LSU Civil Engineering Researchers Publish Paper on CAV Impact on Road Networks
August 7, 2024
BATON ROUGE, LA – LSU Civil Engineering researchers have examined the effects of Connected and Autonomous Vehicles (CAVs) on traffic operation and safety at full-cloverleaf interchanges. What they’ve found is that the more CAVs present on this type of interchange, the greater the reduction in travel time, improved traffic flow, and enhanced safety.
The study, conducted by LSU Civil Engineering Assistant Professor Hany Hassan and his graduate student, Nischal Khadka, was recently published in a paper titled, “Exploring the Effects of Connected and Autonomous Vehicles on Traffic Safety and Operation at Full-Cloverleaf Interchanges,” in the Journal of Transportation Safety & Security.
“The study found that higher [presence] of CAVs led to significant reductions in travel time across on-ramps, off-ramps, and weaving segments,” said Hassan, who is lead author on the paper. “For instance, travel times decreased by 46%, 41%, and 32% at the three interchanges under investigation when moving from the base scenario (no CAVs) to 100% CAVs. This means that commuters and travelers could experience shorter and more predictable travel times, leading to less time spent in traffic.
“Safety evaluations…demonstrated considerable declines in the number of vehicle conflicts with increases [in CAV usage], averaging reductions of 32%, 26%, and 20% at the three interchanges from the base scenario to [100% CAV presence], respectively. This suggests that CAVs can significantly reduce the likelihood of traffic collisions, making roads safer for drivers, passengers, and pedestrians.”
Similar trends applied to improved traffic flow, Hassan added, as CAV presence increased.
In the paper, Hassan and Khadka assess the influence of various Market Penetration Rates (MPRs)—the percentage of CAVs present on roadways—on travel time, queue length, and conflict points considering various weaving lengths—the segment of roadway where vehicles merge onto the highway from a loop ramp immediately before other vehicles exit the highway to navigate another loop ramp—using VISSIM.
VISSIM is a microsimulation traffic tool that is used to simulate road networks and the vehicle behavior and interactions on them, thereby capturing the dynamics of various transport modes and pedestrian movements.
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