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Transportation Planning and Sustainability Guidebook

Chapter 4: Data Collection & Availability for Sustainability Assessment

Section I. Introduction

Sustainability planning, assessment, and monitoring relies on data from a variety of sources to provide a complete picture of the environmental, economic, and social impacts as well as the basic functionality of transportation projects or agencies themselves. In the United States and internationally, data quality and availability have proven to be significant barriers to comprehensive transportation sustainability assessment (31,58,59). A research team in the UK developed an indicator-led approach to appraising sustainability in transportation. The appraisal method examines relationships among transportation, economy, environment, and society to cover all of the objectives in the UK sustainable development strategy and the European Commission's accepted definition of sustainable transportation. The goal was to operationalize already accepted definitions by selecting appropriate indicators. The research team intended to select indicators that were already in use or that relied on an existing data source in order to help with tracking progress from an established baseline. However, they found that several proposed indicators lacked data sources; in particular, the key social sustainability indicators like out-of-pocket transportation costs, quality and security of local environment for walking and cycling, equity of access to transport network from affordable housing (58).

For certain purposes, like developing performance measures or indicators for project delivery or system conditions, transportation agencies may face a data overload -- there may be too much data to choose from and the agency may struggle with what is the most important or most meaningful data to track. However, when it comes to sustainability assessment (particularly economic and social equity/quality of life impacts) agencies face a lack of sufficient data or may have questions about which measures are meaningful indicators of progress. In responding to survey questions about performance measures, DOTs demonstrated that they collect numerous environmental indicators (some of which are required by law) but fewer economic and social indicators. One DOT in particular expressed difficulty in finding a direct measure for social sustainability. Arizona, Delaware and California DOTs have been working to find appropriate performance measures. They reported difficulty in narrowing the list of measures to a manageable number and selecting the most meaningful ones. Further, data collection is costly and requires significant use of resources, and transportation agencies may find it difficult to prioritize additional data collection over other more urgent needs.

For sustainability, developing indicators may require creative use of available data. For example, several variables can be combined into a quality of life index. When considered alone, the data may indicate a certain state but when considered jointly the data may suggest trade-offs that occur. The UK's and other experiences (29, 59, 60) suggest that disaggregating traditional transportation statistics by transportation mode, geography or socioeconomic group could be a method for analyzing social equity. Such an analysis would require census data (demographics, geopolitical boundaries) and available transportation statistics.

Organizing indicators into a sustainability framework - like New Zealand, Texas or Missouri - can help narrow down a list of indicators or identify additional data that needs to be collected. Indicators ought to be linked to specific agency goals and the overall agency vision. By linking indicators to specific agency goals, objectives, and targets, it becomes necessary to sort through all of the available data and only choose indicators that provide a meaningful measure. Rather than collecting and tracking every possible piece of data, only the most important are selected (which can be financially beneficial given limited resources). With a streamlined list of indicators, the transportation agency can then track performance and more easily pinpoint why targets are not met. The agency can also assess trade-offs among different indicators that may result from policies. This must be done with the understanding that performance measures need not be static but must accurately reflect what the agency is trying to accomplish, as what gets measured gets managed. By considering the key indicators for assessing sustainability, gaps in data availability can be identified to guide future data collection or interagency data sharing.

Considerable benefits can be achieved by improving the coordination of existing transportation statistics gathering activities. Data cost effectiveness could be improved significantly. Data quality and usefulness could also be improved by focusing on: comprehensiveness, consistency, frequency, accuracy, transparency, and availability (61). In the meantime, transportation agencies can strive to identify meaningful measures based on available data sources. Following New Zealand and the UK's lead, agencies can also identify measures that they would like to have and potential sources for the data.

Section II: Available Data Sources

A significant challenge for sustainability analysis, evident in DOT interviews and the literature, is finding the right data at the appropriate geographic scale, level of aggregation, or timeframe. In the United States there are several publicly available and commonly used data sources for transportation and socioeconomic data. Table 4-1 summarizes some of these datasets. Environmental data sources, that are used more widely because of NEPA, are not included here.

