Development of a Transit Model Incorporating the Effects of

Accessibility and Connectivity

9th Conference on the Application of Transportation Planning Methods

Baton Rouge, LouisianaApril 6-10, 2003

Research Team Ram M. Pendyala

Dept of Civil & Environmental Engineering, Univ of South Florida, Tampa

Steve Polzin & Xuehao ChuCenter for Urban Trans Research (CUTR), Univ of South Florida, Tampa

Seongsoon YunGannett Fleming, Inc., Tampa

Fadi NassarKeith & Schnars PA, Fort Lauderdale

Project Manager: Ike UbakaPublic Transit Office, Florida Dept of Transportation, Tallahassee

Programming Services: Gannett Fleming, Inc.

Outline

Background History of transit model development in Florida BEST 3.0: Third generation transit model

system Role of accessibility and connectivity BEST 3.0 methodology Accessibility/connectivity methodology Model development

Data Estimation Application

Background

Transit systems planning and analysis Accessibility Availability Quality of Service Ridership Temporal Characteristics Transfers Route/Network Design Fare Policies and Structure Alternative Modal Options/Technologies/Route

Types Disaggregate Stop-Level Analysis

History of Transit Model Development FDOT Public Transit Office very proactive in

transit planning tool development TLOS, FTIS, and INTDAS examples of transit

planning and information tools Transit ridership modeling tools

ITSUP: Integrated Transit Demand & Supply Model RTFAST: Regional Transit Feasibility Analysis &

Simulation Tool Powerful stop-level ridership forecasting

models

Stop-Level Ridership Forecasting First generation ITSUP sensitive to

demographic variables and frequency and fare of service

Second generation RTFAST accounted also for network connectivity (destination possibilities)

Desire transit ridership forecasting model that accurately accounts for accessibility/connectivity

Third generation model called BEST 3.0 Boardings Estimation and Simulation Tool

BEST 3.0 Model estimates number of boardings at stop

by: Route Direction Time period

Model estimates two types of boardings: Direct Boardings: Walk and Bike Access Transfer Boardings: Transit Access

Separating Direct and Transfer Boardings Consider two types of stops, i.e., stops with

no transfer possibility and transfer stops Estimate direct boardings model using data

from non-transfer stops Apply direct boardings model to transfer

stops to estimate direct boardings at transfer stops

Subtract estimated direct boardings from total boardings to estimate transfer boardings

Then estimate transfer boardings model

Role of Accessibility and Connectivity Transit ridership strongly affected b y:

Destination accessibility Temporal availability Network connectivity

Desire to have BEST 3.0 sensitive to all three aspects of transit accessibility

Ability to test effects of alternative route and network design configurations on transit boardings

Sophisticated methodology incorporated into BEST 3.0

BEST 3.0 Methodology

NnXOOOOBRfD sn

sn

sn

sn

sn

ssn

sn ,...,1,,,,,,, 5432 s refers to stop on a route in a given direction and

n refers to time period D = direct boardings R = number of bus runs B = vector of buffer characteristics Oi = vector of accessibility to characteristics of

buffer areas for Hi stops, i = 2, 3, 4, 5 X = vector of other route and stop characteristics

BEST 3.0 Methodology

T = transfer boardingsO1 = vector of accessibility of boarding at H1

stops during period n toward stop s Y = vector of other route and stop characteristics

Methodology thus includes both direct and transfer boardings equations

Accessibility vectors play major role

NnYOOOOORgT sn

sn

sn

sn

sn

sn

sn

sn ,...,1,,,,,, 5,4321

Definition of Stops Stops are defined with three pieces of

information: Physical location Route Direction

Example 1: 2 routes intersect

Example 2: 4 routes serve one location in the same direction

141

4

141

4

Neighboring Stops N1 = Neighboring stops along the same route N2 = Stops along the same route but in the

opposite direction that lead to different destinations providing the same opportunities.

N3 = Neighboring stops along other routes that lead to different destinations providing access to opportunities for the same activities.

N4 = Neighboring stops along other routes that lead to the same destinations. These routes may or may not share the same roads with the particular route in question

Neighboring Stops (N1) N1 = Neighboring stops along the same route

Stop inQuestion

Neighboring Stops (N2) N2 = Stops along the same route but in the

opposite direction that lead to different destinations providing the same opportunities

Stop inQuestion

Neighboring Stops (N3) N3 = Neighboring stops along other routes

that lead to different destinations providing access to opportunities for the same activities

1414

141

4

Stop inQuestion

14

Neighboring Stops (N4) N4 = Neighboring stops along other routes that lead to the

same destinations; these routes may or may not share the same roads with the particular route in question

Stop inQuestion

Competing Routes/Stops

Notion of neighboring stops effectively captures effects of competing routes/stops

Riders may choose alternative stops, routes, destinations for pursuing activities

