A vehicle electric drive system has an internal combustion engine which
drives an electric generator. The generator powers a motor which drives
the wheels. The system has operator controls including a speed control
member movable from a zero speed position to a high speed position, an
FNR direction control member having forward, neutral and reverse
positions. The system also includes a wheel speed sensor and an
electronic control unit. Upon startup, the control unit senses the
position of the direction control member, senses wheel speed, and senses
position of the speed control member. The controller prevents vehicle
operation if the direction control member is not in its neutral position,
or the sensed wheel speed is not close to zero, or the speed control
member is not near its zero speed position. The controller permits
vehicle operation if the direction control member is in its neutral
position, and the sensed wheel speed is close to zero, and the speed
control member is near its zero speed position.