LONGER-term Effects of Repealing the National Maximum Speed Limit in the United States

Some legislators have squelched bills for higher speed limits, citing research published in 2009 by Lee S. Friedman, PhD; Donald Hedeker, PhD; Elihu D. Richter, MD, MPH.

The research is entitled “Long-term Effects of Repealing the National Maximum Speed Limit in the United States”. http://www.medscape.com/viewarticle/715218

The facts are simple: National Speed Prohibition was repealed effective November 28, 1995. In 1995, interstates had 4,836 deaths while US traffic deaths overall totaled 41,798.

By 2005, interstate deaths had climbed 21% to 5,874; while US traffic deaths were up 3% to 43,443.

Motivation enough for publication!


By 2011, interstate traffic deaths had dropped to 4,112; total traffic deaths plunged to 32,367. Those figures are 15% and 25% lower than the counts in 1995, respectively. Compared to the peak 2005 figures — 30% and 23% lower respectively.

I’ve not even bothered accounting for increased travel, different speed limits (65, 70, 75), etc.

So was the 25% increase in interstate fatalities through 2005 due to higher speeds? Or was the subsequent 30% decrease through 2011 due to higher speeds?

Correlation isn’t causation; perhaps there’s no correlation with speed at all.

I imagine we’ll never see a follow-up study by Drs Friedman, Hedeker and Richter, eh?





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‘Excessive speed’ is just a politically correct label for when the police are uncertain what caused the accident

My April 22, 1996 “letter to the editor” in the Dayton Daily News was given the title shown  above by the newspaper editor. My lettter reads as follows:

I’m quite pleased that Interstate 675 will be getting 65-mph limits posted by June 28th. As the only citizen who traveled to Columbus and testified in favor of 65-mph limits in 1987, 1990, 1992, and again this year, I think I have reason to be pleased.

Actually, this was started by a speeding ticket issued to me on I-675 just north of U.S. 35 back in 1986 [then-like everywhere in Ohio, posted at 55-mph]. When the patrolman handed me the ticket, his standard lecture had just gotten to the part about “half of all accidents being caused by speeding.” “Stop,” I said to him. When police issue a so-called speeding ticket after an accident, it’s for “speed excessive for conditions.” The key word is “conditions,” such as rain or curves in the roadway. My reply to him continued: “Excessive speed” is just a politically-correct label for when the police are uncertain what caused the accident. “So,” I pointed out to him, “what you’ve just admitted is that half the time, Ohio’s Finest don’t know what caused the accident.”

As he started to sputter, I took the ticket and left. At that point, I decided I would volunteer my spare time to be Ohio coordinator for the National Motorists Association.

As a professional engineer, I know decades of research show no linkage between travel speeds and accidents per travel-mile. Traffic safety is far too complex to be sloganized into “speed kills” — unless you benefit from writing speeding tickets. The logical conclusion of “speed kills” is a return to Ohio’s speed limits of 1913, that is, 20-mph in rural areas.

However, decades of traffic engineering research show that most people are reasonable and prudent. The actions of the prudent majority should be legal, so the speed limit on I-675 should be at least 70-mph.

But 65-mph will be improvement enough for this year.

NOTE: Sourced from the webarchive version of my prior website

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Speed Investigation of Ohio Route 835 in the City of Beavercreek 1992-1993

NOTE: sourced from webarchive version of my prior website

by Duke P. Ganote, P.E.
May 27, 1993

As I discussed in the newsletter first posted in this topic, the posted speed limit on Ohio 35 is now 50-mph [it was originally posted 35-mph].

Using a radar gun, I collected five samples of “before” speed data, and 3 samples of “after.” The “before” and “after” data is presented next.

Conclusion: speeds may have increased 1- or 2-mph since the posted limit was changed from 35-mph to 50-mph. Most of the increase seems to be due to slower drivers getting “up to speed” and “into the pace” (the percentage of drivers in the pace is up from about 60% to about 70%).

[I] took eight (8) bidirectional spot speed samples of 200 vehicles each on the mainline section of SR 835. Samples were taken under favorable conditions: dry pavement, temperature from mid-50s to 70s (F), overcast to sunny weather, and no permanent enforcement presence. Summary data is shown below.

