A little touch I noticed is the green light that flashes on the car when getting a pickup, but a lot of times I hardly notice I managed to get it because of how subtle it is.
When I tried racing with the front camera, however I noticed a more prominent effect with four lights around the screen. IMO I think this should also be on the 3rd person camera as well. The 2 small lights are too small to notice most of the time.
This could also be used as the possible indicator for being locked on to as mentioned before, but with a red color.
Attached are both examples and quick overlay on the 3rd person camera.