you're just a few years out of school. We found that they don't predict anything. What's interesting is the proportion of people without any college education at Google has increased over time as well. So we have teams where you have 14 percent of the team made up of people who've never gone to college."_

</comment></comment><comment><USER19> The line, "this is not just another technical question database" is really effective. You anticipate the first possible criticism someone might have and dispel it. I'll definitely give this a whirl soon, great work.

<comment><USER20> But it kind of IS and the fact that the quality and quantity of questions is far inferior to some of the other books on interview prep I've looked at in the past.

<comment><USER21> I'd say the step-by-step hint process is the secret sauce. It mimics an actual interview scenario (where a generous interviewer might be willing to help you along) while teaching by example some structured ways to break down the problem by walking through it step by step. Notably, most of the answers start with a brute-force solution and optimize from there, which (IMO) is an excellent way to approach these sorts of problems, especially in a stressful situation such as a real job interview.

<comment><AUTHOR> Man, can I get your help writing sales copy? :P

</comment></comment></comment></comment><comment><USER22> [https://www.interviewcake.com/all- questions](https://www.interviewcake.com/all-questions) (link is commented out in the page source)

<comment><AUTHOR> Yeah, that page is there so people who have finished all questions can go back and review. You can basically get around the paywall using this link. I figure people who dig around to find a way around the paywall probably wouldn't have paid anyway :P

<comment><USER23> If I pay to get all the questions only to learn later that I could have accessed them all easily for free, I'm going to feel ripped off, even if it was only $5. Either make sure the questions are blocked off properly or let everyone have access to all of the questions. You can't have it both ways here.

<comment><USER24> If I pay for this Pepsi only to learn later that I could have easily stuck it in my coat for free, I'm going to feel ripped off, even if it was only $1.25. Either make sure someone's watching me at all times and patting down my coat at the door properly, or let everyone have Pepsis for free.

Doesn't seem quite as appropriate when the context is changed, does it?

<comment><USER23> Reading through this I see I was wrong. Thank you.

My reaction was provoked when I was considering paying for the rest of the questions, saw the comments and saw the link to all of them. I was too hasty in my response.

</comment></comment></comment></comment></comment><comment><USER25> Interviewcake.com is awesome. At TechCareerHQ, we buy all our student memberships because of the quality of the questions and ability of students to focus on one question at a time. After using Interviewcake, our students are much more prepared for interviews.

</comment><comment><USER26> I wonder if they'll eventually allow anyone to go to this site too be interviewed, live, by an actual engineer. For example, a prospect just shows up and jumps right into a technical interview with an interviewer from an interested company. It'd be good practice from the perspective of the engineer and act as potential job applicant from the perspective of the interviewer. Totally non-committal. I would imagine multiple prospects doing the interviews at the same time with the same interviewer.

Instead of scheduling an interview, you have prospective companies posting their interview schedules. For instance, "Hi, I'm from Google. I'll be hosting a technical interview at 330 PST. If you'd like to potentially work for Google, go to this link and answer my question in the time allotted. I'll be in the room to answer any questions." Of course, there's no whiteboarding involved but it might act as a pretty decent vetting process.

</comment><comment><USER27> I like this a lot.

Went ahead and signed up as some of what's there is probably bit over my head. Looking forward to seeing it grow.

I'd love to see even more discussion on each solution. Ideally something like an interactive "The Practice of Programming" [0].

0: [http://www.amazon.com/dp/020161586X/](http://www.amazon.com/dp/020161586X/)

</comment><comment><USER28> Spoilers in its URLs? I'm on the search engine one and the URL says "compress- url-list"

I guess I was a bit off-base, I was thinking about using a database.

Well cool, this trie thing it suggests is pretty much what I was thinking, and something I'd thought about before without knowing what it was called.

</comment><comment><USER29> I love this idea and the way the problems are presented.

One suggestion (based on the one question I saw) is to also mention at least in passing, concerns with edge cases in the inputs. Python often lets you ignore these things but interviewers tend to be charmed by at least an attention to the possibility that your input is empty.

Also, it might be worthwhile to have some "homework" problems that don't have solutions that are variations of the main problem.

For example, the stock price problem is sometimes presented as changes in price rather than absolute price. This adds some subtle differences that might throw people off unless they've tried it.

I imagine similar variations exist for all the problems available.

<comment><USER30> Say at Microsoft interviewers will drill you on edge cases (but it really is common in most shops). That means all empty / invalid input as well as overflow, floating point errors etc. Some places care about reliability vs speed or elegance more than others.

