摘要: |
Traffic speed is generally considered as a core issue in roadway safety. Many previous researches show that speed variance, not necessarily high speed, is associated with an increase in the frequency of crashes. And some factors might affect speed variance and further affect roadway safety performance, such as configurations of speed limits, characteristics of traffic volume, geometry of roadways, driver behaviors, and environmental factors. This research is trying to identify possible factors that could influence the speed variance on multilane roadways, especially for access design factors. Statistical models will be established to summarize relationships between speed variance and these factors. Data collection is performed for modeling, including speed data, geometry data, traffic data, control data and etc. Radar guns and a roadway video log surveillance system (RVLS) will be used to collect speed data, and other necessary data will recur to Florida Inventory Database. Besides the models basing on analysis of field data, another method is also conducted as an addition, by using traffic simulation, such as TSIS. The micro-simulation analysis can be further analyzed to obtain the models that specify the impacts of access management treatments and geometric design on traffic operational speed distributions, which could be used to support the findings from field data analysis. Finally, a guideline will be developed summarizing relationship between all contributing factors and speed variance, in order to improve safety performance. |