A computer includes a processor and a memory storing instructions executable by the processor to determine, for a host vehicle operating in a first operation mode, a first operation mode transition location based on a time to transition the host vehicle from the first operation mode to a second operation mode, a current speed of the host vehicle, and a distance from the host vehicle to an operation mode transition boundary location, to determine a second operation mode transition location that is a specified distance from the first operation mode transition location, the specified distance based on the current host vehicle speed, to transition from the first operation mode to the second operation mode upon reaching the first operation mode transition location, and to transition from the second operation mode to the first operation mode when the second operation mode transition location is between a current location of the host vehicle and the operation mode transition boundary location.