Width of Cross Section on Truck Escape Ramp Based on Driving Simulation

Abstract:

Under the circumstance that the cross section width of truck escape ramps is 4.5 meters, 7.7 meters, 9.0 meters, and 12.2 meters, fortyeight groups of motion parameters of motor vehicle driven onto truck escape ramp by 5 drivers were obtained by driving simulation UCWin Road Ver.9. Then, the minimum turning radius, adjusting time, steering angle amplitude, steering angular frequency, and the bending position were extracted using steering velocity index, steering wheel angle, and lateral migration rate. The correlation between the above five indexes and cross section width, operating speed and interaction of cross section width, and operating speed were analyzed by using two ways ANOVA. After that, the significant test of the five indexes at different cross section widths were analyzed by multiple comparison. The research result indicates that the minimum turning radius, steering angle amplitude and steering angular frequency of 4.5 meter cross section widths are significantly different from the other three groups. Errant vehicles are in sideslip risks when their operating speed just reaches 90 km?h-1 at the 4.5 m cross section width. At the same time errant it is difficult for the driver to drive the vehicle into the truck escape ramp successfully and the driver suffer from severe psychological tension. The bending position is prior to the starting point of the transition segment only when the cross section width is 12.2 meters. And the difference between bending position and transition starting point is more significant compared with the other three groups. The cross section width has a significant effect on adjusting time which has a significant differences at different widths. There exists a power function relation between adjusting time and cross section width. Comprehensive analysis shows that the cross section width of truck escape ramp should not be less than 7.7 m.

Key words:road engineering; truck escape ramp; driving simulation; cross section width; approach road