If someone wants to save a life, an economic incentive is not required. Creating an incentive might lead to problems, such as autos picking up victims who are in no shape to be shipped in an auto. But I suppose there is some research backing this action.

Removing legal hassles is far more important. I have helped accident victims often, and have never faced hassles from the police. Auto drivers would be more susceptible to harassment by the cops. If an auto driver knows he will not be harassed, he is a lot more likely to help. Expediting the legal framework around that is most important.