</comment></comment><comment><USER31> Looks like the site has been improved considerably since I last checked it out, love the new content and context (especially the story about Alice in the about page).

</comment><comment><USER32> This is a very good list - I was asked a bunch of these & thankfully I was able to solve them & land the job. It's _significantly_ harder to solve these if you require immutability (which they did in my case, since we work with Scala)

For example, the stock price problem ([https://www.interviewcake.com/question/stock- price](https://www.interviewcake.com/question/stock-price) ), if you insist the solution has no mutables, I really don't know how a Java/Python/C guy would approach it. In Scala, you'd do

           import math._
           val s = List.fill[Int](100)((random*1000).toInt)
           s./:((s.head,0)){(a,b)=>(min(b,a._1),max(a._2,b-min(b,a._1)))}._2

<comment><USER33> I can't really understand your version, I'm not familiar with scala. Is this somewhat equivalent? I tried to use Clojure's loop/recur but I'm too much of a noob. :(

        def max_profit(stocks):
            def r(stocks, profit, lowest):
                return r(stocks[1:],
                         max([profit, stocks[0] - lowest]),
                         min([lowest, stocks[0]]))
            return r(stocks[1:], 0, stocks[0])

<comment><USER32> I think so. You've basically reimplemented a fold, but clojure stdlib has a built-in left fold. See line 84 [https://github.com/clojure/clojure/blob/master/src/clj/cloju...](https://github.com/clojure/clojure/blob/master/src/clj/clojure/core/reducers.clj)

</comment></comment></comment><comment><AUTHOR> Love to get some thoughts from people on the pricing. Today the first 3 questions are free, and it's $5 for access to the other 11. How would people feel about $10? $20? What if there were 30 questions, sorted into different topics?

<comment><USER34> I'd expect it to provide about the same value as a book, and be browseable; not something that is purely linear one after the other (e.g., I could skip to dynamic programming, graph algorithms, or whatever topics there happen to be). I think that a basic interview puzzle book should be in the range of $25-$40, and depending on that price point be from 150 to 300 pages, with roughly 50-100 problems.

Though, admittedly, I wouldn't pay for this at the moment because I'm happily employed. I did spend about $100 on books to brush up when I was interviewing in late 2011. I found actually the best practice for interviewing was going on interviews (I ended up interviewing at around dozen companies over the span of a month after I was laid off).

</comment></comment><comment><USER35> Parker (creator) does a wonderful job of laying out the different techniques to preform well on technical interviews. The format is easily understood and flow of questions is gradual enough to traverse.

</comment><comment><USER36> Hey gameguy43, Great site! Can you tell us about the tech you used to build it? I see Heroku... Is that Bootstrap too? What language/framework/database are you using? Thanks!

<comment><AUTHOR> Hey there! Yep, bootstrap and angularjs in the front, Django in the back. Cloudfront CDN to handle the static assets (I've /really/ fallen in love with their product--so easy to set up). And of course, Stripe for payments.

</comment></comment><comment><USER37> The problem involving a duplicate number from 1..n... The sum 1+2+...+n is just n(n+1)/2\. Something worth knowing for this sort of "trick" problem.

<comment><USER38> What if the summing overflow? Why not just XOR all the numbers in the set with 1...n (assuming the question is there is only one duplicate in integers in range [1,n]).

<comment><USER39> I feel what you asked is a really nice follow up question, as tricks to not get a overflow could be highly non-trivial.

One can do addition mod n. As long as 2n doesn't overflow, you are good.

You can further improve it by not using any number larger than n. Say we want to sum a+b mod n, wlog assume a<b. If a+b<=n, we are good. If not, then b>n-a. Note a+b mod n = a+(n-a)+(b-(n-a)) mod n = (b-(n-a)) mod n. Now the calculation doesn't overflow.

Here is something to show avoid overflow can be quite difficult... [http://cstheory.stackexchange.com/questions/19591/avoiding-o...](http://cstheory.stackexchange.com/questions/19591/avoiding- overflow-in-finding-a-solution-toax-by-c)

<comment><USER38> > One can do addition mod n. As long as 2n doesn't overflow, you are good.

I wonder if the result will still be correct. It's possible to have multiple answers. e.g. (7 + 10) % 6 = 5. But both 5, 11, 17 % 5 == 5. Can you find which one is the actual sum though?

\---btw, the xor solution--- (defn find-dup [dup_set test_set] (reduce #(. clojure.lang.Numbers xor %1 %2) (into dup_set test_set)))

<comment><USER39> If we sum all the numbers we get n(n+1)/2 + x, where x is the duplicate number. Assume n(n+1)/2 = a mod n.

