Speed Limit Fears: Lying with Science

By Ben Langlotz
Jan 7, 1996

[To encourage skepticism] here is the list from the press release section of an Insurance Industry Lobbying Organization "Advocates for Highway and Auto Safety" that wants to keeps charging average safe drivers those bonus premiums for getting dinged in speed traps by officers using detection equipment paid for by the insurance industry.

I can only address the sound bites that they chose to include. Without the studies or data before us we can only argue in the hypothetical. The purpose of this discussion is not to disprove their soundbites, but to encourage skepticism of unsubstantiated fear tactics.

1.The National Academy of Sciences concluded that the National Maximum Speed Limit saved between 3,000 and 5,000 lives in 1974, and between 2,000 and 4,000 lives each year through 1983. The study predicted 500 more deaths annually if rural interstate speed limits were raised to 65 mph. 55: A Decade of Experience, Transportation Research Board Special Report No. 204 (1984).
Of course, from 1974 to 1983, the fatality rate dropped from 3.5 to 2.6 (deaths/million vehicle miles), and today, after the increase of limits to 65 in 1987, and the increase in ACTUAL speeds everywhere, the fatality rate is 1.7. Half of what it was in 1974!
2.The U.S. Department of Transportation concluded, based on 1993 data, that fatalities on 55 mph highways decreased by 4.5%, while fatalities on 65 mph highways increased by 2.4%. A Report of the Secretary of Transportation to the United States Congress, Federal Highway Administration (Oct., 1995).
Ever consider that this is entirely consistent with 65 mph roads having a MUCH lower death rate than 55 mph roads? Suppose that the truly dangerous two lane country highways had a drop in fatalities from 10,000 to 9550 due to reduced drunk driving, while the fast interstates had an increase from 1600 to 1638. Does that make the 55 roads safer? Of course not. What is the fatality RATE for the two types of roads? The insurance flaks don't seem to want to talk about that.
3."All studies of national effects . . . indicate that fatalities have increased on rural Interstates by roughly 15-25%, resulting in approximately 300-500 additional deaths on highways posted at 65 m.p.h. in 1988. Effect of The 65 M.P.H. Speed Limit on Highway Safety in The U.S.A., Godwin, S.R., Transport Reviews, vol.12 no.1 (1992).
If 300 is 15% and 500 is 25%, then they are admitting that there are only 2000 fatalities on these fast interstates per year. Yet they also claimed that the increase of the limit from 55 to 65 on these roads led to an increase in deaths of 6000 per year. This is their basis for their claim that deaths will increase another 6000 with another raise of 10 mph.
4.In 1990, thirty percent (30%) more people were killed on rural Interstate highways posted at more than 55 mph than would have occurred if the 55 MPH speed limit had been maintained. Effects of the 65 MPH Speed Limit Through 1990: A Report To Congress, National Highway Traffic Safety Administration DOT-HS-807 840 (May, 1992).
Yet somehow the national fatality rate set a new record low that year.
5."Speeding/excessive speed is one of the most prevalent factors contributing to crash occurrence. It is estimated to be INVOLVED in approximately 12 percent of all police-reported crashes. . . In 1989, it is estimated that about 15,558 fatalities and 80,000 serious physical injuries occurred in speed-related crashes." Data Analysis of the Speed-Related Crash Issue, Bowie & Walz, 13th International Conference on Experimental Safety Vehicles (Nov., 1991). (caps emphasis added)
And suppose that 10,000 crashes INVOLVED drivers who had consumed fruit juice that morning. It is poor science to confuse correlation with causation. When a drunk driver going with traffic at 65 mph in a 55 mph zone kills himself by running off the road, it gets counted as a "speed related" fatality.
6.On Michigan roads where the speed limit was raised fatalities rose 28%, serious injuries increased 39%, and moderate injuries went up 24%. Effects of The 65-MPH Speed Limit on Crashes and Crash Casualties in Michigan: 25 Months of Experience, Streff & Schultz, UMTRI, AAMA 35th Annual Proceedings (Oct., 1991).
More science problems. There will always be random variations in this type of data. If the National data doesn't fit your lobbying goals, scour the country for a few anomalous states. And then, only use two years' random variation in the data, not a meaningful long term trend. Also, measure only SOME roads in your state, so you miss the beneficial effect of your drivers using the interstates instead of dangerous two lane highways. In most states, the increase in interstate usage led to correspondingly more accidents, but this was more than compensated for by the greater reduction on other roads. Only a look at the big picture shows the truth.
