Optimal Zone Design for Feeder Transit Services

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Optimal Zone Design for Feeder Transit Services

• Xiugang Li and Luca Quadrifoglio
• Zachry Department of Civil Engineering
• Texas AM University, College Station, TX
• Presented at the 12th National Transportation
  Planning Applications Conference
• May 21, 2009
• Houston, TX

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Outline

• Introduction
• Research Objective
• System Description
• Analytical Model
• Application

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Introduction

• Demand-Responsive Feeder Transit (DRC)
• Implemented in some cities, such as Denver
• Service area a demand-responsive operation
• Major transit network

4
Research Objective

• For large communities, planners may divide the
  whole service area into zones
• A non-optimal structure often adopted
• We developed a rigorous design methodology with
  analytical formulas

5
System Description

• Service area divided into n zones
• Within each zone, fixed-route transit (FRT) or
  demand-responsive transit (DRC) adopted
• A fraction ? of customers move from the service
  area to the terminal

Major
L
Transit
Network
Zone 1 Feeder line operations
Terminal 1
Terminal 2
W
Zone 2 Feeder line operations
Terminal 3
Zone 3 Feeder line operations
Point Z
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Analytical Model

• Total Cost Function
• FRT Total Cost Customer Cost FRT Bus Cost
• DRC Total Cost Customer Cost DRC Vehicle Cost
• Customer Cost waiting, walking, ride

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Analytical Model

• Optimal Number of Zones, n
• FRT Total Cost f(n) is a convex function
• DRC Total Cost p(n) is a convex function

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Application

• We applied the model to El Cenizo, Texas - one of
  the colonias, which are unincorporated
  settlements along the U.S. Mexico border
• With collected travel demand data, we determined
  optimal number of zones
• One-zone design is the best for FRT policy
• For DRC policy one-zone is best when demandlt50
  larger demand has more than one zone, but cost is
  larger than FRT policy so choose one zone

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More detail in Xiugang Li and Luca
Quadrifoglio, Optimal Zone Design for Feeder
Transit Services. TRB 88th Annual Meeting
Compendium of Papers DVD (Paper 09-2608), or
Transportation Research Record (in Press) Thank
You Very Much