Abstract:
No-passing zone crashes constitute a sizable percentage of the total crashes on two-lane
rural roads. A detection and warning system has been devised and implemented at a no-passing
zone site on route 114 of Southwest Virginia to address this problem. The warning system aims
at deterring drivers from illegally conducting a passing maneuver within the no-passing zone
area. The violating driver is warned in real time to stop the illegal act. This system is currently
operational and its main function is to warn the no-passing zone violator. The aim of this
research is to extend the warning system to the opposing vehicle in the same lane of the
persistent violator in order to avoid crashes caused by the illegal maneuver that is taking place at
a crest vertical curve of the two-lane rural road.
In order to test the new system prior to its physical installation, a computer simulation has been
developed to represent the real world violation conditions so that a better understanding of the
problem and its varying scenarios would be achieved. The new simulation, which is the focus of
this thesis, takes advantage of an existing simulation developed earlier to replicate only the
illegal maneuver without giving any warnings to the opposing vehicle. The new program
simulates the outcome of deploying a warning sign to the opposing driver for crash avoidance purposes assuming that all violators persist to pass the vehicle ahead.
More than 712,000 computer runs were conducted to simulate the various possible outcomes including the sensitivity analysis. A critical comparison was made between the previous system that warned only the violating vehicle and the current program that warns both the violator as well as the opposing vehicle. The results indicate that warning the opposing driver would reduce the rate of unavoidable crashes by approximately 11% in the east direction and 13.25% in the west direction.