7.In Georgia, both fatalities and fatal accidents increased in 1989 as a result of the 65 mph speed limit, overwhelming the safety benefits of increased safety belt use. Safety Effects of The 65 MPH Speed Limit and a Mandatory Seat Belt Law in Georgia, Wright, et al., AAMA 35th Annual Proceedings (Oct., 1991).
One year, one state. Next?
8.In 1989, there were 600 more fatalities, an increase of 32%, on rural interstates in states that raised the speed limit to 65 compared to the mean rate in the five years (1982-86) before the speed limit increase. Two-thirds of the deaths (almost 400), a 19% increase in fatalities, were directly attributed to increased speed limits. The Fatality Rate Consequences of The 65 MPH Speed Limit, 1989, Baum, Wells & Lund, IIHS (Apr., 1991).
In 1982, there were 1.6 trillion vehicle miles traveled in the US, in 1989, it increased 31% to 2.1 trillion. Coincidence? When they talk of fatalities, not fatality rates, be suspicious!
9.The rate of injury causing accidents increased between 1986 and 1988 on rural interstates posted at 65 mph. Average vehicle speeds increased by 4 mph and the 85th percentile speed increased by almost 5 mph in the same time period. Effect of the 65 MPH Speed Limit On Travel Speeds and Related Crashes, Mace & Heckard, DOT-HS-807 764 (Mar., 1991).
They conveniently fail to mention by HOW MUCH the injury rate increased. We do know that the national fatality rate decreased by 7.5% during the same period.
10.In 1989 there was a 19% increase in the number of fatalities directly attributable to speed limits posted above 55 mph. The Effects of The 65 MPH Speed Limit Through 1989: A Report To Congress, National Highway Traffic Safety Administration, DOT-HS-807 706 (Dec., 1990).
This is repeating the questionable data of #8 above.
11.Increases in fatal accidents were noted on "look-a-like" rural freeways posted at 65 mph. Accidents Before and After the 65 MPH Speed Limit in California (Supplemental Report), Smith, R.N., California Dep't of Transp. (Oct., 1990).
Where are the numbers?
12.Higher maximum speed limits increases the number and percentage of vehicles that speed. Speeds Associated With the 55 MPH and 65 MPH Speed Limits In Northeastern States, Freedman & Williams, IIHS (Aug., 1990).
Think about this. It has nothing to do with safety. They are saying that more people will exceed a higher limit than will exceed a lower limit. Hello?
13.Higher speed limits cost approximately 530 more lives in 1989. Motor Vehicle Crash Fatalities and 65 MPH Speed Limits on Rural Interstates in 40 States, Lund, Wells & Baum, IIHS (Aug., 1990).
Between 1986 (the first full year prior to the rise to 65) and 1988 (the first full year after,) the fatality RATE dropped 2.6% in those states that kept the 55 mph limit, and dropped an average of 6.15% in the 40 states that raised limits to 65 mph. See #24 below for Dr. Lave's conclusions in his study funded by the AAA Foundation for Traffic Safety.
14."The estimated effect of higher speed limits in 1988 based on all 40 states translates into 531 to 566 deaths attributable to the higher speed limit." Motor Vehicle Crash Fatalities in The Second Year of The 65 MPH Speed Limits, Baum, Wells & Lund , J of Safety Research vol.21 no.1 (Spring, 1990).
Another rerun of #13. I guess they really couldn't come up with 27 pieces of evidence. They had to repeat a few favorites.
15."Results clearly revealed significant increases in crash-induced injuries on road segments where the maximum speed limit increased from 55 mph to 65 mph." Effects of The 65 MPH Speed Limit On Injury Morbidity and Mortality, Wagenaar, Streff & Schultz, Accid. Anal. & Prev., v.22 no. 6 (Mar., 1990).
"Clearly" significant enough for insurance companies, but not enough that they print the numbers.
16.Higher speed limits increase the number of high speed violators. The Effect of The 65 MPH Speed Limit on Speeds in Three States, Freedman & Esterlitz, IIHS (Jan., 1990).
Another duplicate of Freedman's absurd conclusion noted in #12.
17.Increased speed limits on rural interstate highways coincided with a 48% increase in speeders and a 22% increase in fatal accidents on those same roads. The Relationship of the 65 MPH Limit To Speeds and Fatal Accidents, McKnight & Klein, TRB 69th Annual Meeting (Jan., 1990).
This may be entirely explained by increased vehicle miles. And don't tell me that the increase in speeders is measured by the increased number of troopers out there doing fundraising. Not a scientific way to measure. At least they had enough restraint to use the term "coincided." not "caused."
18.Analysis noted increase in the total number of accidents and in the rate of fatal accidents occurring in 1987-88 versus four (4) years previous to speed limit increase. Safety and Operational Impacts of Raising The Speed Limit To 65 MPH. Final Report., Upchurch & Rahman, Arizona Dep't of Transp. (Apr., 1989).
Maybe in Arizona, but not in the rest of the nation. And don't you wonder if those alarming 87-88 numbers include the portion of 1987 BEFORE the limit was raised?
