Sensors in vehicles can improve highway capacity by 43 percent while sensors equipped with vehicle-to-vehicle communication can increase capacity by 273 percent.

Research shows that sensors and vehicle-to-vehicle communication both help increase highway capacity while reducing the severity and frequency of collisions.

Date Posted
03/31/2015
Identifier
2015-B00985
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Highway Capacity Benefits from Using Vehicle-toVehicle Communications and Sensors for Collision Avoidance

Summary Information

Several automobile manufacturers are offering assisted driving systems that use sensors to automatically brake automobiles to avoid collisions. Before extensively deploying these systems, it should be determined how they will affect highway capacity. This paper discusses a comparison of highway capacity when using sensors alone and when using sensors and vehicle-to-vehicle communication.

Methodology



A formal analysis was conducted that set out to find safe following distances for vehicles utilizing sensors, vehicles utilizing sensors in conjunction with vehicle-to-vehicle (V2V) communication, and vehicles that have neither of these technologies. In turn, those distances were used to estimate highway capacity.

The following distance for vehicles with sensors was calculated from its perception-reaction time (assuming the worst-case scenario) and the difference in the deceleration rate between itself and the preceding vehicle. Unlike the vehicles with sensors, communicating vehicles did not have to assume worst-case deceleration rates and could collectively decide on a group deceleration rate before an emergency stop. Like the vehicles with sensors, communicating vehicles maintained the safe following distance to its preceding vehicle. However, calculating the safe following distance of communicating vehicles was particularly reliant on whether or not its nearby vehicles could also communicate.



Results:



The study found that both vehicles with sensors and V2V communication help decrease the average safe inter-vehicle distance. Thus, both of these technologies can help increase highway capacity, but with vehicles communicating with each other providing a much higher percentage of improvement than vehicles with just sensors.



Safe Following Distances:

  • All manual vehicles- 30.56 meters.
  • All vehicles with sensors only- 19.91 meters.
  • All communicating vehicles- 5.03 meters.



Highway Capacity:

  • All vehicles with sensors only- ~43 percent increase.
  • All vehicles using both sensors and V2V communication- ~273 percent increase.



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