Introduction: What is Transit Scheduling?

  • Transit scheduling is difficult because it requires the scheduler to have knowledge of both internal (transit operations) and external factors (agency policies and CBA)
  • The effectiveness of the transit schedule is heavily influenced by the agency’s service standards and policies
  • Even a small change in passenger demand, service policy, or traffic condition may necessitate producing a new schedule
  • The most common issue of transit scheduling is vehicle and driver assignment due to some constraints presented by labor union agreements

Scheduling Process

Timetable Development

  • In this step, the scheduler develops a service schedule for a particular route
  • The scheduler assembles information to develop a timetable, including:
    • Span of service
    • Headway
    • Timepoints
    • Running times
    • Round-trip cycle time
    • Layover/recovery time
  • The use of reliable information is critical in this step, as it affects the quality of service

Blocking (Vehicle Assignment)

  • Blocking: Assigning trips to specific vehicles
  • The scheduler determines the number of vehicles needed to operate all trips in the timetable
  • Once the timetable is created, the scheduler starts to link trips together to create work assignments that later must be assigned to vehicles
  • Schedulers use blocking sheets as a tool to manually enter the detailed information, including:
    • Block number
    • Pull-in times
    • Trip numbers
    • Departure and arrival times at terminal points
    • Pull-out times
  • Crucial process due to affecting operating costs

Run-Cutting (Driver Assignment)

  • Assigning the blocks to different operators (drivers)
  • The scheduler breaks up the blocks into individual drive rassignment/work pieces (runs)

Rostering (Crew Assignment)

  • Rostering: Grouping runs into weekly work assignments
  • Transit agencies use either
    • Operator-developed (cafeteria style) rostering
    • Agency-developed rostering
  • Drivers must select their work assignments for the next time interval during the bid process

Major Functions of the Transit Scheduler

Adhering to Applicable Rules, Standards, and Policies

  • Schedulers must have an understanding of the transit agency, structures, policies, objectives and other related issues
  • CBAs or union contracts contain particular requirements that impact the scheduling process in terms of how the service is scheduled, blocked, and cut into driver runs

Developing Schedule Scenarios for Planning Purposes

  • Although service planners plan routes that meet the required criteria, schedulers make the route work operationally

Building Reliable Schedules

  • Customer service is directly affected by the reliability of transit schedules
  • Schedules provide essential information to riders, including:
    • Departure times
    • Arrival times
    • Trip duration times

Providing Good Working Conditions in Operators Assignments

  • Schedulers should prepare route schedules and operators’ assignments in a manner that provides good working conditions for drivers
  • Since transit schedules include operators’ workday assignments, providing a good schedule can minimize operators’ level of stress and absenteeism
  • Since operators directly interact with customers, running and layover times may affect this interaction

Supporting Other Organizational Sections

  • Scheduling provides information and data to support other sectors, including:
    • Administration
    • Marketing
    • Planning
    • Operations

Estimating Service Costs and Requirements

  • Scheduling information is needed to estimate operating costs, vehicle requirements, and operator staffing needs for proposed service changes
  • Operating costs are the major expenses transit agencies deal with
  • The scheduler’s responsibility is to be aware of operating resources and minimize costs in such a way that it doesn’t affect reliability in terms of:
    • Require service frequency
    • Operating speed
    • Safety

Timetable Development

What is a Timetable?

  • Generating a schedule for services operated by public transit vehicles
  • A schedule showing the arrival and departure time of buses from specific locations, called timepoints

Service Standards and Policies

  • An agency’s standards and policies place some restrictions on the scheduling process
    • Which sections of timetable development are mostly affected by service standards and policies?
  • Organizational guidelines and policies greatly affect:
    • Route patterns
    • Service frequencies
    • Service timing

Route Patterns

  • Route: Way/path a transit system selects for operating its service
  • Routes often maintain a main path called the trunk, which may be further divided into branches
  • Route variation occurs when the scheduled service operates on a path that deviates from the trunk
  • 3 typical route patterns:
    • Loops
    • Short turns
    • Branches

Loops

  • An alignment/path shaped similar to that produced by a loop that bends around and crosses itself

Short Turns

  • Service ends at an intermediate point of the route and the route turns before arriving to the end of a route
  • Used in scheduled trips when the vehicle doesn’t need to go along the full route
  • Adds passenger capacity to a part of the route
  • Can reduce operating costs when there’s lower demand for service along the part of the route not served by short-turning trips

