TEXT: Running Vehicle Combat
  Notes from the Bunker
  Running Vehicle Combat
  by Rich Redman
  Welcome to your bunker. I'm Rich Redman, one of the designers of the d20 Modern Roleplaying Game. I 
  may not be an expert, but I'm experienced and opinionated. Here in the bunker, I explore some corners of 
  the d20 Modernrules, create rules variants, and offer suggestions based on my experience writing and 
  running games.
  This month's column is the second in a two-part series on vehicles in the d20 Modern game. Last month 
  we talked about creating vehicle statistics from scratch. This installment focuses on vehicle combat. 
  I won't waste your time repeating information that you can find in Chapter Five: Combat in the book. 
  Instead, let's look at an abstract system for vehicle combat.
  Why Abstract?
  One good reason for developing an abstract system is that people have been asking for it for some time 
  now. But the chief advantage of such a system is that you don't need to draw maps. Mapping vehicle 
  combat can be time-consuming both before and during a game. In this system, though, you can use street 
  maps or even go without maps entirely if you want to.
  This system works best when all the characters are in vehicles. If some characters are on foot and some 
  are in vehicles, you're better off using the system presented in Chapter Five: Combat in the d20 Modern 
  Roleplaying Game. Use character scale and let characters outside vehicles have their own initiatives while 
  those inside use the vehicles' initiatives.
  Preparation
  To use this system, you need paper (or several large mats with preprinted grids that work with erasable 
  markers, such as the mats put out by Chessex.). You also need a copy of the d20 Modern rules and your 
  usual supplies for playing the game.
  Optional
  For simulating vehicle combat, I like to use toy vehicles, such as Hot Wheels or Matchbox cars, or other 
  similarly scaled vehicles. (Hot Wheels and Matchbox are both Mattel, Inc. products, but they're also 
  readily available to everyone.) Since this method doesn't rely on squares, it doesn't matter how big the toys 
  or models are in relation to each other. A 1/35th scale plastic model works just as well as a die-cast toy, 
  provided that you make a big enough diagram.
  Alternatively, you could find a copy of Polyhedron magazine #152, which includes vehicle counters that you 
  can photocopy and use in your game. (They're part of a d20 minigame written by yours truly.)
  
  Running Vehicle Combat
  Diagrams
  Draw a large X in the center of your piece of paper or mat. Place or draw the heroes' vehicle in the middle 
  of it, orienting the model so that the X divides the paper into the four firing arcs presented on pages 156 
  and 157 of the d20 Modern Roleplaying Game.
  Burden of Description
  The more abstract a rules system gets, the greater the burden of description it places on you as GM. It's up 
  to you to describe the sounds of roaring engines and squealing tires, the wind on the heroes' faces, the 
  smells of high-octane gasoline and burning rubber, the sensations of the car's movement, and its 
  responses to variations in the road surface. Don't let simple maneuvers and stunts (see below) be reduced 
  to a few die rolls -- really describe them to the players. When you see them leaning forward in their chairs 
  as they imagine the car moving under them, then you're doing it right.
  Feats
  Chapter Three of the d20 Modern Roleplaying Game details three vehicle-related feats. All of these 
  function as written in the abstract system.
  Vehicle Movement and Combat
  Now let's compare this system with the rules presented in Chapter Five: Combat of the d20 Modern 
  Roleplaying Game, looking at the similarities and differences.
  Scale
  Scale matters less in this system than in the regular rules. When we need numbers for vehicle statistics, 
  we'll be using character scale.
  Getting Started
  Place the heroes' vehicle in the center of the diagram. Place the other vehicles in the appropriate firing 
  arcs, and jot down how far away each one is from the one the heroes are in. Also make sure the other 
  vehicles are facing the right way relative to the heroes' vehicle.
  Initiative
  The best way to handle initiative in vehicle combat is to roll for each vehicle rather than for each character. 
  You'll wind up using vehicle initiative anyway, since most characters are likely to hold or ready their actions 
  until the vehicles move into better positions.
  When the heroes' vehicle comes up in the initiative order each round, just start with the driver and go 
  around the table until everyone has acted.
  
