I did a variant on my style of rules that does use a zone map. Here they are. I'd say they adhere a little more closely to normal conflicts, and I couldn't say which rules I'd use in my own game without running some tests first.
The Map Is Not the Terrain: Zone Maps and ChasesRequires: Chase stress, Zone MapGoalsThe quarry’s objective is to Take Out their pursuers by filling their chase stress tracks. The pursuer’s goal is to fill their quarry’s chase stress track and Take them Out instead.
InitiativeI've decided not to mandate any sort of initiative thing. People will use what they like.
Zone MapWhen you don’t have a specific map in mind, you can use a simple square grid. 5x5 is probably a good mix of plenty of zones with room enough for movement but close enough to force conflict. 4x4 could work fine for a 1 on 1 chase, and 6x6 or more might work for huge fiascos.
What You Can Do on Your TurnShake PursuitShaking Pursuit is a special action only available to the quarry. Choose a difficulty and roll Drive against it, describing the insane risks you’re taking to escape your pursuers. If you fail to beat your chosen difficulty, you take chase stress equal to the degree of failure.
The benefit of taking the Shake Pursuit action is that each one of your pursuers must now roll Drive against the difficulty you chose, -1 difficulty for each zone between you and them. Failure inflicts chase stress to their vehicles equal to the margin of failure. In this way, one skilled quarry can evade multiple lesser pursuers without having to target each opponent individually.
If a pursuer beats both the chosen difficulty and their quarry’s own effort, they may move 1 zone. This does not count as a supplemental move. If the pursuer was already in the same zone as their quarry, they inflict chase stress on their quarry equal to the margin of success between their roll and the quarry’s roll.
As the quarry, therefore, you want to choose a difficulty low enough for you to beat, but not too low, else your pursuers will easily beat it as well, giving them a chance to beat your roll and gain on you. Plus, you don’t want to be too far away from your pursuers when you attempt to shake them, or else they’ll have time to prepare and your maniacal driving won’t be as effective (represented by the difficulty decreasing over intervening zones).
ManeuverManeuvers generally work as normal, although the GM should take into account the ever-changing environment in a typical high-speed chase when deciding if a given Aspect is fragile or sticky.
AttackTL;DR version. You can shoot another vehicle from one zone away, and you can ram them if you’re in the same zone.
Ram / Trading Paint / P.I.T. / Sideswipe (same zone only)You ram your vehicle into your target. Roll Drive to attack (modified by Body). Your opponent defends with Drive (also modified by Body). On a successful hit, you deal chase stress (if using durability stress, it does durability stress) equal to the shifts.
Optional: Use the difference in the two vehicles’ Body as a Weapon value, or , if your opponent’s vehicle’s Body is greater, apply that as Armor value. Motorcycles should not ram buses.
Shoot the Car (0-1 zone away)You make a ranged attack on the opponent’s vehicle. This usually is a Guns roll, but it might be Discipline if it’s a lightning bolt or something. The opposing driver avoids the attack with Drive. We generally even out the would-be penalties for firing from a jostling, speeding vehicle with the would-be bonuses to hit a large vehicle.
If the shooter is also driving, don’t forget the -1 supplemental action penalty.
Optional: The target’s Drive roll is restricted by Speed, this will make it a little easier to hit slower trucks and the like.
Shoot the Driver (0-1 zone away)If you’re shooting your opponent’s vehicle and beat their defense by 3 or more, you may apply that attack to the driver or a passenger.
Optional: Stress inflicted should probably be counted as if the defensive Drive roll was 3 higher, else every attack 3 points over the victim’s defense will be some sort of devastating headshot. Or you can reward the good rolling/FP expenditure and apply the full margin of success. It’s messier but it’ll resolve the conflict faster.
Shoot the Tires (0-1 zone away)Shooting out the tires is something best handled as a sticky Maneuver or as a Consequence of stress inflicted.
BlockBlocks in chases work pretty much like blocks everywhere else in the rules.
MoveMovement works like normal, except you roll Drive instead of Athletics.