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Smart Growth Area Planning Tool (SmartGAP) At A Glance

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March 2014

The Effect of Smart Growth Policies on Travel Demand

Developed through the second Strategic Highway Research Program (SHRP2), the Smart Growth Area Planning tool (SmartGAP) provides planners with scenario-forecasting tools that allow them to estimate smart growth strategies impact on peak-hour transportation, as well as its effects on sprawl, energy reduction, active travel, and carbon footprints.

Overview of SmartGAP

The SmartGAP tool allows a user to test different scenarios for land use, population growth, and transportation strategies, and then evaluate their effects on several significant performance measures. SmartGAP tracks individual households and firms in a region to determine transportation impacts from growth. The tool has several advantages:

SmartGAP considers 13 built environment place types and features that address the complexity of land use and transportation interactions:

Place Types for Households and Firms in SmartGAP

Title: Place Types for Households and Firms in SmartGAP - Description: SmartGAP includes 13 different place types which are a combination of 5 different development types and 4 different area types. Development types include residential, employmetn, mixed use, transit oriented development and rural/greenfield. Area types include urban core, close in community, suburban, and rural. Thirteen of the possible twenty combinations are included in SmartGAP.

SmartGAP Graphical User Interface

  1. Drop down menus for project and scenario management and help
  2. "Inputs", "Outputs", and
  3. Run button executes complete model
  4. "Model Flow" showing model components
  5. Individual inputs that can be selected, edited and commented

Title: SmartGAP Graphical User Interface - Description: The figure shows a screenshot of the SmartGAP software graphic user interface. The GUI includes a Project, Scenario and Help menu items along with Inputs, Outputs, and Reports tabs to select different files and model parameters.

Performance Metrics

SmartGAP's performance measures are designed to address a variety of impacts useful for decision-making.

Direct Travel Impacts (1) Daily Vehicle Miles Traveled, (2) Daily Vehicle Trips, (3) Daily Transit Trips, (4) Peak Travel Speed by Vehicle Type, (5) Vehicle Hours of Travel, and (6) Vehicle Hours of Delay.
Environment and Energy Impacts (1) Fuel Consumption and (2) Greenhouse Gas Emissions.
Financial and Economic Impacts (1) Regional Highway Infrastructure Costs, (2) Regional Transit Infrastructure, (3) Annual Traveler Cost (Fuel + Charges), and (4) Annual Transit Operating Costs.
Community Impacts (1) Accident Rates, (2) Walking Percentage Increase, and (3) Job Accessibility by Income Group.
Local Impacts Regional Accessibility.

The performance measures are reported in SmartGAP's output data files. The metrics can also be charted using the reporting tab in SmartGAP, which also includes the ability to compare the results across scenarios.

Pilot Tests

SmartGAP is a decision support tool for planners to test smart growth scenarios and evaluate their impact on travel demand. The software is designed to be accessible to land use and transportation planners with no modeling experience. In certain cases, the tool can be applied to supplement more sophisticated modeling methods.

TheSmartGAP tool was piloted by the following planning agencies:

Results from the pilot tests indicate that:

Title: SmartGAP Pilot Test sample results - Description: The figure contains two bar charts showing a comparison of vehicle hours of delay by sample scenarios (8 scenarios) and a comparison of daily transit trips by sample scenarios (4 scenarios). The change in vehicle hours of delay in Atlanta decreases most with additional lane miles and ITS to reduce congestion. The transit trips in Olympia shows how the transit trip metric is based on land use effects.

Distribution and Use of SmartGAP

SmartGAP offers a reliable tool that transportation and land use planners can use to better understand how smart growth strategies will influence travel demand, the environment, the economy, and local communities. This capability reports smart growth benefits from induced travel and from both peak and off-peak travel.

Updated: 05/13/2014
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