| Road alignment has important implications on traffic accidents. Based on the data of two mountainous roads, by the regression analysis, the correlations between horizontal and vertical alignment and the accident rate were studied and concluded.First, through research in the past, using CCR (Curvature Chang Rate)as curve parameter. According to samples divided by the curve, correlation between the accident rate and the CCR of horizontal curve is obtained. The CCR of upward N (N=0.25, 0.5, 0.75, 1, 1.5) km from the accident location, is defined as the horizontal parameters indicator and the correlation between the accident rate and the CCR indicator of upward N km can be researched.The second, together CCR to the length of the straight line before the curve(L), the correlation between the parameter A = CCR×L and the accident rate can be researched.The third, each curve for the samples, based on the horizontal and vertical alignment road safety research, calculated on the 3km average profile value and the 0.5km CCR value, determining its security level, which reflects the road safety situation. In addition, togetherCCR to the vertical slope parameters——3km average profile(i), the correlation between thecomposite parameter C = CCR×i and the accident rate can be researched.By the regression analysis, some results have been obtained as follows:(1) The CCR indicator of upward N km is superior to the CCR indicator of horizontal curve; 0.5km CCR and the accident rate showed the relevance of the second parabola and the correlation between the accident rate and 0.5km CCR is most significantly; when the 0.5km CCR is in between 0.002 and 0.003, the accident rate is minimum.(2) Parameter A and the accident rate showed the relevance of the second parabola . (3) Using the 3km average profile value and the 0.5km CCR value to determine the security level of road, which match the actual distribution of the accidents. Parameter C and the accident rate showed second parabolic relevance.
|
PDF Full Text Request