January 7, 1989
George Gray, Deputy District Director
California Department of Transportation
P.O. Box 7310
San Francisco, California 94120-7310
Re: 1988 Caltrans District 4 State Highways: System Management Plan
Since writing you on November 27, 1988 on this subject, I have discovered some very interesting research that has a great bearing on the SMP and on all other highway planning. J.R. Kenworthy, H. Rainford, P.W.G. Newman, and T.J. Lyons, in their September, 1986 paper "Fuel Consumption, Time Saving and Freeway Speed Limits" in Traffic Engineering and Control, demonstrated that maximum fuel efficiency occurs at 55 kph (34 MPH). I had thought that maximum fuel efficiency occurred at 55 MPH, and therefore had never questioned fuel savings claims made in highway planning documents. This new information implies that claims of fuel and dollar savings that were based on speeding up traffic above 34 MPH are invalid.
For example, on page S 11 of the SMP, you state "The environmental impacts considered were: (1) fuel consumption .... In all cases, freeway operations are optimized when vehicle speeds in excess of 40 miles per hour (LOS D) are attained." This is simply not true. As the above-mentioned research shows, fuel consumption is minimized at 34 MPH (LOS E). On p.6 is the assertion: "Congestion is also detrimental to a clean and healthful environment." This is also not necessarily true. While an individual vehicle may produce less CO at higher speeds, the increased fuel usage and increased freeway capacity (more cars per hour) would seem to increase pollution levels. It should not be too hard to program a computer to determine the speed at which total pollution is minimum, based on this new information. It would probably be below 40 MPH.
On page S 19 is the statement "Implementation of the four SMP strategies is estimated to significantly reduce congestion on freeways and local streets and roads which will result in less time delay, improving fuel efficiency and reducing vehicle emissions." This statement should be eliminated. The increased vehicle speed, as I indicated in my last letter, will be very short-lived. And there will be no fuel savings above 34 MPH, nor pollution savings above 40 MPH. Of course, the traffic inducement discussed in my last letter will ensure that there are no savings of any type.
This gives further evidence that the Fuel Consumption savings listed in table 5.30-2, on p.228, are grossly exaggerated. As I indicated in my last letter (for other reasons), there won't be any fuel savings. Instead, there will be a net increase in fuel usage.
The bottom line is that freeway expansion has no benefits for the public at all. The only benefits are to Caltrans (more money for freeway planning), freeway builders, and the oil companies (who will sell more gasoline). This again underlines the conclusion that rail transit is the only answer to the congestion problem. Trains can travel much faster than any car, and much more safely. Automobile accidents increase in number and severity with speed, another reason to keep auto traffic at 34 MPH.
What is my vision for the future of transportation? High-speed rail transit along every major corridor, with light rail and feeder buses making frequent connections within walking distance of every location where people want to go. High speed transit service, combined with more realistic pricing of auto travel (eliminating the hidden subsidies and including the environmental costs) can provide for nearly all of our transportation needs, without destroying our health and the environment. My advice to Caltrans is to start learning how to provide this kind of service.
Michael J. Vandeman, Ph.D.