Abstract
Freeway merge conflicts contribute significantly to freeway congestion. With the capabilities that will be available in an IntelliDrive environment, which enables vehicle-to-vehicle and vehicle-to-infrastructure communications, new approaches to managing freeway merges are possible. In this paper, an enhanced IntelliDrive enabled lane changing advisory algorithm was developed with a variable gap size concept. This algorithm first calculates anticipated lead–lag gap sizes with the equations of motion prepared for a car and a truck and for three vehicle dynamics (accelerating, maintaining current speed, and decelerating). The algorithm then provides lane changing advisories to freeway main-line vehicles (selected on the basis of the calculated variable gap sizes) to create more space within the ramp merging area. Evaluation conducted with a VISSIM microscopic traffic simulation model of a freeway network in Virginia showed that the proposed algorithm has the potential to address freeway merge conflicts. The maximum operational improvement observed was 6.4% higher average speed in the freeway main line within a merge area. Up to a 5.2% reduction in emissions was achieved. Further analysis conducted in terms of the sensitivity of algorithm performance to driver compliance rates suggested that a very high compliance rate (90% or higher) was necessary for the proposed algorithm to work as intended.
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