Need to identify and define upstream and downstream stops that can be reached using neighboring stops

Define series of stops, H1 through H5, identified by network connectivity

Accessible Stops: Illustration Network

2

10

14

11

15

12

16

1

5

9

13

43

876

Route 1

Route 2

Route 3

Route 4

Route 5 Route 6 Route 7 Route 8

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14

14

Neighboring Stops: Illustration Network

Network8 routes (each two way)16 nodes (n=1, …, 16)64 stops (nX, n=1,…, 16; X=N,S,E,W)

Neighboring StopsN1 = {2S}N2 = {6N}N3 = {6W, 6E}N4 = {6W, 6E}

Accessible Stops: Illustration Network H1 = {1S, 1E, 2E, 2W, 3E, 3W, 3S, 4W, 4S, 5E, 7W, 8W, 9N,

9E, 10W, 10E, 11W, 11E, 12N, 12W, 13N, 13E, 14W, 14E, 15W, 15E, 16W, 16N}

H2 = {1W, 2N, 3E, 4E, 5S, 7S, 8S, 9S, 11S, 12S, 13S, 15S, 16S}

H3 = {1N, 3N, 4N, 5N, 7N, 8N, 9W, 9N, 10S, 11E, 11N, 12E, 12N, 13S, 13W, 14S, 15E, 15S, 16E, 16S}

H4 = {1N, 1W, 2E, 2W, 3N, 3E, 3W, 4E, 4N, 5W, 5N, 7E, 8E, 9S, 10E, 10W, 11E, 11W, 12S, 12E, 13S, 13W, 14E, 14W, 15E, 15S, 15W, 16S, 16E}

H5 = {1N, 1W, 3N, 3E, 3W, 4E, 4N, 5W, 5N, 7E, 8E, 9S, 10E, 10W, 11E, 11W, 12S, 12E, 13S, 13W, 14E, 14W, 15E, 15S, 15W, 16S, 16E}

Defining Accessible Stops H1 includes stops that can reach the N3 and N4 neighboring stops

(Interest: boardings) H2 includes upstream stops that can be reached from the N2 stops

(Interest: buffer area) H3 includes stops downstream that can be reached from stop in question

through route serving the stop in question via the transit network (Interest: buffer area)

H4 includes stops that can be reached from the N3 and N4 neighboring stops (Interest: buffer area)

H5 includes stops in H4 that overlap with stops in H3 (Interest: overlapped area)

Computing Transit Accessibility

Two components of transit accessibility Access/egress at stop in question Accessibility from stop to all other stops in network

Access/egress at stop in question measured through simple air-distance buffer distance

Accessibility from one stop to all other stops in network uses gravity-type measure:

ji

ji

ji

s

sn

ssjn GQO

Computing Transit Accessibility Oi is the measure(s) of accessibility included in the boarding

equations Q represents buffer characteristics of stops in H2 through H5

and boardings at stops in H1

G represents impedance from stops in H1 and impedance to stops in H2 through H5

is gravity model parameter Impedance measured by generalized cost of traveling from

one stop to another

Computing Impedance, G Components of impedance

First wait time First boarding fare In-vehicle time Transfer wait time Number of transfers Transfer walking time Transfer fare

Model sensitive to host of service characteristics

Components Unit Value/SourceSymbo

l

Weight

Symbol

Value

First-wait time

MinutesHalf of first headway with a cap of 30

FWT WFWT 3.0

First-boarding fare

Dollars Base cash fare FBF WFBF 1/v

In-vehicle-time

MinutesCumulative scheduled travel time

IVL WIVL 1.0

Transfer-wait time

MinutesHeadway of transfer stop if no coordination and deviation if coordinated for up to two transfers

TWT WTWT 3.0

Number of transfers Number Up to two NTF WNTF 5.0

Transfer-walking time

Minutes

Time to transfer stops at 3 mph

TWK WTWK 1.5

Transfer-boarding fare

Dollars Base cash fare for transfers TBF WTBF 1/v

v = half of average hourly wage rate in service area

Components of Impedance, G

Model FunctionalityBEST 3.0 will retain user functionality from first

two generationsGIS interface for database setup and displaysSets of default equations by time periodAutomated bufferingAutomated accessibility and impedance computationsReport generation including performance measures

Model DevelopmentBEST 3.0 software development underwayModel estimation using APC data from Jacksonville,

FloridaUsing Census 2000 data for socio-economic variablesProgramming accessibility and impedance

computation capability at this timeAnticipated release of software in late summer or

early fall

Conclusions BEST 3.0 will provide a powerful framework for modeling

transit ridership at stop level Incorporates effects of accessibility and connectivity on

ridership Accessibility and impedance computations very

sophisticated and accurate More precisely accommodates effects of service span

and frequency (temporal aspects) Focus on ease of use and quick response capability