Abstract: In order to analyze the probability that the speed was greater than the speed limit value at an accident section, a method was worked out based on the sub-interval technique. In this new method, every input parameter was divided to many sub-intervals, and then all sub-intervals of different parameters were combined to form many sub-domains.Then, the accident reconstruction model would be Taylor expanded in each sub-domain and the upper and lower bounds of the reconstruction model could be calculated, and the sub-accident reconstruction velocity interval can be obtained.Finally, the number of sub-intervals of which the upper bound of the sub-accident reconstruction result interval was lower than the speed limit value and the number of sub-intervals of which the lower bound of the sub-accident reconstruction result interval was greater than the speed limit were all counted, and then the frequency of the later was recorded as the probability that the reconstructed velocity was greater than the speed limit value.Results of two numerical cases show that all results obtained by using the proposed method are almost the same as results obtained by using the Monte Carlo method, and no assumption should be made in the proposed method.Finally, a true collision accident was given to show the application of the proposed method. The results show that the probability of speed which is greater than the speed limit value at an accident section is 53.7%.

Key words: accident reconstruction, vehicle velocity, sub interval, probability, speed limit value