The
Clear Air Act Amendments of 1990 require
that transportation plans and programs are
consistent with efforts to attain air
quality standards. Nonattainment areas must
demonstrate that their long-rang
transportation plan and short-range
transportation improvement programs (TIPs)
are in conformity with the area’s State
Implementation Plan (SIP).
In
estimating the air emission on road network,
it is a common practice to consider the
emissions caused in the general cases of
transportation operations including the
recurring congestion, with a few
considerations of the impacts of
nonrecurring congestion due to accident.
Nonrecurring
congestion in urban areas due to vehicle
accidents is a large cause of increased
delay, increased road user costs, and
increased mobile source emissions.
Motor vehicle emission budgets and
project analysis in nonattainment areas
relay on regional travel demand model
results and subsequent mobile source
emissions estimates.
Regional mobile source emission
estimates might be improved when impacts
from nonrecurring congestion due to
accidents are used.
The frequency and severity of
nonrecurring incidents on urban roadway
sections could be developed and associated
with estimated travel and emissions results.
The
objective of this research is to examine and
identify the data, methods, and tools
necessary to integrate nonrecurring
congestion from accidents into
transportation and air quality modeling.
Since accidents and the nonrecurring
congestion caused are small probability
events. The conventional analytical models
and approaches are based on either the
simple regress analysis, or traditional
probability analysis. This research intends
to apply the Bayesian Approach onto the
analysis of the Department of Public Safety
county-level accident data. The accidents by
day of week, hour of day, the lanes blocked
per accident, and etc. is to be analyzed by
the discrete case of Bayesian Approach;
while the accident duration is to be
analyzed by the continuous case of Bayesian
Approach. Finally, the process for air
quality impacts of nonrecurring congestion
is to be conducted and documented to TxDOT.
