Report PDF - US Environmental Protection Agency

Chapter 4
Assumptions Significantly
Overestimated Project Results
TDOT complied with the cooperative agreement requirements and satisfied
Region 4 requirements for determining project results. However, TDOT
overstated its results. This occurred because TDOT utilized significantly
overestimated usage assumptions in its projections rather than using actual usage
data. As a result, TDOT does not have reasonable assurance that the TSE project
will achieve its projected emissions reductions. The project may not achieve
expected environmental results and human health benefits. Further, the DERA
program results may be overstated.
Usage Assumptions Were Significantly Overestimated
TDOT utilized assumptions that were significantly overestimated based on project
usage data available at the time of the TSE project final report. The assumptions
include:
The use of estimated hours rather than actual hours of operation.
The use of installed facilities rather than operable facilities.
TDOT initially proposed the installation of a network of 175-200 electrified
parking spaces. For 200 spaces, TDOT projected reductions in air pollution
including 60.32 tons per year of NOx; 1.72 tons per year of particulate matter;
and 3,552 tons per year of carbon dioxide. TDOT also projected a savings of
approximately 350,000 gallons of diesel fuel per year. TDOT calculated the
reductions, as encouraged by EPA’s grant solicitation, using the diesel emissions
quantifier. The calculations required TDOT to make assumptions regarding the
use of the facilities. TDOT assumed truck drivers would use the facilities for
8 hours per day for an average of 250 days per year. TDOT used the National
Deployment Strategy for Truck Stop Electrification, 7 published in 2006, and the
federal Hours of Service Regulations 8 as the basis for these assumptions.
Per the TSE project final report, dated February 28, 2012, TDOT installed 117
spaces rather than the 175-200 spaces proposed. While the TSE project final
report discussed the various reasons for not installing the proposed 175-200
spaces, TDOT initially did not revise its projected results to reflect the actual
7
Study conducted by the Texas Transportation Institute under a grant funded by EPA.
8 U.S. Department of Transportation, Federal Motor Carrier Safety Administration, Sleeper Berth Provision,
requiring at least 8 consecutive hours in the sleeper berth.
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