  Running Vehicle Combat
  Declaring Speed
  Even though this system doesn't require moving miniatures around a map or redrawing vehicle positions 
  each round, drivers still need to declare speed. You can write the speeds on the diagram beside each 
  vehicle, on a separate sheet of paper, on a 3" x 5" card that the driver's player displays in front of him that 
  round, or in any other convenient manner, just as long as you keep track of it.
  Moving
  Don't move the heroes' vehicle -- ever -- when using this system. Whenever any vehicle moves, simply 
  adjust its position relative to the heroes' vehicle. This concept is the toughest one to grasp when using this 
  system. Once you get it down pat, you're in the homestretch.
  The Effects of Speed
  The effects of speed remain the same under this abstract system.
  Driving a Vehicle
  In this system, a driver can perform the same simple maneuvers that she can using the detailed system in 
  Chapter Five: Combat. The implementation of the maneuvers, however, is somewhat different.
  45-Degree Turn: No change.
  Accelerate: A driver can change his vehicle's speed by one category (faster or slower), just as she can 
  using the detailed system.
  Ram: Because this system is so abstract and there are no squares for vehicles to occupy, ramming 
  requires the same simple maneuver described in the detailed system. If the distance between two vehicles 
  is 1 square or less, a driver may attempt a ram.
  Sideslip: No change.
  Stunts
  This system allows a driver to perform the same stunts as he could using the detailed system in Chapter 
  Five: Combat. The implementation of the stunts, however, is somewhat different.
  Avoid Hazard: As GM, you should warn drivers about hazards as soon as they become visible (or as soon 
  as the driver makes a successful Spot check). Doing so gives drivers the opportunity to use turns and 
  sideslips to avoid the hazards entirely.
  This stunt is designed for avoiding objects in the road that a driver can't simply go around. Normally, such 
  obstacles are no bigger than Large, because a Huge or larger object occupies the entire space that a car 
  does, forcing the car to go around. In this abstract system, however, obstacles can run the full range of 
  sizes, as follows.
  
  Running Vehicle Combat
  Size
  DC
  Large
  15
  Huge
  20
  Gargantuan
  25
  Colossal
  30
  Bootleg Turn: If a vehicle successfully completes a bootleg turn, its facing changes relative to other 
  vehicles. Just turn the model around to establish the new facing. If, for example, a hero's vehicle performed 
  a 180-degree bootleg turn (DC 20 Drive check), the GM would turn the hero's vehicle around (effectively 
  changing which firing arc the other vehicles are in relative to it), and its speed would be zero.
  Dash: No change, as shown in the example below.
  Hard Brake: No change, since this stunt is the reverse of a dash.
  Hard Turn: No change.
  Jump: As with hazards, you should warn drivers about jumps as soon as they become visible.
  Sideswipe: In this system, one vehicle may sideswipe another if both are in one another's side (left or 
  right) firing arcs, moving in the same direction, and no more than 1 square apart.
  Example: Biff Hardslab is in a Corvette. Buck Plankchest (a GM character) pursues Biff in a Lamborghini 
  Diablo. The Diablo faces the Corvette and is in its left firing arc, 10 squares away. The two drivers gun their 
  engines and sneer at each other. Each car has the same -2 modifier to initiative, and Biff wins the check. 
  Biff has no ranks in Drive and no vehicle-related feats, his Dexterity modifier is +1, and the Corvette's 
  maneuver modifier is +0. 
  Biff opts to increase to alley speed and move the full 20 squares. He then decides to attempt a stunt as part 
  of his move action and increase his speed a second category. Doing so requires a DC 15 Drive check, 
  which he fails. The GM describes the smoke from the screeching tires as Biff floors the accelerator but fails 
  to go faster. Biff tries again in lieu of his attack action, and this time he succeeds. The Corvette is now 
  going street speed, and it moves an additional 20 squares, for a total move this round of 40 squares. Biff is 
  nowhere near the Corvette's top speed of 310 squares, but he now has a -1 modifier on his Drive checks 
  (and all other skill checks), as well as his attack rolls. The GM describes the tires suddenly gaining traction, 
  grabbing the road, and hurling the car forward as Biff sinks into the leather-covered bucket seat.
  The GM rules that the change in relative positions shifts the Diablo to the Corvette's rear firing arc. He 
  moves Buck's toy car on the diagram to place it in the Corvette's rear firing arc. It is now 50 squares back 
  and 10 squares over from the Corvette. He tells Biff's player that Biff can see the Diablo in his driver's-side 
  rear-view mirror. Buck increases the Diablo's speed to alley speed, moves 5 squares forward, turns 45 
  degrees toward the Corvette, moves 4 more squares (spending 6 squares of movement because it's a 
  diagonal move), makes another 45-degree turn toward the Corvette, and ends up facing the other vehicle. 
  Both turns are simple maneuvers and therefore free actions, since the Diablo moved farther than its turn 
  number before changing facing either time (at alley speed, the turn number is 1). Each turn costs 1 square 
  
