Traffic Safety by Leonard Evans

This book is more-or-less a textbook, here is the description from amazon

Traffic Safety applies the methods of science to better understand one of the world’s most pressing public health problems. More than a million people are killed annually in traffic worldwide. This 2004 book is even better than the author’s 1991 classic Traffic Safety and the Driver. The present book covers many safety policy topics. “Traffic Safety” goes to the heart of the problem, with unconstrained analyses of the inadequacies of government in one of its chief responsibilities – to protect life. A dramatic development since the earlier book is that the United States has fallen far behind other countries in traffic safety. Prior to the mid 1960s, the US had the world’s safest traffic. By 2002 it had dropped from first to sixteenth place in deaths per registered vehicle, and from first to tenth place in deaths for the same distance of travel. Over 200,000 more Americans were killed in traffic than would have died if the US had matched the safety progress in such better performing countries as Britain, Canada, or Australia. This topic is treated in detail, and explanations are offered for the ongoing US failure.

Leonard Evans has published dozens (maybe hundreds) of traffic-safety related articles, most/many of them related to human factors. Recently:

Am J Public Health. 2014 Aug;104(8):1501-7. doi: 10.2105/AJPH.2014.301922. Epub 2014 Jun 12.
Traffic fatality reductions: United States compared with 25 other countries. Evans L.

The paper defines a new measure for traffic safety, which makes it easy to compare across different countries. He observes that traffic fatalities always peak then fall — the new measure uses only the time past the peak as a dimensionless comparison. The US peaked in 1972 at 54,589. By 2011 the US had reduced to only 60% (i.e. a 40% reduction) of the peak, which sounds good on the surface; but lags far behind other similarly situated countries, e.g. Canada has fallen to only 30% (a 70% reduction!) of their peak, Great Britain to under 25%, the Netherlands to below 20% (an 80% reduction!).

He (continues to) argue convincingly that there has been a dramatic failure in United States’ policy response — dwelling on statistically insignificant problems (GM’s ignition switch, Toyota’s floor mats), while at the same time failing to institute meaninful enforcement of actual safety problems


One interesting factoid popped up in the book that I wasn’t aware of — “known” suicides are excluded from FARS, unless they include another (a non suicide) fatality. Here’s the details from the FARS Coding and Validation Manual:

Died Prior To Crash* refers to non-motor vehicle fatalities that are involved in an crash  resulting in a motor vehicle fatality; e.g., a heart attack victim, a homicide victim, a suicide or person involved in a legal intervention that is involved in an crash in which another person dies (innocent victim).

In suicide incidents, use the following criteria:

1. If the only fatality is the suicide victim and it can be ascertained that the crash was a suicide, do not code the case.
2. If other fatalities occur, code the case as appropriate. The suicide victim’s Injury Severity should be coded Died Prior to Crash if the death occurred at the time of the crash (or prior) or No Injury if the death occurred after the crash.

* This value is an unlikely occurrence and will raise an edit flag (indeed very few, looking at 2010-2013 I’m seeing a total of 3+0+4+5 of these Died Prior to Crash)

So there’s no official was to know how many “known” suicides were not coded. This is similar to, but distinct from, the problem of non-traffic crashes.


As noted on the SHRP 2 Naturalistic Driving Study (SHRP 2 NDS) website,

The United States was, for many years, the safest place to drive in the world. However, in terms of fatality rate, the United States dropped to 2nd in 1995, 9th in 2003.


America Is Now an Outlier on Driving Deaths

As time marches on, the poor showing of US traffic fatality and injury rates continues to lose ground to virtually all other countries in the developed world.

In the chart above shows safety progress over the last 25 years; movement to the left is improvement.
Columnist David Leonhardt updates figures and citing the work of Leonard Evans, among others, and writes

Over the last few decades, however, other countries have embarked on evidence-based campaigns to reduce vehicle crashes. The United States has not. The fatality rate has still fallen here, thanks partly to safer vehicles, but it’s fallen far less than anywhere else…
“The overwhelming factor is speed,” says Leonard Evans, an automotive researcher. Small differences in speed cause large differences in harm.

Other countries have vigorous enforcement, including photo enforcement. Meanwhile the Arizona legislature has outlawed all photo enforcement on the state highway system, and continues to attempt to prohibit enforcement by jurisdictions on their own local  streets, even for school zones and signals.

Proponents of speeding tend to prey on myths such as claiming Germany’s speed-limitless autobahns prove speed isn’t a problem; and similarly claim that the real problem is driving too slowly. Neither is true; the vast majority of Germany has speed limits ; including a general limit of 50 km/h (31 mph!) in built-up areas, and fyi autobahns in metro areas do have speed limits. The latter claim is usually a mis-use of Solomons U-shaped curve which relates to data collected in the 1950’s on rural highways and has been shown to not be true generally.

Netherlands (#nl)

As the Netherlands tends to be discussed a lot (well, that’s an understatement) in cycling circles, here’s a good reference for Dutch traffic fatality stats from swov including especially the chart captioned “How has the number of road deaths in the Netherlands been developing since 1950?” broken down by person/vehicle type and thru 2018:

chart: SWOV

The number of bicyclist deaths decreased somewhat from peaks in the late 60s to early 70s, however far more dramatic declines in other modes, particularly peds, but also motorcycle and vehicle declined by larger percentages. This chart doesn’t adjust for exposure. But it does tend to imply “dutch style” bike facilities, which were installed predominantly 1980 and later, are correlated to a reduction in overall traffic deaths, and may not be causative. Reduction in peak motoring speeds is quite possibly the controlling factor. Many other factors coincided, the 1970’s oil embargoes were embraced by the Dutch as an opportunity to severely limit oil, and thus motoring, consumption; unlike the US.

See e.g. “Stop de Kindermoord grew rapidly (in the 70s)”. See historical news reels from 1950s showing swarms of urban Dutch bicyclists; far more than ever appeared in any US city at any time


5 thoughts on “Traffic Safety by Leonard Evans”

  1. I believe Evans makes very good points.

    In my view, this publication is excellent and has gone largely unnoticed: Achieving Traffic Safety Goals in the United States: Lessons from Other Nations ( [Evans, L. 2004. Traffic Safety. Science Serving Society, Bloomfield Hills, Mich. is a reference]

    Some important needs, in my view, are top level resolve and research that is independent of the agencies responsible for delivery. Nearly all transportation research funding is controlled by the state DOTs and FHWA.
    Even within the US, many of the states that have performed best are the states where the Governor has taken an active interest.

    Also Europe and Australia have very much embraced photo enforcement. Or, as they are known in Sweden, safety cameras.
    Regarding bike and ped safety, I think the Netherlands approach is the most sound.

    SWOV is the Netherlands’ independent Institute for Road Safety Research.

  2. Why America’s roads are so much more dangerous than Europe’s
    Their stats echo Leonard Evan’s work comparing US to peer industrialized countries.
    The Vox article’s authors conclude it’s Largely land-use differences.
    but they do mention specifically:

    …If that’s the case, then one much-discussed phenomenon, distracted driving, is almost certainly not the main culprit behind the spike in recent deaths. Distracted driving did not start in 2014 and there is no evidence that it has increased markedly over the past two years.
    Furthermore, American drivers are no more likely to be distracted than drivers in our peer group of developed countries, and yet in those countries traffic fatality rates have been plummeting over the past 45 years — and continue to drop.

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