Tom Kear

SUBJECT: TCM
Information


This memo is in response to your request for help identifying information resources related to
Transportation Control Measures (TCMs). You had asked us to put together (a) a list of
useful resources (literature) that would help quantify emission reductions associated with
TCMs, and (b) a brief list of tasks that would represent a TCM analysis effort. The context
was the potential need for Caltrans to assist in evaluating reasonably available control
measures (RACM) for the San Joaquin Valley.

TCM Literature Identifying Emission Reduction Benefits

There is a wide range of literature available on how to evaluate TCMs and quantify the
emission reduction benefits. Rather than provide a detailed listing of the various documents,
as a first step it is useful to identify major web sites with TCM-related literature. Important
sites include

1. As a general reference, the U.S. EPA has a web site that identifies TCM-specific
resources. EPA information is available at:
http://yosemite.epa.gov/aa/tcmsitei.nsf
.

2. FHWA also has a TCM web site, located at:
http://www.fhwa.dot.gov//////environment//tcm.htm
.

3. FHWA has sponsored preparation of several guidance documents on TCM evaluation
methodologies. The most recent is dated October 2000 and is available from the
Internet at:
http://www.fhwa.dot.gov//////environment//tcm3.htm
(click on A
Sampling of Emissions Analysis Techniques for TCMs; this site also has other
emission evaluation resources).
4. ARB also has a web site which makes available various tools to do cost-benefit
analyses of CMAQ projects and various specific TCMs (employer programs, street
sweeping and others). Information is available at:
http://arbis.arb.ca.gov/planning/tsaq/eval/eval.htm
.

Assuming that the RACM TCMs have already been identified for evaluation, perhaps the
single most useful resource at this point would be the FHWA-sponsored A Sampling of
Emissions Analysis Techniques for TCMs (available at:
http://www.fhwa.dot.gov//////environment//cmaqeat/cmaqeat.pdf
). This document includes
various tables which identify, by specific TCMs, the relative merits of the various analysis
tools available.

Task Considerations

A brief checklist of things to do to complete TCM emission assessments could include the
following steps:

1. Identify TCMs for analysis; identify appropriate and available analysis tools using
overview resources such as those from FHWA (i.e., A Sampling of Emissions
Analysis Techniques for TCMs) or EPA (i.e., TCM evaluation matrix, available via:
http://www.epa.gov/oms/transp/vmweb/matrix.pdf
).

2. Obtain needed local data on base-year and future-year base-case travel activity.

3. Identify TCMs already being implemented or those already committed to for future
implementation. (This information will be needed to appropriately apportion the
fraction of travel activity that could be affected by implementation of additional
TCMs; see Step 5 below).

4. Interview local agency staff responsible for implementing identified and candidate
TCMs. In most cases, local agencies have already implemented similar or identical
measures in the past, and discussions with local staff are needed to identify the
potential incremental changes that are practical with additional TCMs. For example,
regional planning agencies may have already identified parcels of land available for
additional park and ride facilities; future park and ride lot implementation would be
governed by these parcel locations and the number of parking spaces they can
accommodate.

5. Determine degree to which TCMs overlap in terms of travel activity affected, and
apportion relative activity to be affected by individual measures. For example,
implementation of a telecommuting program could eliminate some trips that might
have been affected by improved transit service; activity needs to be apportioned
correctly to avoid double counting of program benefits.

6. Employ specific analysis techniques identified through the literature. Steps are likely
to include off-model adjustments to a small subset of travel, and should account for emission reduction benefits associated with changes in trip end activity (starts and
starts), vehicle miles traveled, and travel time changes.

7. Share draft findings with local agencies for review and discussion.

8. Prepare final study report.


This is obviously a very brief overview of what constitutes a large base of literature. Let us
know how you would like us to refine or expand upon the information provided.