BY PANOS PREVEDOUROS PHD – Urban underpasses are the key to central city congestion reduction given that there is no room to widen streets and there is no desire to build intrusive flyovers. Here is a short video that explains them.
The simulation screen-shots below show the before/after situation on Kapiolani Boulevard at its intersection with Date and Kamoku streets. The one lane per direction underpass visibly reduces congestion on Kapiolani Boulevard and allows for more green time to be allocated to the other sides of this complex intersection. This reduces their congestion and shortens the waiting time for the pedestrian crossings.