Traffic Signal Control Optimization with Transit Priority for Conflicting Transit Routes

Transcription

1 Traffic Signal Control Optimization with Transit Priority for Conflicting Transit Routes Eleni Christofa PhD Candidate University of California, Berkeley 16 th UCTC Student Conference University of California, Irvine April 1, 2010

2 Motivation 2

3 Literature Review: Transit Signal Priority (TSP) Strategies Passive Priority Strategies Adjustment of offsets Additional green time for transit phases Reduction in cycle length Active Priority Strategies Phase extension (green extension) Phase advance (red truncation) Phase insertion Phase rotation Fixed dwell times for transit vehicles Do not take advantage of new technologies Not traffic responsive 3

4 Phase Extension Phase Advance Distance 2 Bus Stop 1 Bus Stop Bus Trajectory 4 Time

5 Phase Extension Phase Advance Distance 2 Phase Advance Bus Stop 1 Phase Extension Bus Stop Bus Trajectory 5

6 Literature Review: TSP Strategies Passive Priority Strategies Adjustment of offsets Additional green time for transit phases Reduction in cycle length Active Priority Strategies Phase extension (green extension) Phase advance (red truncation) Phase insertion Phase rotation Fixed dwell times for transit vehicles Do not take advantage of new technologies Not traffic responsive Loss of Signal Coordination (potential) Oversaturation of vehicle movements (side-streets) Not conditional TSP 6

7 Literature Review: Signal Control Systems with TSP SCOOT SCATS Real-time Signal Control Systems ATSPS California, PATH PRODYN UTOPIA SPPORT Centralized TSP LADOT No systematic treatment of conflicting transit routes Not conditional priority Vehicle-based optimization of signal settings Lack of network implementation 7

8 Research Question How should traffic signal control systems be designed so that they provide: priority to transit vehicles traveling in conflicting directions, while minimizing the impact on general traffic in signalized arterial networks? 8

9 Objective Network-wide traffic responsive signal control system with transit priority Impact on general traffic is minimized Transit vehicles traveling in conflicting directions Conditional priority based on schedule delay & occupancy Incorporation of new technologies Evaluation of cost-effectiveness 9

10 Isolated Intersection: Study Site 10

11 Isolated Intersection: Formulation Min a 1 d subject to: a a (Person Delay) i I (Minimum Green) N j i 1 G i G G i C (Constant Cycle Length) B b 1 j min d b b ο α ο b A B d α : occupancy of auto α [pax/veh] : occupancy of transit vehicle b [pax/veh] : total number of autos served during cycles T or T+1 : total number of transit vehicles served or arrived during cycle T : control delay for auto α [sec/veh] d b : control delay for transit vehicle b [sec/veh] G i : green time allocated to phase i [sec] G j min : minimum green time allocated to lane group j [sec] C : cycle length [sec] I j : set of phases that can serve lane group j N : number of phases in a cycle 11

12 Isolated Intersection: Preliminary Results (1hr of operation) o o a b 1.25[pax/veh] 40[pax/veh] Auto Delay (pax-hrs) Bus Delay (pax-hrs) Total Delay (pax-hrs) Base Case Scenario Scenario 1: Vehicle-based Optimization Scenario 2: Person-based Optimization % Improvement in Person Delay between Scenarios 1 & 2-5.9% +38.3% +12.3% 12

13 Isolated Intersection: Preliminary Results 40[pax/veh] o b 13

14 Isolated Intersection: Preliminary Results Initial Auto Volumes 14

15 Future Work 1. Isolated Intersection Other TSP Strategies Oversaturated conditions Evaluation 2. Arterial/Grid Network Optimization process Evaluation 3. Policy Implications Improvements of transit operations increase in ridership Trade-off between efficiency in traffic and transit operations 15

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