Table 4-1: Publicly Available Datasets for Transportation Analyses
Data SourceFrequencyDescriptionGeographic Scale
APTA Transit StatisticsAnnualAnnual statistics for US public transportation; Annual agency-specific statistics; historical time series statistics for USUnited States; Local providers
BTS State Transportation StatisticsAnnual*Compilation of transportation statistics from multiple sources (timeframes vary)State
DOE's Transportation Energy Data BookAnnual (from 1976)Transportation statistics on fuel consumption, emissions, etc. (http://cta.ornl.gov/data/index.shtml)National
Environmental Protection Agency's EnvirofactsPeriodic, variableClearinghouse of EPA data sourcesZip code, city, county, state
FHWA National Bridge Inventory (NBI)AnnualCondition of bridge infrastructureState (individual bridges)
FHWA National Household Travel SurveyVariable (1969-2001)Daily travel by all modes and traveler characteristicsNational
FHWA's Highway StatisticsAnnualInformation on US road conditions, highway travel, and expenditures State and City
Highway Performance Monitoring SystemPeriodic, variableNational level highway information systemStates
National Transit DatabasePeriodic, variableNational database of statistics for the Transit IndustryNation's Transit Agencies
Texas Transportation InstitutePeriodic, variableUrban Mobility ReportU.S. Metropolitan Areas
US Census American Community Survey (ACS)Annual (from 2005)Similar data to US Census long formAreas with population >65,000
US Census Bureau's Annual Economic SurveysAnnualLocal economic patterns by industry County and Zip Code
US Census Bureau's Decennial Census10 yearsDemographic dataNational, state
US Census Bureau's Economic Census5 yearsProfile of businesses and industryBy industry (or establishment)
US Census Bureau's Population EstimatesAnnualPopulation estimates for year's between decennial censuses by demographic groupNation, state, counties
US Census Transportation Planning Package10 yearsTravel data (will be based on ACS)Local, county, state

For purposes of long-range planning, these data sources are produced at an appropriate time interval. However, for sustainability performance monitoring and lower-level planning activities, this data may not be sufficient. For example, there is no single integrated multi-modal database at the federal level. Many MPOs or state DOTs supplement public data sources with regional travel surveys, local land use information (primarily from comprehensive planning or zoning regulations), and data collected in-house (traffic counts, safety statistics, etc.). Additional data may also be available from other relevant state agencies, like economic development and public health departments or environmental agencies.

Data for evaluating system performance is collected regularly by transportation agencies and includes pavement condition, travel times, crash rates, etc. Measuring system performance is a necessary piece of sustainable transportation assessment, but not sufficient on its own. If a transportation system improves its operations at the expense of the environment, economy, and/or society, it may not be sustainable. When taken together, these four areas represent the sustainability of the transportation system and/or agency.

Various DOTs have been collecting data on the environment for several years as a result of the 1969 NEPA and several subsequent laws regulating air quality, water quality, noise, historic preservation, etc. Today agencies are able to evaluate the impacts of projects on the environment, both natural and built, by tracking noise pollution, construction run-off, wetland replacement, material recycling, and other data collected in-house. Agencies also gather data on operational impacts, both internal (like DOT fleet fuel consumption, energy use, paper recycling) and external (like air quality and highway plantings). Now, with emphasis on climate change and energy independence, transportation agencies are beginning to measure greenhouse gas emissions and fuel consumption. While a considerable amount of environmental data is collected by the transportation agency, additional data is obtained from federal and state resource agencies or local governments.

When it comes to sustainability indicators for the economy or social equity/quality of life, agencies tend to lack sufficient data sources. Aside from estimates of project costs and benefits, a majority of economic data is obtained from outside agencies like the US Census Bureau, state or local economic development agencies, and private data collection companies. Developing social indicators can require creative use of available data. For example, several variables can be combined into a quality of life index; when considered alone the data may indicate one state but when considered jointly the data may suggest trade-offs that occur. The UK experience (29) suggests that disaggregating traditional transportation statistics by geography or socioeconomic group could be an effective method for analyzing social equity. Experience in the United States in applying Health Impact Assessment (HIA) to transportation projects also supports disaggregation of available data as a means for assessing social impacts (60). Such an analysis requires census data (demographics, geopolitical boundaries) and available transportation and health-related statistics. GIS could also aid in such an analysis.

Data sources for GIS are becoming increasingly necessary for early environmental screenings and for assessment of economic, social, and land use impacts. GIS analysis is recommended as an effective way to examine local impacts during a strategic sustainability assessment and is also a valuable visualization and analytical tool for spatial analysis and scenario planning. In interviews with state DOTs, several mentioned using GIS to help identify environmental impacts (Delaware, Tennessee, Florida) and others expressed a desire to do so but cited the availability of data files as a primary barrier. In order to fully utilize GIS analysis, statewide data sources for transportation infrastructure, land use, and environmental features would be necessary. There are numerous GIS data clearinghouses available online, but not all data sources are free, and some may not provide the detail necessary to conduct corridor or project analyses. Additionally, there may be data gaps in states or counties that do not generate their own GIS files. For specific transportation projects, GIS data can be generated by attaching spatial data to existing data sources like transit station locations or employment centers (essentially mapping either manually or with GPS equipment). Creating GIS datasets is often costly and labor-intensive.

