A system includes a computer programmed to determine, along a nominal path to be traversed by a vehicle, a potential field representing a driving corridor for the vehicle. The computer is further programmed to identify a position of the vehicle relative to the potential field at a current time, and apply a torque to q steering column of the vehicle. The torque is based at least in part on the position. The potential field includes an attractive potential that guides the vehicle to remain within the corridor.