The present invention helps a driver steer a vehicle while backing up a trailer. A trailer being pushed wants to turn around and be pulled (i.e., to jackknife). To compensate for this instability, the driver must skillfully control his steering to cause the trailer to alternately move to be pulled from the opposite side thereby repeatedly crossing the centerline of the pushing vehicle. The moment when the trailer crosses this centerline is the moment of greatest instability and the position in which the driver would most desire to have the trailer travel. A pointer indicates in what direction the trailer is presently being directed; to backup the trailer, the driver turns the vehicle's wheel such that the pointer is kept pointing in the direction of the intended trailer destination. The present invention can be adapted to most vehicle and trailer combinations with minimal cost and complexity.