The GeoCommunity Data Catalog and Geospatial One Stop (geodata.gov) are two examples of clearinghouses that offer statewide and county-level data. There are also specific GIS data sources with particular relevance to transportation planning. Examples include:

Additional GIS resources are provided on the FHWA website.

The data sources presented above are the most commonly used sets for transportation planning because of the frequency of collection, appropriateness of scale, and convenient format. Additional data sources are available but may not be as useful for transportation planning purposes due to limited scale, less frequent collection, and cost of use (see Table 4-2).

Table 4-2. Additional Transportation and Sustainability Data Sources
Data SourceFrequencyDescriptionGeographic Scale
Housing and Transportation Affordability IndexVariesMaps housing and transportation costs as percent of income, annual household gasoline expenditures, carbon dioxide emissions from household auto use, and custom comparisons (user selected variables) http://htaindex.cnt.org/Select US metropolitan regions
Metropolitan Travel Survey ArchivesVariesDatabase of travel surveys conducted by US states or metropolitan areas http://www.surveyarchive.org/archive.htmlState and Metro
National Highway Traffic Safety AdministrationVariesSafety data and statistics for US states and the nation as a whole http://www.nhtsa-tsis.net/State, National
North American Transport Statistics Online DatabaseAnnual (1996-2005)Transportation-related data in twelve thematic categories for the US, Canada, and Mexico http://nats.sct.gob.mx/sys/index.jsp?i=3Nation
TranStats: Intermodal Transportation DatabaseVariesSearchable index of US transportation datasets http://www.transtats.bts.gov/Varies
US Bureau of Labor Statistics' Consumer Expenditure SurveyAnnual (1984-2007)Statistics on consumer patterns http://www.bls.gov/cex/Nation
Cross-National Time-Series Data ArchiveAnnual (since 1815 for some countries)Variety of demographic, economic, transportation, education, and other data collected for over 200 countries (must pay for a license) http://www.databanksinternational.com/Nation
EarthTrends Searchable DatabaseVariesDatabase of over 600 variables relating to transportation, environmental systems, and energy use http://earthtrends.wri.org/miscell/sitemap.php?theme=0City, Region, Nation
iRAP International Transport Statistics DatabaseVariesVarious statistics for several countries, including the US http://www.iraptranstats.net/International (Nation)
IRF's World Road StatisticsAnnual (since 1964)Collection of national transport statistics for over 185 countries http://www.irfnet.org/statistics.phpNation
Millennium Cities and Mobility in Cities databases 2001Transportation data on over 100 world cities (pay for service) http://www.uitp.org/publications2/store/index2.cfm?id=5&#mcdInternational (City)
National Footprint AccountsVariesContains data sources for each ecological footprint including Food and Agriculture Organization of the UN, the International Energy Agency, the UN Statistics Division, and the Intergovernmental Panel on Climate Change http://www.footprintnetwork.org/en/index.php/GFN/page/methodology/International (Nation)
United Nations (UN) Global Urban Observatory DatabaseVariesTransportation, land use and other data for world cities http://ww2.unhabitat.org/programmes/guo/International (City, Nation)

Section III: Applications of Data Sources

This section demonstrates applications of different data sources in various sustainable transportation planning practices and assessment methods identified in the survey and literature. Table 4-3 summarizes various practices, data requirements, sources, and limitations. A similar analysis is provided as part of each case study in Chapter 5. In addition to the publicly available data sources in Tables 4-1 and 4-2, some of the practices require data from private sources, which may not be free or easy to obtain. Also, GIS-based practices depend upon the availability of a comprehensive database, and so may not be easily applied by all state DOTs. Development of GIS databases for the purpose of sustainability assessment requires cooperation among multiple agencies and can be labor-intensive and costly.

