Night Speed Limit Value of Roadway Segment with Pedestrian Crossing
|School||Harbin Institute of Technology|
|Course||Traffic and Transportation Engineering|
|Keywords||night limit speed visual recognition distance pedestrian crossing cross-street pedestrians illumination intensity|
In recent years, the number of night traffic accidents in urban streets has beenincreasing and the casualty of cross-street pedestrians shares about ten percent ofthe total traffic accident casualties. Night traffic accidents have greatly threatenedcross-street pedestrians’ safety with many significant features such as largecasualties, strong destruction and high occurrence probability. The main reason ofnight traffic accidents is the higher speed, less traffic volume and significantdecrease of illumination intensity at night vision recognition distance of drivers isshorten and the time for drivers to take safety measures is not enough. Thus,research on night speed limits of roadway segment with pedestrian crossing can bepractically significant.Firstly, the paper does some surveys on a part of drivers and road traffic inHarbin at night; defines the test conditions, and tests drivers’ night visionrecognition distances to cross-street pedestrians under different lighting conditionsand driving speeds. These data or information is important to later analysis.Secondly, this paper compares the differences of visual recognitionenvironments from four aspects of lighting conditions, traffic volume, vehiclespeed and pedestrian crossing and analysis the differences of drivers’ visualrecognition distances with different speeds and clothing colors between day andnight. Based on the data, analysis of the variation of drivers’ visual recognitiondistances along with the change of driving speed in different lighting conditions isconducted and night visual recognition distance-speed model in different lightingconditions is established. According to the speed survey, this paper divides nightdriving speeds into low, medium and high grade and analysis the variation ofdrivers’ visual recognition distances along with the change of illuminationintensity at different driving speeds, and then establish night visual recognitiondistance-illumination intensity model at different driving speeds.Finally, establish night visual recognition distance-speed-illumination intensitymodel. Based on the relation between safety-stop distance and visual recognitiondistance, found the safety driving conditions. According to the critical safe drivingconditions, deduce the limit speeds-illumination model and illumination-designspeeds model to do some case analysis. At last, give some advices on street lightlayout of pedestrian crossing.