Investigating multiplier effects created by combinations of transit signal priority measures on arterials

Transit signal priority (TSP) has proven to be a cost-effective solution for public transport vehicles at signalised intersections as it usually does not require substantial infrastructure upgrades, while improving bus travel time and reliability. Numerous studies have focused on the design and operation of TSP, while few have considered the optimum combination of TSP at a corridor and a network level. However, it is unclear whether the combination of TSP on an arterial or a network creates a multiplier effect on public transport benefits, i.e. benefits from providing TSP at multiple intersections are higher than the sum of benefits from providing TSP at each of those individual intersections. This paper investigates the effects of combinations of TSP measures on signalised arterials to establish if a multiplier effect exists. Results of a modelling test-bed reveal that combinations of TSP measures on signalised arterials can create a multiplier effect on bus delay savings when signal offsets are optimised to minimise bus delays. The existence of the multiplier effect suggests considerable impacts of TSP on a network-wide scale.