19.In the first year of the 65 mph speed limit, there was "strong evidence that overall accident frequency increased slightly more than 14%" and that the 85th percentile speed increased by 4-5 mph. The Safety Impact of The 65 MPH Speed Limit - A Time Series Analysis. Final Grant Report., Pfefer & Stenzel, DOT-HS-807 524 (Dec., 1989).
"Accident frequency"? How about rates per vehicle mile? They went down, even if there were more accidents per hour during this period of increasing traffic.
20.In 1987 there was a 10% increase in the number of fatalities directly attributable to speed limits posted above 55 mph (speed limits were raised for only part of the year). In 1988, the first full year at higher speeds, there were 21% more fatalities directly attributable to higher speed limits. Report To Congress On The Effects Of The 65 MPH Speed Limit Through 1988, National Highway Traffic Safety Administration (Oct., 1989).
Wait a minute. The limit wasn't raised on January 1, 1987, was it? So this study has before and after dates confounded together, yet maintains certainty that the fatalities were "directly attributable."
21."Between April 2, 1987, and April 1, 1988, there was a significant increase in the rate of fatal motor vehicle crashes on rural Interstates in New Mexico compared with the 5 previous years." Effects of the 65-MPH Speed Limit On Rural Interstate Fatalities In New Mexico, Gallagher, et al., JAMA, v.262 no. 16 (Oct., 1989).
Drunk driving, drunk driving, drunk driving. What's speed got to do with it?
22."[T]he 65 mph limits increased rural interstate fatalities in 1987 by approximately 15 percent, there was no evidence of a similar trend in states that retained 55 mph limits, and the increase was not limited to only a few states." The Mortality Consequences of Raising the Speed Limit to 65 MPH on Rural Interstates, Baum, Lund & Wells, AJPH, vol.79 mo.10 (Oct., 1989).
These are the folks who did the research for # 8, 13, and 14 above. They seem to be getting a lot of consulting work from the insurance industry while fatality rates are going down.
23."In the states raising their limits to 65 mph, speeding on rural interstate highways increased by 48% and fatal accidents by 22% over projections based upon prior trends." The Effect of the 65 MPH Limit on Speed and Accidents, J.A. McKnight, et al., DOT-HS-807 463 (Aug., 1989).
A duplicate of #17.
24."For rural Interstate fatalities the estimates suggest a median (among the 40 states) effect of the increased speed limit of roughly 15% more fatalities." The Effects of the New 65 Mile-Per-Hour Speed Limit on Rural Highway Fatalities: A State-by-State Analysis, Garber & Graham, DOT-HS-807 452 (July, 1989).
The data from this study was reanalyzed by Charles Lave, the Chairman of the UC Irvine economics Department. After substituting fatality rates for total fatalities, and using statewide numbers instead of selected roads, he concluded that the raise in limits actually lowered fatality rates by 5 to 10%.
25.Using a conservative 16% figure for increased fatalities one study concluded that "[t]he 65 mph speed limit costs more time than it saves. It also costs the public and the insurance industry almost twice as many dollars as it saves the trucking industry." 65 MPH: Winners and Losers, T.R. Miller, DOT-HS-807 451 (July, 1989).
I suppose they concluding that we are slowed more by rubbernecking at accidents, and waiting for funeral processions. Trouble is, the fatality rate is still going down. When you compare the time saved by going 75 instead of 55 for 150M US drivers each traveling 4000 miles of interstate per year (rough estimates) we save about 5000 70-year lifetimes of wasted time per year. I don't think the speed opponents want to open this can of worms.
26.Study of Alabama roadways reported "a significant increase in the severity [of crashes] on the 65 mph interstate roadways when compared to the interstates which remained at 55 mph." The Safety Impact of the 65 MPH Speed Limit: A Case Study Using Alabama Accident Records, Brown, et al., DOT-HS-807 425 (Apr., 1989).
One more study that covered only one state. And don't you wonder about how scientific the Alabama Troopers' assessment of "severity" really is?
27.Increased speed limits increases the risk of crashes involving drunk drivers. Higher speed limits resulted in a 30% increase in the number of fatally injured intoxicated drivers. Effects On Drunk Driving Deaths of Raising the Speed Limit To 65 MPH, Hingson, et al., American Public Health Association 116th Annual Meeting (Nov., 1988).
They're not saying "speed kills" anymore, they're saying "speed kills drunks"! Are they expecting the drink drivers to write their represenatives asking for low limits so they don't kill themselves?

Ben Langlotz
National Motorists Association, Oregon Chapter Coordinator

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