If we did mod n addition the whole way, we have the result a+x mod n, and let that number be b.

Claim: if a + x = b mod n, then there is a unique solution x in between 0 and n-1. In fact x = (b - a) % n.

Now, if x = 0 from the above computation, you would know it is n instead of 0.

<comment><USER38> But x is not necessarily smaller than n though. For example:

Duplicate array: [1,2,2,3,4]. If you do mod 2 sum, then you have 1+0+0+1+0 = 2 mod 0 = 0. But another possible duplicate set can be: [1,2,3,4,4].

10 + x = 0 mod 2 (see 4%2 = 0 and 2%2 = 0? So x can be either 2 or 4.) If you let modulus number N be larger than n (e.g. n = 5 in my example, just let N = 6. Then 10 + x = 0 mod 6 will yield only one possible solution that is 2) then I think your solution will definitely work.

But I think the big problem is: you said x = (b - a) % n. That is true, but how do we get "a" (the sum of all unique numbers from 1 to n) without overflowing? The reason we do modulus summation is for avoiding overflow, granted that can get "b" easily, yet now we have to find "a" still, I find we are still stuck. Any suggestion?

Even if assuming everything will work out and my previous question can be responded, still the modulus function is WAY MORE expensive to compute than xor operation.

<comment><USER39> > If you let modulus number N be larger than n (e.g. n = 5 in my example, just > let N = 6. Then 10 + x = 0 mod 6 will yield only one possible solution that > is 2) then I think your solution will definitely work.

That was entirely what I was suggesting, but we don't need N>n. N=n would work. (btw, I defined n to be the size of the list -1, therefore in your example, the number is 4)

> But I think the big problem is: you said x = (b - a) % n. That is true, but > how do we get "a" (the sum of all unique numbers from 1 to n) without > overflowing? The reason we do modulus summation is for avoiding overflow, > granted that can get "b" easily, yet now we have to find "a" still, I find > we are still stuck. Any suggestion?

We can compute a using the same function that computes b. just sum all numbers from 1 to n mod n. Here is a quick demonstration in Haskell.

[http://lpaste.net/101868](http://lpaste.net/101868)

> Even if assuming everything will work out and my previous question can be > responded, still the modulus function is WAY MORE expensive to compute than > xor operation.

True. I just want to show how to modify another solution so there is no overflow.

</comment></comment></comment></comment></comment></comment></comment><comment><USER40> I used to have a site like this but only show one hint. Love the concept of having multiple levels of hints though!

www.InterTechTion.com

Edit: Link to archive of all questions I sent out: [http://www.intertechtion.com/answers/](http://www.intertechtion.com/answers/)

</comment><comment><USER41> Subscriber here, I felt like I needed interview preparation to be able to go through this interview preparation. I think it would be helpful to list some resources for those less well-versed with these types of problems.

Will you be adding more questions in the future?

I do like the concept of the site!

<comment><AUTHOR> Hey there,

The problems are definitely a bit more advanced. I do try to make sure that any "vocab words" (data structures, algorithm types) can be clicked on for a deeper explanation. But if you haven't seen big-o before, for example, you'll be in the dark on a few things right now. I have some more "bottom-up" curriculum that I've developed from teaching at boot camps around San Francisco, and I'm still working on figuring out the best way to present it on the site.

For Big-o specifically (the thing that looks like "O(n)"), I really like these resources: [http://stackoverflow.com/questions/487258/plain-english- expl...](http://stackoverflow.com/questions/487258/plain-english-explanation- of-big-o/487278#487278) [http://www.perlmonks.org/?node_id=227909](http://www.perlmonks.org/?node_id=227909) [http://www.daveperrett.com/articles/2010/12/07/comp- sci-101-...](http://www.daveperrett.com/articles/2010/12/07/comp-sci-101-big- o-notation/)

Best of luck!

</comment></comment><comment><USER42> Good execution on a simple premise. Another terrific resource that I've pointed a lot of friends to is Project Euler -- a little heavy on the math but a lot of interesting questions that are great prep for the Google (or Facebook, or Twitter, etc.) gauntlet.

</comment><comment><USER43> The step by step expansion are really great, and I'm sure this will help many.

I think I prefer the learning by doing approach like talentbuddy[1] personally.

