Andrew Nash

Document Type

Journal Article

Publication Date


Subject Area

operations - traffic, infrastructure - vehicle, infrastructure - bus/tram priority, infrastructure - bus/tram priority, infrastructure - traffic signals, planning - surveys, organisation - regulation, mode - bus, mode - tram/light rail


Zurich (Switzerland), Trolley cars, Transit vehicle operations, Transit priority, Transit buses, Trams, Traffic signal timing, Traffic signal settings, Traffic signal priority systems, Traffic signal preemption, Traffic signal phases, Traffic regulations, Traffic engineering, Traffic calming, Surveys, Settings (Traffic signals), Separate right-of-way, Preemption (Traffic signals), Local government officials, Interviewing, Implementation, Capital expenditures, Bus priority


Transit priority is an excellent way of improving transit system productivity and attractiveness although it is often neglected in favor of larger investments. Transit priority techniques and implementation are outlined, Zurich's transit priority program is described, eight transit priority implementation lessons from Zurich are presented, and Zurich's innovative traffic-signal transit priority system is summarized. A longer report that fully describes research results is the basis. Transit priority improvements are relatively low-cost ways to make transit systems work better by speeding up transit vehicles. Specific improvements include four categories: roadway improvements and traffic regulations, traffic signal priority, transit system operations, and separate right-of-way. These improvements may be implemented individually or in a comprehensive program. Comprehensive implementation is optimal but politically and institutionally difficult. Zurich has been successful in implementing a comprehensive transit priority program with impressive results. Implementation lessons from Zurich were identified through interviews and a survey of public officials. Key findings were the importance of support from public and elected officials (and the common underestimation by elected officials of their constituents' transit support), smart implementation techniques (not alienating the public), government organization to deliver projects, careful traffic engineering, simultaneous implementation of complementary programs (such as traffic calming), careful systems-level thinking, and leveraging needed organizational change through capital improvement funding. Zurich's traffic-signal transit priority system is an interesting example of reducing opposition to transit priority through technical innovation. The system provides transit priority without significantly affecting private vehicle traffic by adjusting signal timing and phasing to provide the right amount of green time for transit when needed.