This is the design I usually use for intro games at conventions:
Compact, Heavy chassis, Heavy suspension, Large power plant, 4
Steelbelted Puncture-Resistant Radial tires, Driver w/TC and BA and
PFE, Light Laser in Turret, Recoilless Rifle Front w/10 shots HEAT,
Plastic Armor: F22, L17, R17, B17, T16, U4, Gear Allocation: [72 lbs.
@ Accel 5/Top Speed 117.5], Acceleration 10, Top Speed 120, HC 4,
3998 lbs., $14834
Everyone gets the same car.
Acceleration 10 cuts down on needing to explain half moves early. TC and compact cancel each other out... one less modifier to worry about. No dropped weapons to reduce clutter and rules explanations. The turreted laser ensures that they can always shoot at something. The RR front gives them some tactical choices and teaches about lining up cars for shot. The armor is about enough to sustain two shots from the main gun (with the front being a bit heavier). Tires are tough enough to make side shots generally a better option. PFE in case of fires - another choice... to fire or get rid of the fire.
Minimal extra gear to need to know rules for (nothing really - most are static). A heavier car would simplify collisions, BUT I found that it made collisions way too effective the time I tried it.
Get or make some tokens for players to track firing actions and speed changes (this helps a LOT at conventions). Business card size or even notecards work pretty well.
Start with a really short background to the game: I usually start with something like: "Car Wars is a game of the roads of the future, where the right of way goes to the biggest guns." One of the most popular forms of entertainment is drivers matching their skills in arena combat. You are those drivers. Your objective: Eliminate the other players before they eliminate you."
In the convention games I run (which are timeboxed to about 2 hours), I set the victory condition as the survivor with the most kills, and a tiebreaker being the player with the earliest kill.
Next I talk turn structure: turns and phases. Then explain the phase structure in order and how to perform them.
First is speed changes (optional, once per TURN). Use those markers/tokens I mentioned to track this - have them discard it to the table so you know who has and hasn't changed speed.
Second I do movement (mandatory) and introduce the movement chart. Introduce the turn key. Show how to move a car, adjust handling, determine if they're in control (skip the crash tables until someone loses control). Bends and drifts is usually adequate (skip the others for an intro game). Explain that D is difficulty and anytime you say D something, reduce their handling by that much.
I usually have people move simultaneously unless they are close enough to each other that order is important. Order then by highest speed.
Third is firing (optional once per TURN). Explain the car diagram. How to apply damage. How to fire weapons. Again... those tokens. Have them discard them when they fire. Be prepared with targeting modifiers. Know them. As a referee this is a big time savers. Explain hazards with weapons fire.
Use the unwound speed modifiers so people can understand them (this gets the same result as the normal table, but is generally easier to grasp):
Code:
SPEED MODIFIERS
"Target's
Speed* "Firer is in Target's*
"Left/Right Firing Arc" "Front/Back Firing Arc"
0-27.5 0 0
30 - 37.5 -1 0
40 - 47.5 -2 0
50 - 57.5 -3 0
60 - 67.5 -4 -1
70 - 77.5 -5 -1
80 - 97.5 -6 -2
100 - 117.5 -6 -3
120 - 137.5 -6 -4
140 - 157.5 -6 -5
160+ -6 -6
* If moving the same direction (Firer and Target are completely in each other's opposite firing arcs, i.e. Left and Right or Front and Back), reduce the Target's Speed by the Firer's Speed.
** If firer is in multiple arcs, use the penalty for Left/Right
Explain end-of-turn cleanup steps:
1. Check for fire
2. Fire extinguishers
3. Explosions (doesn't apply to these cars)
4. Recover handling
5. Recover actions (Pick those tokens back up.)
Explain the reflex roll and have people make it, doing roll off tiebreakers as needed. Write this order down. Explain this is the tiebreaker for same speed movement, allowing the person with higher reflex roll to choose who moves first.
Start everyone out at 40 mph. Get rolling.
Explain multiple moves and half moves when someone changes speed to where these apply.
Introduce debris and obstacles when they occur.
Introduce the crash tables when they occur.
Introduce the collision damage on the table when people get close.
The above usually works pretty well.