55 mph Speed Limit to Lower Greenhouse Gas Emissions in Washington State

Transportation causes almost half of Washington's greenhouse gas emissions. Lowering the speed limit to 55 mph would cut vehicle emissions by at least 10%. According to the Governor's Climate Action Team, most cars and light trucks on the road today reach optimum fuel efficiency between 45 and 55 mph. Driving slower also reduces the incidence and severity of traffic accidents. For 21 years, from 1974-1995, the speed limit was 55 mph in response to the mideast oil crisis. We can drive 55 again to address the emergency of climate change.

The Climate Action Team wrote in their December 21, 2007 Draft Recommendations to the Governor:

“If there’s no action before 2012, that’s too late. What we do in the next two to three years will determine our future. This is the defining moment.”

And they commited to pursue the "low hanging fruit" first.

Reducing the speed limit to 55 mph would reduce vehicle emissions by at least 10% right now, without the need for technological development and at low cost.

Despite all this, the Technical Working Group on Transportation dropped the 55 mile speed limit over the objections of TWG members. Call on the Climate Action Team to reinstate the 55 mile speed limit as one of the proposed actions in the final recommendations to the Guvernor and for legislation in the 2008 session.

YOUR COMMENTS ARE NEEDED to Governor Gregoire's Climate Action Team:

On the web at: http://www.ecy.wa.gov/forms/wr/draft_comment1.html

By e-mail at: climatecomments@ecy.wa.gov


BACKGROUND: 

In the December 21, 2007 Draft Recommendations of the Washington Climate Advisory Team http://www.ecy.wa.gov/climatechange/CATdocs/122107_1_recommendations.pdf,

they write that "transportation is nearly half of Washington's emissions," and on page 5 they write that due to the emergency of global warming we have two to three years to make changes:

“If there’s no action before 2012, that’s too late. What we do in the next two to three years will determine our future. This is the defining moment.” Rajendra Pachauri, head of the IPCC and 2007 Nobel Peace Prize Laureate, issued this call to action upon the release of the United Nations Intergovernmental Panel on Climate Change (IPCC) fourth and final report on November 17, 2007.4 The IPCC is the scientific body charged by the U.N. with providing objective information about climate change. The fourth IPCC report combines scientific data from three previous IPCC reports, and their comprehensive synthesis creates a striking sense of urgency.5

On page 14 they commit to pursuing "low hanging fruit."

Reducing the speed limit to 55 mph would reduce vehicle emissions by at least 10% right now, without the need for technological development. “Most cars and light trucks on the road today reach optimum fuel efficiency between 45 and 55 mph” (December 21, 2007 CAT report). This is further confirmed by Jason Mark, clean vehicles program director for the Union of Concerned Scientists. “For every mile per hour faster than 55 mph, fuel economy drops by about 1 percent. The drop-off increases at a greater rate after 65 mph. The faster you go, the faster the fuel goes” (http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2005/10/19/MNG3NFAOF11.DTL).

Reducing the speed limit to 55 mph is “low hanging fruit” and must be included in the CAT recommendations to the Governor and legislation coming out of that report.

Reducing the speed limit would also reduce the incidence and severity of crashes:

Speed Limits and Safety

Another way to examine the relationship between vehicle speed and traffic safety is to measure the effects of lowering or raising speed limits on the incidence and severity of crashes. Table 3 summarizes the results of studies of this type conducted in several countries. The table shows that crash-incidence or crash severity, or both measures, generally decline whenever speed limits have been reduced. Conversely, the number of crashes or crash severity generally increased when speed limits were raised, especially on freeways.


Speed and the Severity of Crashes

The relationship between vehicle speed and crash severity is unequivocal and based on the laws of physics. The kinetic energy of a moving vehicle is a function of its mass and velocity squared. Kinetic energy is dissipated in a collision by friction, heat, and the deformation of mass. Generally, the more kinetic energy to be dissipated in a collision, the greater the potential for injury to vehicle occupants. Because kinetic energy is determined by the square of the vehicle's speed, rather than by speed alone, the probability of injury, and the severity of injuries that occur in a crash, increase exponentially with vehicle speed. For example, a 30-percent increase in speed (e.g., from 50 to 65 mi/h [80 to 105 km/h]) results in a 69-percent increase in the kinetic energy of a vehicle (http://www.tfhrc.gov/safety/speed/speed.htm).

Power to Reduce the Speed Limit Lies with the States

Historically, the power of setting speed limits belonged to the states. As an emergency response to the 1973 oil crisis, the U.S. Congress and President Richard Nixon imposed a nationwide 55 mph (90 km/h) speed limit in 1974 by requiring the limit as a condition of each state receiving highway funds. Congress lifted all federal speed limit controls in the November 28, 1995 National Highway Designation Act, fully delegating speed limit authority to the states. For twenty-one years, Americans drove 55 mph in response to a national emergency. Washington State can and must reduce the speed limit to 55 mph to respond to the emergency of climate change.

Despite the fact that reducing the speed limit to 55 mph would reduce at least 10% of GHG emissions, reduce the incidence and severity of accidents, is low cost and could be implemented quickly, and was successfully implemented nationwide for 21 years from 1974 to 1995, “the strategy was removed over the objection of some workgroup members” (December 21, 2007 CAT report, page 70.)

Please see the quotes from the December 21, 2007 CAT report:

http://www.ecy.wa.gov/climatechange/CATdocs/122107_TWG_trans.pdf

Page 64

Several factors influence automobile efficiency including aerodynamics and engine design. Most cars and light trucks on the road today reach optimum fuel efficiency between 45 and 55 mph. The workgroup discussed the link between fuel efficiency and speed. The group considered suggesting a change in speed limits as a part of this mitigation option, but the group did not reach agreement. For more information on the issue of reducing speed limits on state routes and interstates, see the Feasibility section.

Pages 69-70

Feasibility Issues

In addition to the individual strategies described above, the workgroup considered a strategy that would reduce speed limits on highways in order to improve fuel economy and reduce GHG emissions. As noted above, most vehicles operate at maximum fuel efficiency between 45 and 55 mph.

WSDOT’s State Traffic Engineer provided a list of concerns regarding the feasibility of and potential risks associated with this strategy. These concerns included the following:

Artificially lowering a 65 or 70 mph speed limit by 10 or 15 mph would not necessarily result in a significant reduction in operating speed.

A speed limit reduction could create safety problems and more collisions as some drivers obey a new 55 mph speed limit and other drivers continue to operate at high speeds. A large difference in speed between drivers causes unexpected maneuvers and leads to collisions. The Washington State Patrol does not have the resources to enforce a 55 mph speed limit.

WSDOT/WSP/Legislature have placed significant emphasis on safety within highway work zones, which includes compliance with posted speed limits. Artificially lowering regulatory speed limits statewide damages the credibility of all of the signs that are posted, which could be detrimental to the desire for compliance within workzones.

In response to these concerns, the strategy was removed over the objection of some workgroup members.

Conclusion

It is hard to believe that the Washington State Patrol could not enforce a 55 mph speed limit. They did it for twenty-one years 1974-1995. The State can include in the legislation public education about the benefits of reducing carbon to the atmosphere by driving slower. People want action. Our future is threatened.


“What we do in the next two to three years will determine our future. This is the defining moment.” Let's call on the Climate Action Team to include the 55 mph speed limit in the final CAT recommendations to the Governor.

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