Table 4-3. Applications of Data Sources in Transportation Planning and Assessment
ToolDescriptionData NeedData Type&SourceStrengths, Limitations, or Desired Data
Envision Utah (63)Regional transportation-land use planning effort in northern Utah
  • Land use data
  • Property values
  • Environmental data (wetlands, slopes, floodplains, etc.)
  • Population and employment data
  • Traffic data
Data gathered and converted into GIS format from:
  • local comprehensive plans and state land use inventories
  • tax assessments
  • state environmental databases and satellite imagery
  • US Census, regional agencies
  • Traffic statistics (from DOT) and traffic generation rates (guidebooks)
  • Public feedback used to shape future scenarios
  • Land use scenarios input into custom travel demand model
Requires time and resources to prepare data files
Houston-Galveston Area Council's (H-GAC) Regional Decision Support System (RDSS) (78)

Funded under FHWA's Eco-Logical grant program, RDSS is an interactive, GIS-based mapping tool used to integrate long-range transportation and environmental planning. First consensus-driven, regional-scale tool for identifying priorities for future conservation. Incorporated into H-GAC's 2040 Regional Transportation Plan.

RDSS can be used for mapping on Internet Explorer with Adobe Flex viewer or ArcGIS users can stream the data into their own GIS projects.

Eco-types: ecosystems specific to the H-GAC region, including bottomland and upland forests, tidal wetlands, coastal prairies, and water bodies.

Landcover

Water quality data

2035 road network

Watershed data

Cumulative Metric Rankings

Other local and H-GAC data relevant to environment, transportation system, and growth

All data except ecotypes available in GIS format from H-GAC (landcover and road network), EPA (water quality, species), USGS (watershed)

Ecotypes were mapped using GIS - approximately 12,000 units mapped in 4 months

Cumulative Metric Ranking incorporates quantitative measures (like threatened and endangered species) and qualitative measures like ecotype quality (from observations using aerial photography and soil and geologic maps). Species indentified using EPA's Geographic Information System Screening Tool (GISST). Metrics and methodology for ecotype quality is described in the project report.

Scale of project was regional (8 counties), so limited mapping units to 100-acre minimum and thus could not map freshwater wetlands individually. Could not conduct on-the-ground verifications. Therefore, data not appropriate for site-specific evaluations.

Data is publicly available on Internet, so sensitive information such as threatened and endangered species could not be accessed.

Florida DOT's Efficient Transportation Decision-making (ETDM)(64)Process to anticipate environmental problems early on through public involvement and GIS assessment during planning, programming, and project development

Natural Resources

Cultural Resources

Community Resources

Transportation Project Information

Extensive data sets are compiled for each section in accordance with agency agreements and ETDM policies

Florida Geographic Data Library of University of Florida's GeoPlan Center (combines federal, state, local data from resource agencies, MPOs, FDOT, etc.)

Incorporate public feedback

Build database by transforming existing data into GIS format, using on-line data entry, or field data collection

GIS data may be incomplete or inadequate, requiring manual review of a project alignment; Requires coordination with multiple agencies at least annually to update; adhere to QA/QC measures
Idaho Transportation Department's Greenhouse Gas Emissions ReductionCalculating and tracking Idaho's transportation-related GHG emissionsGHG emissions from buildings, vehicles and equipment, and employee commutingEPA emission factors for buildings (electricity and heating), vehicle fleet and equipment, and employee commutes (data based on survey of employees)Establishing a baseline for future analysis
Minnesota DOT Performance Based Planning&Programming (65)Uses clear policy priorities, performance trend data, and performance forecasting to guide investment decisionsVarious performance measures related to transportation network performance and agency performanceRegularly collected DOT data (including crash statistics, freeway congestion, snow clearance, bridge condition); Transit bus hours (from cities, counties, or regional authorities)Measures are more linked to transportation system performance and will need to be expanded to evaluate progress toward sustainability
Missouri DOT Tracker (66)Quarterly report of measures for 18 outcome areas

% of projects without environmental violation

% of projects protecting sensitive species

Ratio wetlands created/impacted

% clean air days

Gallons of fuel consumed by unit

Historic resources avoided/ -protected vs. mitigated

Tons recycled materials used in construction

DOT data

DOT&USFWS

DOT data, Clean Water Act permits

EPA ozone readings

Statewide financial system

Collected by DOT during planning phase

MoDOT construction management database

Tracker utilizes existing and readily available data sources; additional sustainability focused measures would likely require new data sources
Montana DOT Highway Economic Assessment Tool (HEAT) (67)Enhanced benefit-cost analysis tool for projects that accounts for system impacts

Transportation system performance

Sociodemographics (block level data, including population, households, travel patterns)

Employment data at establishment-level and census tract and county level data

Commodity flows

Industrial profiles

Economic data including project cost estimates, value of time for freight movements (by commodity), travel times, economic attractiveness

