摘要: |
Traffic crash data from 2010 to 2014 were collected by Mississippi Department of Transportation (MDOT) and extracted for the study. Three tasks were conducted in this study: (1) geographic distribution of crashes; (2) descriptive statistics of crash data; and (3) probability analysis of crash factors. Geographic Information System (GIS) was applied to show the historical crash data statewide distribution, crash distributions on primary and secondary road segments in the public road system, and crash distribution in MDOT maintenance districts. The results show a similar distribution pattern in the three crash severities in Mississippi as in other states, i.e., property damage only counts the highest, injury the second, and fatality the lowest. It also shows that large numbers of the crashes happened on specific locations and there are high crash frequencies on highway segments in Jackson metropolitan area, Hattiesburg urban area, and Gulf coastal metropolitan area. Based on the historical data and geographic distribution results, three comparison scenarios were investigated in Scenario I between US 49 and MS 25, Scenario II for statewide urban and rural areas, and Scenario III for coastal urban and hinterland urban areas. Crash data descriptive statistics for the three scenarios were initially achieved in SAS and the characteristics of differing crash frequencies and severities with the three scenarios were calculated. In order to estimate the probability of each possible causing factor to the crash severity level, the Type III analysis of variance (ANOVA) approach was adopted to assess the significance level of each crash factor, and the multinomial logit model approach with maximum likelihood estimate was applied to conduct the probability analysis and evaluate the significance of each crash factor. The strategies that may potentially decrease the crash frequencies at crash severity levels were discussed based on the probability analysis results. |