_______________  ______________ ________
 90th%tile (mph) 57 55 58 55 56 57 56 58
 85th%tile (mph) 55 54 55 54 54 56 55 56
 67th%tile (mph) 52 50 51 50 49 53 52 53
 50th%tile (mph) 49 48 49 47 48 49 50 51
 15th%tile (mph) 43 43 42 42 42 45 44 46

PARAMETER      BEFORE [1]               AFTER [2]
______________ ________________________ ______________
Pace [3] (mph) 53.0 53.0 52.5 52.0 53.0 54.0 56.5 55.0
     % in Pace 57.5 66.0 59.0 63.5 63.0 67.0 70.5 71.0
Mean (mph)     49.3 48.3 48.9 47.8 48.0 50.1 50.4 51.0

PARAMETER         BEFORE [1]               AFTER [2]
_________________ ________________________ ______________________

% exceeding 65mph   1.5   0.5   1.0   1.0   1.5   1.0   0.5   2.0 
% exceeding 60mph   5.5   2.5   5.0   2.5   3.0   4.0   3.0   6.0 
% exceeding 55mph  15.0   8.5  12.5   9.5  13.0  15.5  14.0  15.5 
% exceeding 50mph  43.0  31.0  36.5  27.5  28.5  44.0  46.0  50.5 
% exceeding 45mph  68.5  66.0  66.5  62.0  62.5  81.0  81.5  86.5 
% exceeding 40mph  94.0  91.0  92.0  88.5  88.0  95.5  97.0  99.0 
% exceeding 35mph 100.0 100.0  99.5  98.5  99.0  99.0 100.  100.

[1] April 22, May 3 & 16, June 10 & 20, 1992
[2] May 9, 13 & 27, 1993
[3] Upper limit of 10-mph pace (10-mph grouping with largest number of vehicles)
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85 MPH in Texas

WONDERFUL idea in Texas — and elsewhere! Safety features like wide medians and overpasses give rural interstates an impressive safety record. For example, Texas’ interstate fatality rate of 1.25 was better than all other Texas rural roads, which had rates up to 4.95 deaths per 100 million travel miles in 2009.

Unsurprisingly, the safety situation is comparable in Germany — even though Germany is the “crossroads of Europe” — even though relatively-untrained American drivers stationed in Germany do well — even though Germany has transitioned the former East Germany’s Soviet-style speed zoning and enforcement into Western standards.

Hand-wringing and radargun-slinging DON’T improve traffic safety. Read it for yourself: http://www.fhwa.dot.gov/policyinformation/statistics/2009/fi30.cfm

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To Serve The Public

The government’s goal: “to Serve the Public”…Served Roasted over a Open Flame for their Own Benefit, that is.  “Despite N.J. OK, 3 red-light camera intersections don’t comply

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Hand-Wringing and Radargun-Slinging Doesn’t Improve Traffic Safety.

That was my concluding statement on the ABC News article about Texas’ proposed 85mph speed limit:

I mention that the U.S. has fewer traffic deaths now than ever with the 55-mph speed limit?Conclusion: hand-wringing and radargun-slinging doesn’t improve traffic safety. Knowledge will.

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Fireplace or Florida

On the Newser comments,

SPHeroid said

Going faster most certainly uses more fuel…..

Wind resistance increases as the square of velocity;  Double the speed increases resistance by a factor of four….And the only way a vehicle can overcome it is with greater engine output…..

Sure, let’s look at fuel economy.  FIRST, almost all EPA new car stickers will tell you that fuel-economy on the highway is better than city driving.  So “speed” isn’t the largest factor in fuel consumption.

SECOND, consider the last study in which the Federal Government measured steady speeds and fuel consumption — the most recent vehicle had fuel economy that “was slightly better at 65 mph than at 55 mph” (Table 4.27 in the 2011 Transportation Energy Data Book (TEDB) http://cta.ornl.gov/data/tedb3… )

THIRD, consider that the “latest” study was back in 1997!  It takes little imagination to believe that improved aerodynamic design, lighter materials, etc has improved fuel economy since then.

FOURTH, consider my 750 mile spring break trip to Florida.  Hypothesize that 70mph vs 55mph decreased my Honda Fit’s economy from 35mpg to 30mpg (that’s the 17% average decrease in Table 4.26 of the TEDB).  Each way, my trip consumed 25 gallons instead of 21 gallons.  4 gallons x $4 = $16. I chose to spend the extra $16 to spend an extra couple of hours on the beach instead of the road on the way down.  That’s a common travel choice — the cost of fuel can considerably higher in Europe ($8/gallon), yet average speeds are still quite high.

Basic economic reality nudged the National Academy of Sciences back in 1984 to concede that the 55mph religion wasn’t all benefits and salvation of mankind, and that maybe…just maybe… higher speeds on rural interstates were not unreasonable.

Look I’m not bent on an argument  with you….
Point one ….duh…. Higher gear ratio, no stops…
In addressing  your second point, this would only be true if the transmission has a large over-drive gear….
But the engine still has to overcome the air resistance, internal friction, and road resistance…..

I won’t touch number tree….As you pointed out it’s a fail….

And fourth, This is the kicker; Do you want to save time or money?…I guess you’ve made your choice…..

RE: “the kicker; Do you want to save time or money?”

It’s the same choice most people make.  If money was everything, Ebenezer Scrooge, then the Cratchit family would stay home by the fireplace.



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