Huaguo Zhou

Application of Access Management Techniques to Reduce Wrong-Way Driving Near Interchange Areas

Past studies indicated that interchange configurations, access control, and geometric design are related to Wrong-Way Driving (WWD) and minor ramp geometric changes can be effective in reducing the number of wrong-way entries onto freeways. In this paper, access management techniques and geometric elements, which are capable of discouraging wrong-way maneuvers, are identified and discussed. Additionally, every aspect of these elements and their relationship to WWD is investigated. These geometric elements include interchange types, exit ramp terminals, frontage roads, raised medians, channelizing islands, and control radius. The aforementioned elements should be given a special consideration during the design stage of interchanges and intersections.

A Sensitivity Analysis of Crash Modification Factors of Access Management Techniques in Highway Safety Manual

Access management involves control, planning, and coordination of access along roadways to provide safe and efficient operation of transportation networks. According to existing literature, reducing conflict points and improving traffic safety are the main goals of access management techniques. Increase in traffic volumes and rapid growth of roadway networks have made these efficient techniques as a crucial part of roadway planning and design process. Some of the access management techniques employed in the recently published Highway Safety Manual (HSM) include: median treatments, traffic signal spacing, auxiliary lanes, corner clearances, driveways, U-turns as alternatives to direct left-turns, and frontage roads. Moreover, the Crash Modification Factors (CMFs) of these techniques, as estimators of the actual safety effect of countermeasures, are utilized in the HSM predictive methods to approximate the potential changes in crash frequency and severity after treatment implementation. The results of this study provide transportation agencies, practitioners, and decision-makers with a better understanding of how the HSM methods quantify the safety effects of access management techniques on different roadways. This is accomplished by providing output in the form of tabulated ranking of the impact of access management parameters for three roadway facilities defined in the HSM using the graphical method of sensitivity analysis.