ACC works like that, and people complain it's a joke, you have to spend a huge amount of time driving alongside another car without contact to farm SR. And it actually causes collisions because it means nobody wants to drive away from other cars in a race, because you're not achieving anything if you aren't really close to another car.
True.
I would suggest:
- give SR Down (-3 SR) for going off track, touching a wall, spinning out.
- give minor SR up (+0.5 SR) per clean sector as is now
- give SR Up (+3 SR) per clean lap
- give SR Down (-3 SR) for contact with another car
- give minor SR up (+1 SR) for losing a position contact free (max 3 per race not to encourage pulling over and letting everyone pass to farm SR)
- give SR Up (+3 SR) for contact free overtake of similar DR rank or higher (max 3 per race not to make starting last the best way to farm SR or playing leap frog)
This will mitigate the negative effect of avoiding a car and losing SR, while rewarding clean driving.
The SR Down for going off track is absorbed by the SR up for the contact free pass. Yet with a limit of 3, don't make it a habit.
If you spin out or run off track while avoiding a car and get passed by half the field, -3 SR for spinning out, 3 x +1 SR for getting passed without contact.
So you have some leeway to avoid cars instead of making it equal or better to simply hit them.
Keep the ignoring track limits penalties though, pass on the grass should still be discouraged even if it's to avoid another car in trouble. Yet if it is to avoid that car (and you thus pass it) you won't lose SR. And if you slow down while avoiding, the shortcut penalty won't trigger either.
This still won't stop the yoyo effect, drop SR, easier race, pole to flag victory, back to SR.S. Yet combined with better matchmaking (max 3 SR groups) and no more DR resets those easier races to farm SR back should be a thing of the past.
That leaves the issue of simply driving behind to farm SR in exchange for DR. Higher DR should come with more rewards instead of more punishment. Higher payouts, and smaller contact trigger before penalties and SR Down contact shows. It's upside down now where low DR can hit high DR and high DR gets the most blame. Minor contact should be discouraged at low DR, yet at the blistering pace A+ drives at, minor contact is usually fine and both drivers have enough control to anticipate and stay on the road. The problem of high DR bowling low DR out of the way won't be effected since the force with that speed difference will still be high enough to trigger penalties. Make it rewarding to maintain high DR instead of a curse in daily SR.S races.
Perhaps with all that we don't need time penalties for contact and the SR system will be able to sort the drivers more effectively. Of course time penalties for straight up punts (the easy to detect cases) should still be there as well as -10 SR for such infractions. Contact with very large force, use
@Voodoovaj's suggestion to look who is more aligned with the racing line and/or more within the speed range for that section of track at the moment of collision. Dive bombs and revenge punts should be easy to detect.
If the above works, it can be further refined by looking at leaving space requirements to stop people gently pushing each other off the road or against a wall. Not that hard to detect either, 2 cars side by side with less than a foot of space in between, one car goes off or against a wall, other car was not leaving enough room. SR Down can trigger while not even touching a car, crowding off track penalty. But that's for later.