PURPOSE: To surely wake up a driver during drive by stimulating the hearing of the driver, and concurrently letting him feel deceleration.

CONSTITUTION: A chime 11 periodically gives fairly light sound in order to make sure of being waken on the part of a driver, and buzzer 12 also provides unpleasant sound in order to wake up the driver. The grasping force of a handles 38 by the driver is detected by touch sensors 36 and 37 fitted onto the handle 38 of a truck 10 so that time from starting the operation of the chime 11 to time when the operation is suspended by the driver is measured by a timer 47. The buzzer 12, a volume adjusting means 13 and an emergency braking means 38 by a controller 41 are controlled in order based on a signal from either one of each touch sensor 36 and 37 or the timer 47 or signals from both each touch sensor and the timer.