Citation

Yang HZ, Hu QY, Xu JL. J. Traffic Transp. Eng. (Xi'an, Shaanxi) 2010; 10(3): 10-16+40.

Copyright

(Copyright © 2010, Chang'an Daxue)

DOI

unavailable

PMID

unavailable

Abstract

The spatial and temporal distribution of traffic accidents and the distribution of vehicle types were counted for long-steep downgrade sections of expressway. The conditions of tested road sections and the causes of traffic accidents were analyzed. The running speeds of cars on expressway were surveyed by section observation method, and their running speed prediction model was formulated. The temperatures of brake drums for trucks were measured by DHS-130XL infrared observing instrument, and their temperature predict model was set up. The definition of long-steep downgrade was proposed. The indices of average longitudinal slope were determined, and the reasonable average longitudinal slope lengths of long-steep downgrade sections were determined. The safety design and evaluation method of long-steep downgrade were put forward. Analysis result shows that for long-steep downgrade sections, the main reasons of traffic accidents are overspeed and brake failure, the running speed can be used as the safety evaluation index for cars, while slope length and the temperature of brake drum for trucks. The temperatures of brake drum for security slope length, general safety slope length and maximum limit slope length are 200 C, 220 C and 260 C respectively. The amount of traffic accidents reduces by 42.3% and casualties reduces by 76.2% after setting some safe improvement measures at the sections, so the measures are effective.