抄録
This manuscript presents changes in bottleneck capacity at a freeway diverge in Bangkok. This bottleneck was caused by an exit ramp queue moving upstream onto the freeway. Detailed traffic data from an expressway in Bangkok show that traffic states during bottleneck activation could be grouped into three states with different levels of capacity based on vehicle speeds on through-movement lanes and the rates of lane changing maneuvers near the off-ramp queue. Data also indicate that the transitions of traffic states were primarily caused by the changes in exit flows. The lower capacity was initiated by a more restrictive off-ramp flow that causes cut-through vehicles on the adjacent lane impeding through-movement traffic. Once relaxing the exit flow, impeding vehicles could move out of the adjacent through lane and higher capacity often restored. These findings also show how automatic off-ramp control strategies could generate higher bottleneck capacities through detecting traffic speeds on the freeway.
