Business Logistics 420 Public Transportation

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Business Logistics 420Public Transportation

• Lecture 20 Transit System Design

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Lecture Objectives

• To understand the basic elements of transit
  system design
• To appreciate the different transit system route
  configurations
• To know the basic principles of good route design
• To understand other aspects of system design such
  as schedules, stop location

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Elements of Transit System Design

• Overall system -- route interrelationship
• Individual route design
• Scheduling
• Stop locations
• Vehicle Selection

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System Considerations

• Service area definition
• Location of major generators
• Route pattern -- network
• Radial -- circumferential
• Grid -- rectangular
• Combination
• Irregular
• Route spacing
• Transfers -- inter and intra modal
• Marketing considerations

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Chicago Loop -- Grid Network
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Washington Metro -- Radial
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CATA -- Radial System
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ATA -- Bradford, Pa -- Irregular
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Route Design Guidelines

• Use direct routing where possible
• Through routing is preferred to cycle routing
• Reverse or loop routing should be used sparingly
• Routes should begin and end at major generators

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Route Design Guidelines (Continued)

• Routes should be spaced about 1/2 mile apart
• Routes should provide direct service -- circuity
  ratio (actual route miles/direct auto travel)
  should not exceed 1.33
• Initial route design assumes average speed of 12
  miles per hour

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CATA - P Route -- Through Routing
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CATA C Route -- Poor Circuity
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CATA -- CS Route --Reverse or Loop Routing
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Factors Influencing Route Design

• Demand
• spatial arrangement
• special generators
• Urban environment
• street network (one-way streets)
• congestion
• Management Considerations
• driver scheduling
• labor rules

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Factors Influencing Route Design (Continued)

• Intermodal Coordination
• Rail/bus/paratransit
• Intercity facilities (rail, bus, air)
• Political Considerations
• Equity
• Pressure

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Scheduling Considerations

• Two major issues
• Headway time between vehicles Ex 15
  minuteheadway represents four buses per hour
• Timing of arrivals at points along the route
• Factors to consider
• quality of service (frequency)
• transfers
• easy memorization
• driver labor requirements

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Scheduling Considerations (Continued)

• Setting headways
• Maximum headway (fewest minutes between vehicles)
  set based on capacity needed to meet demand
• Minimum headway based on policy decisions, e.g.,
  all routes should have no less frequent service
  than 30 minutes in the peak and 60 minutes off
  peak

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Scheduling Considerations (Continued)

• Setting arrival times
• Independent scheduling
• Most common approach
• OK if short headways, but may cause transfer
  problems if long headways
• Pulse scheduling timed transfers
• Attractive approach for systems with long
  headways
• Improves service quality
• Hard to implement due to space constraints at
  stops and variability of travel times

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Stop Locations

• Operations
• location (Near side, far side, mid block)
• peak number of buses at stop at any given time
• Quality of service
• near destinations
• spaced 750 ft or more apart to maintain operating
  speed
• adequate waiting area -- shelter

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Stop Locations (Continued)

• The urban environment
• parking restrictions
• turns
• Special concerns in Edge City, big box
  environment
• bus stop near store entrances rather than across
  sea of parking
• circuity concerns if store too far from road

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Vehicle Selection

• Size of vehicle
• Peak loads (goal to provide 5 sq ft/psgr so 8 x
  40 ft bus 320 sq ft or 64 passengers max.
• Traffic conditions
• street width
• turning radius
• Number of vehicles
• Peak hour requirement plus 10 spares

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Miscellaneous System Design Issues

• Special service types
• freeway flyers
• skip stop operation
• local vs express
• New service types
• service routes (fixed-route with deviations)
• paratransit feeder services

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Study Questions

• What are the major aspects of transit system
  design?
• What are the basic types of transit route network
  configurations?
• What are the basic route design guidelines?
• What are good route designs? What are poor
  designs?
• What factors influence scheduling decisions?

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Study Questions (Continued)

• What factors are important when selecting vehicle
  size and numbers?
• Pick up a CATA Ride Guide in the HUB, Kern, or
  inside the doors to Willard (new building side
  on Pollock Rd.) to serve as reference for this
  lecture