Intermittent and Dynamic Transit Lanes: Melbourne, Australia, Experience

Document Type

Journal Article

Publication Date


Subject Area

operations - capacity, operations - traffic, infrastructure - vehicle, infrastructure - bus/tram priority, infrastructure - bus/tram lane, infrastructure - bus/tram lane, policy - congestion, mode - bus, mode - tram/light rail, mode - mass transit, mode - carpool


Variable message signs, Trolley cars, Transit, Trams, Traffic congestion, Traffic capacity, Public transit, Priority lanes, Melbourne (Australia), Mass transit, Local transit, Lisbon (Portugal), Intermittent bus lanes, In-pavement flashing lights, HOV lanes, Highway capacity, High occupancy vehicle lanes, Gridlock (Traffic), Dynamic message signs, Diamond lanes, Changeable message signs, Carpool lanes, Bus lanes


Segregated transit lanes are an efficient means of improving transit reliability and speed on shared urban roads. A major limitation of these lanes, however, is their impact on road capacity and traffic congestion. Intermittent bus lanes (IBL) are an innovative concept for addressing this limitation. IBLs include variable message signs and flashing lights embedded in the pavement that warn motorists to avoid transit lanes only when buses are coming. This approach prioritizes transit while limiting impacts on other road users. If feasible, this approach may substantially increase the scope of transit priority in cities. However, feasibility of IBL is a major concern. A trial was undertaken in Lisbon, Portugal, in 2005 and 2006. Although the results were promising, more practical experience with IBL is required to justify its widespread implementation. This paper reviews the performance of a variation on the IBL concept, the dynamic fairway (DF) adopted for trams in Melbourne, Australia. The system was initiated in 2001 and is still operational. The paper documents the world’s first practical, ongoing experience with IBL-DF operation. Future plans for a Melbourne bus-based IBL called the “moving bus lane” are also presented. Overall, the performance of the Lisbon IBL trial appears to be better than that of the Melbourne DF. However, the circumstances of the two examples were different, including the road configuration, transit mode, levels of congestion, and the newness of the technologies involved. Significantly, both applications found good driver compliance with transit lanes, suggesting the IBL-DF concept has practical performance benefits.