GIS data repository compiled from public and private sources - U.S. Census, the State of Montana, Highway Performance Monitoring System, Bureau of Transportation Statistics (BTS), private data collection companies such as Reebie, Woods&Poole, Info USA

U.S. Department of Agriculture National Agricultural Statistical Service, Commodity Flow Survey (CFS), IMPLAN, 1997 Economic Census Data on Wholesale Trade, FHWA's Freight Analysis Framework (FAF)

Industry interviews

The tool is data intensive and combines multiple data sources; labor intensive to geocode data into GIS format; private data sources may not be free for use
MultiCriteria Evaluation of Planning Alternatives for Sustainability (62)Used in comparing metropolitan land use and transportation alternatives based on system performance, environmental, economic and social capital measures and tradeoffs.

20-year land use/transportation scenarios

System Performance Measures: VMT per capita; avg. distance driven per day per person

Environmental Indicators: VOC, NOx emissions

Economic Indicators: vehicle hours traveled per capita, avg. duration of driving per day per person

Social: Equity of exposure to emissions, population exposure to emissions

Atlanta Regional Commission:

GIS files&Excel data for land use

Four-step transportation demand modeling inputs and outputs for the Baseline 2005 conditions and Mobility 2030 plan

Evaluates relative rather than absolute sustainability value of different planning alternatives.
Public Transit Energy&Carbon Footprints (68)Estimation of the Energy and Carbon Footprints for Public Transit Systems in the 100 Largest U.S. Metropolitan Areas

Transit fuel consumption

BTUs and Carbon Emissions

FTA's National Transit Database (data reported by local agencies within metro areas)

US EIA published values (for liquid fuels) and estimated state carbon dioxide emissions from electricity generation (State Electricity Profiles)

Only as accurate as data collected by local agencies; aggregation error; missing data from local agencies
Sustainability Footprint(42)Used in analyzing the impacts of transportation infrastructure systems on regional sustainable development, in particular quality of life contributions

System Sustainability (Quality of Life) - congested travel (% peak vehicle miles traveled or VMT)

Waste generation - annual delay per person

Resource usage - annual excess fuel consumption

Texas Transportation Institute's Urban Mobility Report, comparing 1990 and 2000 dataSimplified footprint model - more robust measures would require additional data sources (like for safety, accessibility and other social benefits)
Transportation Energy&Carbon Footprints (69)Method to measure and compare (and potentially track) emissions for metropolitan areas

Daily VMTs

Fuel consumption for cars and trucks

Energy Use&Carbon Emissions

Urban Form Measures

HPMS&Highway Statistics (FHWA)

Oak Ridge Laboratory's Transportation Energy Databook, FHWA Highway Statistics, U.S. Census Bureau's 2002 Vehicle Inventory and Use Survey

US Energy Information Administration's (EIA) Published values

2000 Census, 2000 and 2005 County Business Patterns, 2000 and 2005 Zip Business Patterns, 2001 National Land Cover Database, FTA's 2005 National Transit Database

 
TxDOT Sustainability Indicators (30)Recently completed research project to develop sustainability indicators for the strategic plan

Performance Indicators like:

Travel Time Index

Annual severe crashes per mile

Land use balance

Truck throughput efficiency

Capacity addition within Right-of-Way

Daily carbon dioxide emissions

Calculated with DOT data

Estimation procedure based on Interim Roadway Safety Design Workbook

GIS land use files

% trucks from TxDOT's Road-Highway Inventory and Network

GIS analysis or physical inspection

Estimated by Mobile 6 Emissions Model

Indicators are more focused on transportation system performance rather than sustainability; based on mobility rather than accessibility and do not address social impacts; utilizes indirect measures that are derived from other variables
WSDOT Sustainability Plan&Progress Report (70)Annual plan update and progress report on sustainability targets and emerging issues

Agency performance in areas of:

Fleets and transportation

Purchase of goods and services

Paper recycling

Facility construction, operation, and maintenance

Persistent Bioaccumulative Toxins (eg. from herbicides)

Data from multiple DOT departments and other state or federal agencies including:

WSDOT Transportation Equipment Fund (for fuel consumption)

Washington State Ferries Safety Systems Office

WSDOT Systems Analysis and Program Development

WSDOT Purchasing and Inventory Total

WSDOT Regional Offices

Energy Information Administration

WSDOT Environmental Services

Primarily monitors internal agency sustainability
Updated: 03/27/2014
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