Chapter12 Flashcards
Route Planning
dynamic process that involvesconstant reexamination of the details of route location, stop location, androute schedules.
· Publicpressure· Constructionof new traffic generators· Changesto transportation systemChanges in publicpolicies
Changes to bus service may also occur at irregular intervals due to
Route Location
decisions about the overall configuration of the transit network, thespacing of routes, and their detailed locations
· Radial–concentric· Grid· Multicentered
CLASSIFICATIONOF TRANSIT SYSTEM CONFIGURATION
- Concentrations of transitusers 2. Suitability of the streetsinvolved for bus traffic
Detailed route location is based on a number of considerations
· Reviewof street plans· Investigationof traffic conditionsField studies
Evaluation Process
· includehorizontal curve radii, street widths, intersection geometry, and grades.
Geometric Conditions
usually involve theadequacy of pavements but may also include load limits for bridges or otherstructures
Structural Concerns
include trafficcongestion, other adverse conditions, and provision of bus preference measures
Trafficcontrol–related issues
Signal overrides
are accomplished byspecial radio or photoelectric devices that enable buses to preempt the greenat traffic signals
Special lanes
are sometimesprovided by dedicating the curb lane for an extended distance
Signal overrides \n\nSpecial lanes \n\n TransitStreets or Transit Malls
Bus PreferenceMeasures
- Thenumber of stops actually made is not identical with the number of designatedstop locations.2. Thenumber of stops made does tend to increase as the number of stop locationsincreases.
Stop LocationPrinciples
Stop Spacing.
It is based on tradeoffbetween walking distances for passengers and the increase in bus travel timethat occurs each time the bus is stopped.
Clearance time.
It is the time spend in deceleratingand accelerating the vehicle and in opening and closing the doors.
Dwell time.
It is the time spend loadingand unloading passengers.
- Decisionsmust be made as to the relationship of the stop to intersections in thevicinity 2. Provisionof access to user concentrations 3. Safety 4. Conveniencefor transferring passengers
Considerationsin determining stop locations
a. Bus berths.
These are designated areasfor buses to pull over and load and unload passengers in major transitfacilities such as a transit center or park–and–ride facility.
- Sizeof a single berth 2. Numberof berths required
Issues involvedin designing a bus stop
Route Schedules.
Also knows as timetables, give the timethat successive buses pass points. They are most commonly constructed by maintainingapproximately uniform headways among successive vehicles during periods of time.
schedule blocks
periodsof time
time points
points
Headways.
They are influenced by the demand for service,with the shortest headway being maintained during busiest periods
CapacityHeadways. \n\nPolicyHeadways \n\nTotalCost Minimum Headways
Classification ofheadways
CapacityHeadways.
Headways such that the vehicles are just filledat the maximum load point on the route
Policy Headways.
Headways that are intended to representthe minimum acceptable standard for frequency of service.
Total Cost Minimum Headways.
Headways that minimize the sum of theoperating costs and the value of time spent by passengers waiting for service
Blocking
Process of determiningvehicle schedules.
Runcutting
The process of determininglabor schedules
Deadheading
Movement ofvehicles that are not in revenue service
Piece of Work
Consist of a combination of route andtime period to which a driver can be assigned
Straight Shift \n\nSplit Shift
Types of shifts
Trippers
Extra board drivers having irregulartrips that are not included in the schedule
Shakeup
Reconstruction of runs
Runs
Combined pieces of work
Guarantee
Payment with total work hours of lessthan 8 hours
Spread
Total time from the beginning to end of workday
· Emergencies· Routinemistakes· Coordinationof transfersSchedule instability
Major needs for real–time control:
· Ensuringthat vehicles are dispatched at the beginning of the day· Assigningextra board drivers to runs whose regular drivers fail to report· Dispatchingtrippers· Orderingschedule deviations
Responsibilitiesof Dispatchers
· Makingsure that drivers do not run ahead of schedule· Dealingwith equipment failures and other emergencies on the field
Responsibilities of Field Inspectors
· Automatictrain detection· Automaticspeed control· Automaticdispatching· Automaticberthing and door control at stations
Train controls by means of automatic system
· Transfercoordination· Preventionof vehicle bunching
Major issues in the real–time control of bus systems
· Totalridership for the route· Averagedemand past the maximum point· Overloading· Revenuecollected on the route· Estimatedcost of operating the route· Farebox recovery ratio· On–timeperformance· Publicinput
Common Performance Indicators includes:
· Rerouting· Rescheduling· SpecialMarketing Efforts· ModifiedDispatching PoliciesElimination ofService
Where deficiencies are noted, corrective action will be done like
