Managing Trams and Traffic at Intersections with Hook Turns

Abstract

Signalized intersections with trams in mixed traffic are problematic because of conflicts with traffic making opposing turns and the delays that they cause for trams. In Melbourne, Australia, an approach called a hook turn, used for more than 50 years, removes this barrier because turning traffic must wait in curbside lanes to make turns when signals for the side road turn green. This paper presents a review of the hook turn and explores operations and safety impacts. Hook-turn styles of maneuvers are in use for buses in Australia, traffic in China and the United States (Illinois), and bikes and motorcycles in several countries. In each case, hook turns relocate opposing turns to improve intersection safety and efficiency. Operational analysis of the traffic impacts of hook turns in Melbourne suggest that they act to reduce congestion because turning traffic does not delay through vehicles. In addition, 38% of drivers tend to avoid hook turns; that decision acts to increase intersection capacity. An analysis of tram delay suggests a savings of 11.25 s to 15.64 s per tram and of three to five trams being added to the fleet compared with the number needed in an operation without hook turns, or between Aust$15 million (US$12.9 million, in 2010 dollars) and Aust$25 million (US$21.5 million) in fleet capital costs. A series of safety analyses with crash data and conflict point analysis demonstrates that intersections with hook turns have better safety performance than conventional intersections. Hook turns act to improve intersection operations and safety with trams in the Melbourne context. However, challenges with driver understanding and compliance are major barriers to adoption of hook turns in other areas.