I like the system I have for chases in my game.
Basically it has to do with initiative. The prey always has initiative because he is setting the course and the predator in the chase has to react to him.
Prey Actions
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They can make a driving/piloting roll and a gunnery roll if they have rear guns. If their driving/piloting roll (driving/piloting + maneuverability + d20) is as high as the terrain DC then it doesn't get into an accident. As long as there is no accident then the result of the Roll is the DC to stay with that ship. If predator misses by 5 then they don't get a shot at the prey at all. If they miss by 10 then the prey can decide to reverse on the predator and change places. If the predator misses by 15 then the prey can loose them – as long as there is some cover to loose them in (ie doesn't work in open water or space). [/FONT]
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A prey can go evasive. This is the same thing as aborting to dodge is for a character. While you are evasive you are moving too erratically to shoot back (you may be throwing your passengers around as well). It lasts through your next turn and until the beginning of the turn after that one. [/FONT]
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Faster Prey[/FONT]
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If the prey is significantly faster then the predator then the chase is up to the prey. Once the prey is in more open then tight terrain it can choose to end the chase on their turn. Their movement will take them out of range fairly quickly. [/FONT]
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Prey Criticals[/FONT]
- [FONT=Verdana, sans-serif]Switch to become Predator[/FONT]
- [FONT=Verdana, sans-serif]Increase Terrain Difficulty for Predator[/FONT]
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Predator Action[/FONT]
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Predator makes driving/piloting roll (Driving/Piloting + Maneuverability + Size Penalties + 10). Pilots get a bonus or penalty based on the size of the vehicle they are trying to chase. If the target vehicle is larger then add the difference in size as a bonus to their rolls. If it is smaller then subtract it. You don't have to stay as close to a larger vessel to stay with it. [/FONT]
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As long as the Predator's roll is not more then 5 below the prey they will keep up with them and can shoot at them. If they don't then they can't fire at them accurately (they can fire wildly for free but no roll is made). If they miss by 15 then they loose then. If they don't even make the terrain DC then they stop where they are. This is not necessarily a crash. They are just blocked by the terrain and can't keep up. If they botch then they run in to something. [/FONT]
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If the predator beats the prey's roll then the predator's group gets the margin of success as a bonus for their attacks that action. They can make an attack as their second action or another character's action. In a fighter aircraft it would be the predator's pilot's gunnery roll. In a larger craft it could be a separate gunner. [/FONT]
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Faster Predator[/FONT]
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If the predator is significantly faster then the prey then they can not be lost in anything more open then tight terrain. It requires the tight terrain to get lost in for them to have a chance to get away. They do not loose them on a 15. [/FONT]
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If the predator is an aerial vehicle following a ground vehicle then it can only loose the vehicle if there is somewhere for it to travel under cover for a while. However the restricted attack rolls still apply. The ground vehicle can evade enough to make it hard to hit from the air. [/FONT]
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Of course if the predator is too much faster then the prey it only counts as a strafe instead of as a chase. [/FONT]
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Predator Criticals [/FONT]
- [FONT=Verdana, sans-serif]Increase Terrain Difficulty for Prey by crowding[/FONT]
- [FONT=Verdana, sans-serif]Decrease Terrain Difficulties for gunnery actions and passengers[/FONT]
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Keep up![/FONT]
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Sometimes it is all you can do just to hang on! Instead of having a gunnery action or even driving to get better positions you focus on making it through the terrain and not loose them. Reduce the DC by -5. This action is often taken by everyone else but the lead predator in a large chase. [/FONT]