transit signal priority: managing expectations kevin n. balke, ph.d., p.e translink ® research...
TRANSCRIPT
Transit Signal Priority:Managing Expectations
Kevin N. Balke, Ph.D., P.ETransLink® Research Center Director
Texas Transportation Institute
Transportation Research Board MeetingWashington D.CJanuary 13, 2002
Presentation Outline
Transit Priority Theory Historical Perspective Future Perspective
On-going Applications Implementation Issues
Managing Expectations
Historical Perspective
Driver Judgment
“Contact closure”Detection
“Preempt”Signal Operations
Intelligent Traffic Signal Priority
Transit Vehicle Knows …. Where it is Whether it needs
priority Behind Schedule Vehicle Occupancy
Its “budget” for priority
Traffic Signal Knows…. Where it is in its
timings Desired Time for
Service of Vehicle Relative “priority” of
all requests
Priority Request GeneratorsPriority Request
ServerTraffic Signal
Controller
Future TSP Perspective
Estimated Time of Desired
Service Priority Strategy
Implementations Issues
MANAGING EXPECTATIONS!!
Managing Expectations:Bus Operations
One Bus, One Route, One Trip
Multiple Buses, Multiple Routes, Multiple Trips
TRAFFIC MANAGER TRANSIT MANAGER
Managing Expectations:Scheduling
With TSP, I can better achieve
schedule!
With TSP, I can set new
aggressive schedule!
If the schedule was good in the first place, why
would I need TSP?
Managing Expectations:Responsiveness
Time Savings
To Transit
TransitFriendlyPhase
Priority Request Received
Expectation
TransitFriendlyPhase
Priority Request Serviced
TimeSavings
To Transit
OtherPhases
Reality
Managing Expectations:Time Savings
60 sec + 60 sec + 60 sec + 60 sec + 60 sec = 5 min
Expectations
10 sec + 50 sec + 0 sec + 25 sec + 30 sec = 1 min 55 sec
Reality
Managing Expectations:Coverage
Transit priority may NOT be appropriate everywhere! Tightly-timed intersections high volume, heavy
congestion Low volume intersections greater flexibility
Balance between traffic and bus operations
Future of Signal Priority
NTCIP Traffic Signal Control Working Group Tom Urbanik – Chair
Developing standards for signal priority control Rail, Emergency Vehicles, Transit,
Trucks Transit first
Completed in Summer 2002
Questions