Bus Lanes and Pre-signals with Transit Signal Priority: Domains of Application MASITE Meeting October 5, 2015 S. Ilgin Guler, Ph.D. Assistant Professor Civil and Environmental Engineering Pennsylvania State University iguler@engr.psu.edu Eleni Christofa, Ph.D. Assistant Professor Civil and Environmental Engineering University of Massachusetts Amherst christofa@ecs.umass.edu 1
Motivation Transit preferential treatments can improve transit operations and transit system reliability. These treatments are not always feasible due to financial and space constraints. They often come at the cost of additional delays for the other users of the system. 2
Background Priority in Space (Geometric) Dedicated bus lanes Bus Lanes with Intermittent Priority Queue jump lanes Priority in Time (Transit Signal Priority (TSP)) Passive priority strategies Active priority strategies (e.g., phase extension/advance) Priority in Time and Space Pre-signal Viegas, 2007 www.umn.edu www.mta.info 3
Dedicated Bus Lanes http://combo2600.com/del ayer y hoy/ commons.wikimedia.org www.mta.info www.transportdeals.co.uk www.streetsblog.org 4
Active TSP: Phase Extension (Green Extension)- Phase Advance (Red Truncation) Distance 2 Bus Stop 1 Bus Stop Bus Trajectory Time 5
Active TSP: Phase Extension (Green Extension)- Phase Advance (Red Truncation) Distance 2 Phase Advance Bus Stop 1 Phase Extension Bus Stop Bus Trajectory Time 6
Pre-signal: Example Configuration
Pre-signal: Example Configuration When no bus is present: Pre signal Dedicated Bus Lane Main signal
Pre-signal: Example Configuration When no bus is present: Pre signal Dedicated Bus Lane Main signal
Pre-signal: Example Configuration When no bus is present: Pre signal Dedicated Bus Lane Main signal
Pre-signal: Example Configuration When bus is present: Pre signal Dedicated Bus Lane Main signal
Pre-signal: Example Configuration When bus is present: Pre signal Dedicated Bus Lane Main signal
Pre-signal: Example Configuration When bus is present: Pre signal Dedicated Bus Lane Main signal
Pre-signal: Real-world implementation in Zurich, Switzerland https://www.dropbox.com/s/7hpastdiju6c7ee/shortclip.wmv?dl=0
Research Question What are the domains of application of these different transit preferential treatments such that total person delay is minimized? Parameters to be taken into account: Ratio of bus to auto passenger occupancy Auto demand on the priority approach Auto demand on the cross-street approaches Green ratio of priority approach 15
Methodology Objective: Minimize total person delay at the intersection Assumptions: Isolated signalized intersection Undersaturated traffic conditions 16
Methodology Approach N Cumulative Number of Vehicles (Approach N) ii i ii i q 2 s 2 Approach W i ii iii 1 2 1 2 C C Ti i) No bus ii) Phase advance - red truncation (bus on approach N) iii) Phase extension - green extension (bus on approach W) Cumulative Number of Vehicles (Approach W) q 1 iii i ii s 1 i ii iii 1 2 1 2 C C Ti
Scenarios Compared 1. Mixed lanes with green extension and red truncation 2. Dedicated bus lane with green extension and red truncation* 3. Pre-signal with green extension and red truncation at the main signal http://www.bikewalklincolnpark.c om/2011/11/bike lanes buslanes democracy in.html www.telegraph.co.uk www.th.gov.bc.ca 18
Generic Intersection Maximum Green extension/red truncation= 15 sec Cycle length = 90 sec Priority Approach Crossstreet Approach 19
Sensitivity Analysis with respect to Auto Demand and Passenger Occupancy Assumption: all approaches have the same demand Auto Demand per Approach [vph] 300 950 1600 Ratio of Bus to Auto Passenger Occupancy 1 50 100 Mixed Lanes with TSP Pre-signal with TSP 20
Sensitivity Analysis with respect to Auto Demand on Priority and Cross Streets Assumption: bus to auto passenger occupancy = 30 Auto Demand on Cross-Street [vph] 300 950 1600 Auto Demand on Priority Approach [vph] 300 950 1600 Pre-signal with TSP Mixed Lanes with TSP 21
Sensitivity Analysis with respect to Auto Demand and Green Ratio Assumptions: all approaches have the same demand ratio of bus to auto passenger occupancy = 30 Green Ratio for Priority Approach 0.30 0.45 0.90 Auto Demand per Approach [vph] 300 950 1600 Mixed Lanes with Pre-signal with TSP TSP 22
Conclusions When pre-signal is combined with TSP, it performs similar to a dedicated bus lane in terms of bus delay. The higher the ratio of bus to auto passenger occupancy the higher the need for pre-signals with TSP. The higher the auto demand on the priority approach, the lower the need for pre-signals with TSP. The higher the green ratio of the priority approach, the more likely it is that the mixed lanes with TSP will be minimizing the total person delay at the intersection. The proposed method can be used to assess investment decisions for transit agencies and towns that are interested in improving their transit operations. 23
Next Steps Perform a similar analysis incorporating the use of intermittent bus lanes and queue jump lanes with and without TSP Investigate the domains of application for: Oversaturated conditions Arterial signalized networks 24
Questions? S. Ilgin Guler iguler@engr.psu.edu Eleni Christofa christofa@ecs.umass.edu www.transportdeals.co.uk 25