Driver Turn-Taking Behavior in Congested Freeway Merges

Data from four merge locations in northern California and Toronto, Canada unveil a notable feature of driver turn taking. We have observed that queued vehicles from the on-ramp and freeway traffic streams enter a congested merge in some (nearly) fixed ratio, independent of the merge outflow. Drivers in competing traffic streams thus enter the merge by adopting some definite turn-taking behavior and this behavior is not influenced by the severity of the exogenous flow restriction from downstream. The findings validate part of an existing theory of merging traffic and should be considered when developing any new such theories.