Russell Pildes Department of Geography and GIS, College of LAS, University of Illinois at Urbana-Champaign

Connectivity and Accessibility of UIUC Campus Bike Paths

Acknowledgments

Dr. Sara McLafferty, GGIS

Dr. E. Heath Robinson, GGIS

Andrew Kopp, UIUC Facilities & Services

Conclusions • UIUC Campus is very well connected.

• Connectivity improves greatly

• Accessibility also improves but with notable

exceptions

• Study does not account for “rideability” or the ride

quality of bicycle paths

• Simple quantitative measures absent yet

demonstrably useful addition to transport studies

• Bicycles under-represented in literature

• Research is needed on rideability

• Philosophical and practical questions about

what makes a good bicycle network not truly

asked nor answered by transport planners

Research Goals

This project sought to answer three questions

using spatial statistics and novel GIS methods:

1. What is the current accessibility and

connectivity of UIUC campus bicycle

pathways?

2. What will be the accessibility and connectivity

of the planned campus bicycle pathways?

3. What would be the accessibility and

connectivity of the UIUC campus absent a

dedicated bicycle network?

All in pursuit of a bigger question:

What makes a “good” bicycle network?

Introduction

UIUC is home to a large and thriving bicycling

community. Following national trends, ridership on

campus is increasing. Combined with broader societal

pressure for responsible energy use and increased

daily physical activity, city planners and public health

officials have begun to focus on promoting “active

transport” methods for moving from place to place

within the built environment. However, bicycles and

“bikeability” have largely gone unstudied. No

studies including the 2013 Draft Campus Bike Plan

have applied quantitative measures of accessibility

and connectivity to bicycle networks.

This study examined the application of such methods

to begin to fill this void in planning literature by

examining the geometric connectivity and

accessibility of the UIUC campus bicycle network.

Methodology

• Connectivity is the measure of how linked different

locations or nodes are to each other on a network;

accessibility is the ease with which one can travel

between nodes.

• Calculate distance matrices using ESRI ArcMap

• Three indices of connectivity:

• Link-node-ratio (values 0-2.5)

𝐿𝑁𝑅 =𝑙

𝑛

• Alpha: % connectivity based on circuits (0-1)

𝛼 = 𝑙 − 𝑛 + 1

2 𝑛 − 5

• Gamma: % connectivity based on theoretical

max number of links (0-1)

𝛾 = 𝑙

3 𝑛 − 2

• One index of accessibility:

• Simple Accessibility: row-sums of distance

matrix (distance in miles)

Existing

Pathways

Planned

Pathways Streets

Nodes, Edges 61 80 76 122 159 279

Link-Node Ratio 1.31 1.61* 1.75*

Alpha 0.17 0.32 0.39

Gamma 0.45 0.55 0.59

Results

Connectivity

• Existing Pathways:

• LNR of 1.31 is excellent; Planned LNR

exceeds Ewing’s threshold of 1.4

• Alpha index: 17% of nodes are on a circuit

• Gamma index of 45% is very high

• Planned Pathways:

• LNR of 1.61 exceeds Ewing’s ideal planning

threshold of 1.4

• Alpha index nearly doubles; 32% chance

users can travel straight to next destination.

• Gamma index of 55% gives users 10% more

potential route options

• For all practical purposes, the Planned network

provides symmetrical service compared to the

control Street network.

Accessibility

• Accessibility improves greatly for some locations,

but not for all: FAR/PAR and Union disappear from

network, making it difficult to compare results.

• Planned network accessibility index is greater than

Existing, but actual accessibility is comparatively

lower.

Figure 2: Street network in the study area. Streets are grid systems by

design, making them ideal to transport people. Bicycle networks should

strive to provide symmetrical service to the streets, thus insulating cyclists

from motorist hazards.

Figure 1: Existing and Planned UIUC bicycle networks. The

Planned network improves overall connectivity and accessibility

over the Existing, but the Union and FAR/PAR become

disconnected; doors of all other marked locations are accessible by

bike path. Note: paths are slightly offset for visual assistance.

Planned

Accessibility Index

(miles)

Existing Index

(miles)

3.80 Illinois Street

Residence Hall 5.12

2.59 Undergraduate

Library 3.74

4.56 Grainger Library 6.12

Illini Union 4.47

2.88* Average Accessibility 5.29