Emissions Analysis Techniques for TCMs
Overview - The North Central Texas Council of Governments (NCTCOG) applied a set of sketch-planning procedures to assess the emissions benefits of TCMs implemented in an air quality attainment plan for the Dallas-Fort Worth metropolitan area.
Strategies Addressed - Improved transit; HOV lanes; park and ride; carpooling and vanpooling promotion; employer-based TDM; bicycle and pedestrian facilities; traffic flow improvements; incident management; alternative fuel vehicles.
Methodology - The procedures are at a sketch-planning level with data sources, assumptions, and basic equations described in a report. The procedures are applied to analyze specific projects or sets of projects.
Data Requirements - Inputs vary by project type but typically include extent of project (i.e., miles of HOV or bike lane), average before and after travel speeds, traffic volumes, ridership levels or participation rates, trip lengths, and emission factors by speed. Empirical data on impacts for similar projects (or simulations for traffic flow projects) are used to develop or verify assumptions for most strategies.
Outputs - Changes in emissions.
Level of Effort - The calculation methodologies are generally straightforward and easy to apply. Some effort may be required to conduct data collection or to identify existing studies from which to draw assumptions.
Advantages - The document illustrates some simplified techniques for developing project-level emissions estimates. Assumptions on travel behavior and traffic flow impacts were developed or validated based on real-world observations of similar implemented strategies. The document describes the types of studies undertaken to develop the inputs to the sketch-planning procedures.
Limitations - The methods generally do not forecast travel demand or traffic flow impacts directly, but instead require the user to identify reasonable assumptions about these impacts. Trip-based emissions impacts are not considered.
Source/Availability - Transportation Control Measure: Effectiveness Study. Technical Report Series No. 44, North Central Texas Council of Governments, Arlington, TX (August 1996). Contact the Regional Information Center (817-640-3300, http://www.dfwinfo.com/publications.html).