Sidewalk Planning: A GIS-Based Approach
Source: Pedestrian and Bicycle Information Center (PBIC)
Walking is our most basic form of transportation. Pedestrian travel is involved in every trip and is the basis for all other transportation modes. Pedestrian planning is vital for accessibility, health and well-being, social equity, and economic development. Prioritizing sidewalk projects and funding allocations can be a challenge for cities trying to proactively provide a pedestrian-friendly environment.
The Austin, Texas Public Works Department needed a process to prioritize sidewalk projects for sidewalk construction programs and funding allocation. In the past, Austin's approach to prioritizing project locations was based on input from neighborhood associations, special interest groups and business owners, along with anecdotal information from maintenance crews. The public works staff recognized that the city would be better served by developing a process based on objective data about each location's proximity to pedestrian attractors and risks. Austin also needed a process that took into account both the existing condition of the infrastructure and its compliance with the Americans with Disabilities Act (ADA) accessibility standards. The firm Lockwood, Andrews and Newnam (LAN) was selected to work with the city to identify priority pedestrian corridors, conduct field work to assess the condition and accessibility compliance status of sidewalks and curb ramps, develop the selection matrix, and use Geographic Information Systems (GIS) software to manage and implement the project.
LAN developed a Pedestrian Infrastructure Management System (PIMS) as part of Austin's Pedestrian Master Plan. PIMS is a custom GIS-based toolset which allows city staff to accurately identify potential sidewalk construction and maintenance projects, score and prioritize these projects using weighted comparisons, and provide cost estimates.
For the project, LAN performed a field assessment of the city's existing infrastructure for compliance with the ADA criteria for accessibility, identified maintenance issues, developed a GIS geodatabase to store infrastructure data, developed GIS tools to allow non-GIS users access to the data, designed a scoring matrix for project selection, and developed a map viewer utilizing ArcIMS (a Web map server).
The field assessment of the existing infrastructure used Global Positioning System (GPS) equipment to identify non-compliant locations to sub-meter accuracy. A custom ArcPad application was developed to simplify and streamline data collection in the field.
LAN designed and populated a geodatabase of pedestrian infrastructure features inventoried from orthographic imagery and data collected in the field assessment. This database includes absent and existing sidewalks, driveways, ramps and crosswalks for use in the prioritization of future projects. In addition, LAN developed databases and created datasets for use in the prioritization tool. Additional data were culled from several sources including the City of Austin, the U.S. Census, the Capital Area Council of Governments (CapCOG), and the Austin police department.
LAN developed a prioritization matrix to assist the city in identifying projects for future new construction and maintenance programs. Working with city staff, LAN determined that three criteria provide the best approach for prioritizing locations: proximity analysis to pedestrian attractors and risks, existing maintenance condition, and accessibility compliance of the existing infrastructure. Once a location is assessed on these three criteria, a cumulative score for that location is determined on weighted values assigned to each factor. The matrix was developed with extensive public input. LAN presented to neighborhood associations, city commissions and boards, and local committees with vested interest in pedestrian improvements. This prioritization matrix, along with the GIS-based toolset, results in improved efficiency for city staff when they plan sidewalk projects or respond to citizen requests and inquiries.
Using ArcIMS, LAN developed an interactive mapping application for use by the general public. This viewer allows users to identify their preferred pedestrian route prior to leaving their location. Viewers are able to identify locations of sidewalks versus absent sidewalks. In addition, users have the ability to identify maintenance and ADA issues along their route and make an informed decision about their pedestrian route.
The ultimate goal is to encourage walking as a viable mode of transportation, and improve safety, accessibility and pedestrian mobility in Austin. As a result of this project, LAN and the city have a detailed knowledge of Austin's sidewalk inventory, current condition of sidewalk assets, public perception of sidewalk needs and issues, and city sidewalk priorities. This tool facilitates the city's development of programs for new sidewalks, existing sidewalk maintenance, and accessibility improvements.
The cost of the GIS-based approach to sidewalk prioritization and planning is scalable. Factors affecting the cost include the scope of the project, the availability of existing datasets, the public involvement process, the sophistication of the customized tool, and many other factors influenced by the municipality's preferences.
Austin, Texas Pedestrian Master Plan (this page includes the city's proposed Sidewalk Prioritization Matrix): http://www.ci.austin.tx.us/edims/document.cfm?id=126322
Julie D. Hastings, PE
Lockwood, Andrews & Newnam, Inc.
10801 North MoPac Expressway
Building 1, Suite 120
Austin, TX 78759