[1] [http://www.talentbuddy.co/](http://www.talentbuddy.co/)

</comment><comment><USER44> Yes! I got the first question right. Somebody should hire me as a programmer. :D

</comment><comment><AUTHOR> Sorry the site's a little slow guys. I'm up to 100 dynos on Heroku but things are still a bit sluggish at times. Looks like I need to move more stuff over to the CDN? Thanks for the load testing!

</comment><comment><USER45> For the indexing the web question (what data structure should an under- resourced web-crawler use to keep track of visited links?) wouldn't a Bloom filter work better than a trie?

<comment><USER46> They mention it, actually.

</comment></comment><comment><USER47> Holy cat snacks, this page uses a lot of third-party JavaScript.

<comment><USER10> I'm up-voting this just for your use of "Holy cat snacks," BWAHAHA.

</comment></comment><comment><USER48> First question is wrong, I could have just sold short. ;)

</comment><comment><USER49> I haven't tried it yet, but will later tonight. I just dropped by to say that this is a great problem to solve. It addresses an emerging market.

</comment><comment><USER50> I noticed on the 'Validate string with open/close is well formed' question an edge case that's not handled. If the input has a trailing closer char with an unmatched opener, an IndexError will be raised because the stack will be empty when you try to pop from it. (Unless your particular Stack class just returns None or something? But then you'll get a KeyError when trying to access that key in the dict.)

</comment><comment><USER20> Any one has a link to all the solutions? It's annoying to get to those via hints all the time.

</comment><comment><USER51> Could use some syntax highlighting to make the code examples more easily read.

</comment><comment><USER52> Wait, so just to clarify - there are only 14 questions?

</comment><comment><USER53> you know what would be great? having the answer in multiple languages :) just an idea. good luck, nice site, I like it.</comment>


Elon Musk To Traverse The U.S. Using A Model S In 6 Day Trip - <AUTHOR> http://techcrunch.com/2013/09/05/elon-musk-cross-country-tesla-trip/ <comment><USER2>
        > At 1.5 hrs/day, we will only ever need to
        > charge when stopping anyway to eat or sightsee,
        > never just for charging itself.

I'm all for the development of electric cars but downplaying having to stop at what's effectively a gas station in the middle of nowhere for 1.5 hours per day is pretty disingenuous.

You wouldn't get a lot of people buying a normal gasoline powered car if it took 1.5 hrs to fill it up each time, so electric cars have a _lot_ to make up for in other features if you're using them for road trips like this, rather than just commuting where you're charging overnight.

<comment><USER3> It's free. If you could get gasoline for 200 miles for free, would you mind waiting for 30 minutes? I guess it's $25-30 worth of gasoline, corresponding to $50-60 per hour of waiting. I could wait.

With the battery swap that Tesla is now introducing, you could also chose to swap the battery in a couple of minutes.

<comment><USER4> charging electric cars ain't free.

<comment><USER5> No, but using the Tesla Supercharger stations is free for Model S owners.

<comment><USER6> It costs $80,000 but it comes with a free car.

</comment></comment></comment></comment></comment><comment><USER7> Wonder if he uses the air conditioning? Wonder how many people are in the car? Are there places he can't visit specifically because there aren't charging stations - sorry I don't know his route. I wish him success, but he seems to gloss over a lot of details ...

</comment><comment><USER8> He should do it in 7 and take some breaks to see some stuff.

Source: I've done it in 6 and 7 days, 7 was way more fun, way more relaxing and I learned more.

<comment><USER9> That's more than 700km per day. So given the speed limit it means you are spending most of the week in the car. How is this fun?

<comment><USER10> At interstate speeds (~75mph/120kmph) that's just under 6 hours a day in the car. That leaves a short but reasonably good amount of time to sight see at either end or in the middle of each day.

</comment></comment></comment><comment><USER11> I was wondering why someone hadn't done this. It's a bit of dangerous press. If the car breaks down, or runs out of battery for some reason, that's not going to look good. Bit of a gamble.

<comment><USER12> Most 'normal' people already give electric vehicles a cynical eye. The people who already believe in them don't need more convincing. The cynics need convincing. A breakdown will only make them think "I knew it" while a successful trip will at least add one more argument against their cynicism. Not much of a gamble in my opinion.

</comment></comment><comment><USER13> Remember that this answers the question "Can you get an electric car from coast-to-coast?" and not "Can you use an electric car for your coast-to-coast vacation?" And that Tesla wants you to think it's the latter.

Clever marketers.

<comment><USER14> It echoes the first coast-to-coast trip by H. Jackson and S Crocker[1] in 1903, except Musk is starting from LA instead of San Francisco.