Branches

  • Outer route segments that serve a number of trips
  • Multi-branch routes have “trunks” that serve the majority of trips
  • Service headway in a trunk may differ from branches as trunks usually have more frequent service

Running Time

  • Scheduled time (in minutes) assigned to a revenue vehicle to move along a route, from one timepoint to the next
  • Running time includes driving time and dwell time
  • Schedulers determine expected running times by:
    • Retrieving actual running time data
    • Considering the route traffic conditions
    • Using their historical experience

Layover and Recovery Time

  • Out-of-service/break time, which is allocated to operators somewhere along the route
  • Recovery/layover time allows bus operators to catch up to the schedule when running late
  • A type of time allowance, mainly use to maintain schedules
  • Labor agreements and agency policies usually determine the minimum layover and recovery time required for a round trip
    • Ex: 10% layover/recovery time in a 76 minute round trip leaves 8 minutes for layover/recovery time \((76 \cdot 10\% = 7.6 \approx 8 ~ \text{min})\)

Cycle Time

  • Cycle time is the sum of the running time and the layover/recovery time
  • Schedules maintain a constant headway/interval time between revenue service that move in the same direction
  • Running times may vary during different times of day due to traffic or other issues
  • Routes with multiple patterns will need cycle times determined for each pattern and time period

Terminal Points

  • The end of a line/route where vehicles begin and end their revenue services
  • Terminal points serve as both convenience and safe locations with:
    • Parking spaces
    • Restrooms
    • Restaurants
  • The number of terminal points depends on several factors but usually, as a route pattern becomes more complex, its number of terminal points increases

Intermediate Timepoints

  • Usually placed at similar distances along the route or at locations close to high activity centers such as:
    • Shopping centers
    • Hospitals
    • Schools
    • Government facilities
  • Schedulers try to set times at each timepoint with a high chance that the vehicle’s actual arrival/departure time matches the scheduled time
  • The bus needs to wait and depart at the actual time shown in the timetable if they arrive at a timepoint early

Internal Timepoints

  • Points that help operators adhere to the schedule
  • Not shown on public timetables but on operators’ schedules

Relief and Transfer Points

  • Relief points are locations where work shifts between operators change
  • Operator relief is often planned when the scheduled number of hours for a vehicle exceeds the number of hours an operator is scheduled to work in a day
  • Transfer points are locations where transit routes intersect

Trip Shifting

  • It may be necessary to shift one or more trips forward/backward in time
  • For lack of a proper place for:
    • Layover
    • Adjusting schedule times
    • Meeting circumstances like school bell time

Transitioning

  • Implementing changes in running time, headway, or both in a gradual matter
  • Ex: Headway in one route may be 15 mins during peak hours and 30 mins during base hours
    • Smoothing out the headway change from 15 mins to 30 mins allows service to gradually change into the new desirable pattern

Master Schedule

  • A document that contains all detailed trip information by direction
  • Inclusion of all individual trips on a route

Running Time

  • Times are often different due to various reasons including:
    • Traffic congestion
    • Route configuration
    • Boarding levels
  • The existence of a loop at the end of a route may cause a running time difference

Headway

  • The time difference between two consecutive vehicles operating in the same direction on the same route
  • Since passenger demand is higher during peak hours, headways are frequently smaller and vice versa
  • Depends on passenger load and capacity of the vehicle

Round-Trip Cycle Time

  • Cycle time is the sum of the round-trip running time and layover/recovery time
    • Round-trip running time calculation: \((52 + 52) = 104\)
    • Minimum layover/recovery time: Assuming 10%, \(104 \cdot 10\% = 10.4 \simeq 11 ~ \text{min}\)
    • Add the 11 minutes to the round-trip running time of 104 minutes for the minimum cycle time of 115 minutes

Available Cycle Time

  • Can’t operate the 60 minute headway as the cycle time must always be a multiple of the headway
  • Calculating the number of vehicles requires dividing cycle time by headway (\(\dfrac{115}{60} = 1.92\))
  • Because you can’t operate 1.92 vehicles, we round up to 2 vehicles for a 120-minute cycle time

Applicable Layover/Recovery Time

  • In the 120-minute cycle time, we shift from 11 to 16 minute layover/recovery time \((120 - 104 = 16)\)