United States Air and Radiation EPA420-F-97-021
Environmental Protection December 1997
Agency
Office of Mobile Sources
v>EPA Environmental
Fact Sheet
Transportation Control Measures
Transportation Control Measures (TCMs), which have been in use for
several decades to control traffic congestion on major streets and
highways, are becoming increasingly popular as means to reduce net
vehicle emission by encouraging changes in the ways people travel.
What are Transportation Control Measures?
TCMs include a wide variety of measures used to reduce motor vehicle
emissions, primarily by reducing the total amount of vehicle miles of
travel (VMT) in an area. A few examples of TCMs include mass transit
improvements, ridesharing arrangements, telecommuting and work
schedule changes, parking management, and roadway tolls. Mile for
mile, most emissions from a car trip occur during the first 15 minutes a
car is running—the time when the emissions control devices are not
fully warmed up. Therefore, transportation control strategies that elimi-
nate or reduce short trips have the most emissions benefits.
It is clear how ridesharing and transit use reduce trips. Some other
transportation control measures are perhaps less obvious in how they
reduce emissions. Telecommuting allows a person to work from home or
a satellite work station closer to home than the normal work site. Parking
management can contribute to emissions reductions in several ways. For
example, reduced rates for carpool or vanpool parking can provide an
incentive for people to use those modes of travel.
®9 Printed on Recycled Paper
-------
Congestion pricing is an example of a market-based strategy whereby
there is a higher charge to use a stretch of road during peak travel times.
This is similar to the way airlines and telephone companies adjust prices
according to amount of demand. As a result, transit and ridesharing are
given a more equal economic footing compared to solo-driving; conse-
quently, more people would be expected to choose those ways of travel-
ing, thereby reducing emissions.
the in TCHs?
Technological improvements that have been made to motor vehicles'
emissions control systems since 1970 have resulted in substantial reduc-
tions in vehicle emissions on a per mile basis. However, technology has
reached a point where further refinements to emission controls would
produce only minor reductions in emissions, and at a large cost. Mean-
while, the number of vehicles on the road, and the number of miles they
are driven, has been increasing dramatically at the same time.
If present trends continue, the increase in vehicle emissions due to
increases in the total number of vehicles on the road, and the amount
they are driven, will overwhelm the benefits gained from improved
emission controls on vehicles. As a result, viable alternatives to single-
occupant driving need to be available and used in order to ensure the
healthy air quality we all need and to maintain the personal mobility we
all depend on.
is the of TCMs
Although EPA has no rules or regulations requiring that states or cities
implement TCMs, it is recognized that states face enormous challenges
to develop air quality control programs. States are required to develop
State Implementation Plans (SIPs) that demonstrate how the area will
reduce emissions and meet air quality standards. Many traditional
methods have proven benefits. However, due to the complexity of air
quality problems, additional measures are needed in many places.
This is where TCMs are beneficial. Because TCMs have only recently
been viewed as tools to improve air quality, their environmental benefits
are still being analyzed. EPA is gathering information on the effective-
ness of TCM programs, either individually or in combination, in im-
-------
proving air quality so that they can be used to the best effect. Many areas
have moved ahead in implementing a variety of TCMs such as employee
ridesharing programs, guaranteed ride home programs, transit improve-
ments, and others. In a number of areas around the country, TCMs are
used as part of episodic control programs, often called "Ozone Alert," or
"Ozone Action" programs.
EPA is developing guidance that will help more areas implement such
programs and take credit for them in their efforts to meet air quality
standards. EPA has also been working through its "Transportation
Partners" program to encourage effective and innovative transportation
alternatives through grants and awards.
For
For more information on transportation control measures, please contact
Erik Herzog at:
U.S. Environmental Protection Agency
Office of Mobile Sources
2000 Traverwood Drive
Ann Arbor, MI 48105
Phone: (734)214-4487
Fax: (734)214-4052
E-mail: herzog.erik@epa.gov
Information on episodic control programs can be found on the EPA
Internet World Wide Web (WWW) site at:
http://www.epa.gov/oms/reports/episodic/study.htm
Information on the Transportation Partners program can be found at:
http ://www. epa.gov/oppe/tp/
This fact sheet and additional information on transportation and air
quality are available at:
http ://www. epa.gov/oms/traq
------- |