time when the freeways were built, and is diminishing. Nevertheless, freeways continue to be officially named; for example, State Route 118 was christened the Ronald Reagan Freeway. Rush hour Los Angeles has synchronized its traffic lights. The mean travel time for commuters in Los Angeles is shorter than other major cities, including New York City, Philadelphia and Chicago. Los Angeles' mean travel time for work commutes in 2006 was 29.2 minutes, similar to those of San Francisco and Washington, DC. Rush hour occurs on weekdays between 5 am and 10 am, and in the afternoon between 3 pm and 7 pm (although rush-hour traffic can occasionally spill out to 11 am and start again from 2 pm until as late as 10 pm, especially on Fridays). Traffic can occur at almost any time, particularly before major holidays (including Thanksgiving, Christmas, and three-day weekends) and even on regular weekends when one otherwise would not expect it. Streets, street layout, the boulevards, and street problems The city has an extensive street grid. Arterial streets (referred to as surface streets by locals, in contrast with freeways which are usually grade-separated roadways) connect freeways with smaller neighborhood streets, and are often used to bypass congested freeway routes. Consequently, most of the surface arterial streets in Los Angeles have various forms of congestion control. Some of the more common means of maintaining surface street traffic flow is the use of loop-sensors embedded in the pavement allowing for intersection traffic signal timing adjustments to favor the more heavily delayed roadways; the use of a traffic control system allows for the synchronization of traffic signals to improve traffic flow (as of October 2009 this system is currently installed at 85% of the city's signalized intersections, more than any other US city); restrictions on vehicle turns on roadways without designated turning lanes during rush-hours; and the extensive use of rush-hour parking restrictions, allowing for an extra lane of travel in each direction during peak hours (weekdays excluding holidays generally from 7-9am thru 4-7pm, although hours vary by location) by eliminating on street parking and standing of vehicles, with violators being ticketed, and in the case of priority routes known as "anti-gridlock zones", immediately towed by specialized enforcement teams dubbed "tiger teams" at steep cost to the violator. 1st Street divides the block numbering grid north and south, and southwest of the Los Angeles River, Main Street divides the