[1] [http://amhistory.si.edu/onthemove/exhibition/exhibition_7_2....](http://amhistory.si.edu/onthemove/exhibition/exhibition_7_2.html)

</comment></comment><comment><USER15> Is there plans on making the supercharge stations available for other manufacturer's electric cars (although not for free)? The thing that could really make this take off is if they can standardize this technology. After all, I don't think gas cars would be as convenient if you had to fill up only at a Ford gas station, or a Honda station, etc.

Even if there are multiple charging standards, just have several charging cables at each "pump".

<comment><USER16> Most cars come with adapters for the various kinds of station.

</comment></comment><comment><USER17> Anyone know if he is only charging at tesla stations? What's the route he is planning on taking? Is the idea to get food at each stop? Lastly, doesn't he have like 5 kids, how will they all fit in the tesla???

Edit: He does have 5 kids. [http://en.wikipedia.org/wiki/Elon_Musk#Family](http://en.wikipedia.org/wiki/Elon_Musk#Family)

<comment><USER18> One of the design goals with the Model S was to fit Elon's whole family: there are rear-facing seats in the back that fit an extra two people.

<comment><USER17> ah you are correct, hadn't seen that. no room for luggage then. [http://www.teslamotors.com/models/features#/interior](http://www.teslamotors.com/models/features#/interior) guess you can have your luggage for each day fedexed in advance if you're elon.

</comment></comment></comment><comment><USER19> I'm surprised they don't develop a really cool looking mini trailer battery pack to double (or more) your range. It could have some extra room for storage. It'd be great for longer distance camping trips and such outings. The other option would be a clean fuel cell technology (hydrogen?).

<comment><USER16> How about a pack that fits into the "frunk?"

</comment></comment><comment><USER20> It would have been much more impressive if he were to execute a non-stop trip making use of the recently revealed battery swapping technology. Is there some reason why they can't yet install them alongside all interstate Tesla superchargers?

</comment><comment><USER21> The big question is when he's going to take that trip. They're supposed to have the cross country capacity only at the end of the year. Why announce it now and wait 4 months to actually do it?

<comment><USER22> I'd love for him to do it during the coldest months of the year in the Northeast, like February. That will either shut up all the naysayers about cold weather distance driving, or it will shut him up (unlikely) about how good the battery is when it's really, really cold.

</comment></comment><comment><USER12> Have the trip details (like route) been released yet? Is he only stopping at Supercharger location? I'd like to meet him and follow along a while. I'm not a stalker. Really. :)

</comment><comment><USER23> It's great that he has that kind of free time with as much going on as he has.</comment>


Difference in judgements passed by courts in Europe v USA - <AUTHOR> http://arstechnica.com/tech-policy/news/2010/11/42-german-p2p-fine-stark-contrast-to-seven-figure-us-judgments.ars Really interesting that the judge in Europe is allowed to throw out any of the "what if" conjecture about the possible loss in revenue, but the one in the USA doesn't or can't. IANAL. I just find the punishment to not fit the crime at all. <comment><USER2> One difference is that Jammie Thomas-Rasset lied under oath, tried to destroy evidence, tried to blame her kids and others, and has refused quite reasonable settlement offers.

<comment><USER3> That surely sounds serious enough to make him pay probably his whole life. I mean, what a villain!

<comment><USER2> She could have avoided all of this by simply accepting their initial settlement offer. I don't know if the exact amount has been published, but based on the offers that other people got, it would have been in the ballpark of maybe 2-5 thousand dollars, which is not much more than it would cost to legally obtain the couple thousand songs she had downloaded.

It was her choice to go to court rather than settle, even though she had pretty much no case. The actual lawsuit was for only 24 songs. If, for some reason, the court had found that she was an innocent infringer, and awarded the minimum possible statutory damages of $200/song, that would still have been $4800. Since there is pretty much no chance of them finding her to be an innocent infringer, the minimum is $750/song, or $18000.

So, when she turned down their initial, quite reasonable, settlement offer, she was looking at an almost certain loss in court for a _minimum_ of $18000. The jury gets to decide the actual amount, and they can go way higher than $750/song. When the defendant lies, tampers with evidence, and tries to blame their kids and others, you think a jury is going to go for the minimum? No way.

This is now the third time it has been to court. After each victory in court (each of which resulted in a larger damages award than the previous one), the RIAA has offered to settle for much much less than the court awarded. And yet she still turns them down.

I have no sympathy whatsoever for a defendant who exhibits such monumental stupidity.</comment></comment></comment>