  Running Vehicle Combat
  of movement, but the Diablo still has movement remaining. The GM moves it 6 more squares, ending with 
  a sideslip to put the Diablo directly behind the Corvette. This last stunt costs the final square of movement. 
  The GM draws some arrows on a piece of graph paper to diagram the Diablo's movement, counts squares, 
  and announces that the Diablo is 40 squares behind the Corvette and one square to the left, still in its rear 
  firing arc. He turns the toy car to face the Corvette and tells Biff's player that Biff can see the Diablo 
  accelerate smoothly through the cloud of burnt rubber that the Corvette left and turn effortlessly toward him.
  The GM decides that Buck wants to catch up with Biff, so he attempts a dash stunt. Buck has 9 ranks in 
  Drive and a -1 Dexterity modifier, and the Diablo has a +1 maneuver modifier. He makes a successful DC 
  15 Drive check and easily accelerates to street speed. The Diablo moves forward another 30 squares. The 
  GM notes the new, shorter distance on the diagram. He tells Biff's player that the Diablo zooms forward 
  without so much as squeaking the tires and now looms large in his rear-view mirror. Buck is now 10 
  squares back, easily within the second range increment of his Desert Eagle pistol. He has the same -1 
  modifier on skill checks and attack rolls that Biff does.
  Collisions and Ramming
  Collisions and ramming can result from a simple maneuver (ram), a stunt (sideswipe), or a failed stunt 
  (avoid hazard or jump). The rules do not change.
  Hide and Seek
  These rules are unchanged.
  Fighting from Vehicles
  These rules do not change under this system.
  Maps
  The two best "maps" to use with this system are flowcharts and street maps.
  Flowchart
  On a sheet of paper, draw a space (it doesn't matter what shape) and write the word "Start" in it. From 
  there, draw another space and connect it to the first with a line. That second space is the first point at which 
  an event happens or a decision needs to be made. Note the distance between start and the first event, in 
  squares or in feet, next to the line. This distance gives the crews and passengers opportunities to shoot at 
  each other, ram each other, and so forth. In the second space, jot down notes about the event. 
  Alternaitvely, you could just make a numbered list.
  The huge advantage of this method is that you can create generic flowcharts for any time that vehicle 
  combat occurs. You aren't tied to a map of a place that your heroes may never visit.
  Example: Biff's GM knows that the infamous Strong/Tough hero recently acquired a Chevy Corvette, and 
  despite his utter lack of ranks in Drive, he will want to drive it. To prepare, the GM creates a generic driving 
  
