Departure Angle and Approach Length of Truck Escape Ramp

Abstract:

The motion data about the motor vehicle driving into truck escape ramp for 144 times by 5 drivers were obtained by driving simulation on UCWin Road Ver.9. Then the adjustment length, time and the minimum turning radius were extracted on basis of the steering velocity indexes. An analysis was made of the correlation between the abovesaid three indexes and the operation speeds, departure angles. Then, the setting range of the departure angle and the approach length was proposed based on two step cluster analysis. Research result indicates that the departure angle of truck escape ramp should be within 5°. The maximum departure angle should be controlled within 12.5° and the super elevation must be set during approach of truck escape ramp. Adjustment time is selected as the design index of the approach length. The required time value is 6 s when the efflux angle is within 5° whereas the value is 9 s when the efflux angle is between 5° and 12.5°.

Key words:truck escape ramp; driving simulation; departure angle; approach length