NE 12th Avenue: The Capacity of Two Approach Lanes at a Signal (4 vs. 3 Lanes)

The 12th Avenue Bridge is an overcrossing of I-84 in NE Portland. The history around the delineators on the bridge are part of the study the City completed to determine if there was sufficient capacity at the traffic signals to warrant restriping the existing four lanes on the bridge to three lanes that would accomodate space for a bike lane in the northbound direction of the bridge. The study was documented by BikePortland here and the final resolution was reported just this week after I gave an update on our performance reporting.

The Signals, Street Lighting, & ITS Division worked hard to synchronize the timing so that the capacity of the facility was maximized. We had an intern drive the corridor over 40 times to measure the before and after during the evening peak hours of traffic and more throughout the day to determine the morning and noon time conditions. All in all, it was a successful project for the City balancing the needs of all users with the interest in having the facility be safer for everyone.