  Running Vehicle Combat
  flowchart.
  1. Start.
  2. Travel: From start, move 150 squares before the first event.
  3. Traffic: This event is optional, depending on time of day. The GM decides that the traffic 
  requires a DC 20 Drive check to avoid, otherwise a collision occurs with a Huge vehicle 
  moving at street speed. Depending on how Biff's player describes his actions, the collision 
  may be head-on or rear impact.
  4. Travel: Move 10 squares to the next event.
  5. Turn: At this point, the vehicles may make a 90-degree turn to the right (see 5a, below), a 
  90-degree turn to the left (see 5b, below), or go straight (see 6, below). Turning requires a 
  DC 10 Drive check for a 90-degree bootleg, but the vehicle's speed drops to zero. 
  Alternatively, the driver can make two 45-degree hard turns. The space required depends 
  on the vehicle's speed.
  5a. If the vehicles turn right, they travel 10 squares and encounter construction. Each driver 
  can make a DC 10 Drive check to avoid Medium-size hazards, or use a conveniently placed 
  steel plate to jump past the construction (DC 35 Drive check, but the GM allows a +10 
  situation bonus on the check for the makeshift ramp).
  5b. If the vehicles turn left, they travel 100 squares before encountering a rising drawbridge. 
  Each vehicle must make a 10-foot jump (DC 25 Drive check, modified by the vehicle's 
  speed category).
  6. Travel: Move 100 squares to the next event.
  7. Accident: A jackknifed tractor-trailer rig blocks the road. Drivers must reverse course or 
  squeeze through a very small space on the right side. A GM using the standard vehicle 
  rules would simply leave a 2-square wide space at one end of the truck, and drivers would 
  have to maneuver their vehicles through it. Instead, the GM refers to the Urban Arcana 
  Campaign Setting, which gives the size of the Peterbilt 379 as Gargantuan (DC 25 to avoid 
  in the abstract system).
  And so on. The neatest aspect of the flowchart method is that you can easily move events where you need 
  them. For example, Biff's GM could easily put the accident 100 squares after either the construction or the 
  drawbridge. He has the notes he needs to adjudicate the situation, and he doesn't have to worry about 
  confusing the players or changing the map.
  Street Map
  Detailed street maps can be found on numerous websites, including Yahoo! and Microsoft Terraserver. If 
  you know where your adventure occurs, you can get a map for that area, print it out, and use it to note 
  vehicle locations. The tough part is estimating travel distances so that you know where on the map the 
  
  Running Vehicle Combat
  vehicles move. Multiply by 5 to change from character-scale squares to feet, then divide that result by 
  5,280 to get miles -- typically a very small number. Alternatively, you can use Rule Zero and make a call as 
  GM.
  Before play, note various hazards on the map, make a ruling about how heavy traffic is likely to be in 
  various places, and generally spice things up. You know the distances involved because they're on the 
  map, and you don't have to place turns for the same reason.
  Parting Words
  Here are a few words of advice on using the abstract system for vehicle combat.
  G     The abstract system is most useful when everyone is in a vehicle.
  G     If you want to make the situation more complex (and use lots of toy cars and trucks), you can make 
  a diagram for each vehicle. Thus, when Biff is in Buck's front firing arc and facing Buck's left, then 
  Buck is in Biff's left firing arc and facing him.
  G     The single most important concept is that a vehicle never moves from the center of its own diagram. 
  Other vehicles move as their relative positions change.
  G     The standard rules work normally with this system, except for those covering collisions.
  G     By working with flowcharts, you can liberate yourself from maps entirely.
  About the Author
  Before Rich Redman came to the RPG R&D department at Wizards of the Coast, Inc., he had been an 
  Army officer, a door-to-door salesman, the manager of a computer store, a fundraiser for a veterans' 
  assistance group, and the manager of Wizards of the Coast, Inc.'s Customer Service department. Rich is a 
  prolific game designer who has worked on the Dungeons & Dragons game, the d20 Modern Roleplaying 
  Game, the Marvel Super Heroes Adventure Game, and Dark*Matter. When he's not working as vice 
  president of The Game Mechanics, a d20 design studio, Rich does freelance game design, cooks, and 
  practices yoga, tai chi, and silat.
  ©1995-2005 Wizards of the Coast, Inc., a subsidiary of Hasbro, Inc. All Rights Reserved. Wizards is 
  headquartered in Renton, Washington, PO Box 707, Renton, WA 98057.
  
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