Pedestrian and Bicyclist Fatalities Up? More data flaws!

California Walks tweeted an LA Times articles entitled Highway deaths at lowest level since 1949; bike, truck fatalities rise. The misinformation and misunderstanding in the article includes:

The article misses that the Traffic Safety Fact: 2011 Motor Vehicle Crashes: Overview (TSF), linked from the National Highway Traffic Safety Administration (NHTSA) press release, also shows that the injury rate per vehicle mile traveled (VMT) has been flat for three years. What does this mean? It probably means that the number of crashes has not declined, just the likelihood of fatality in a crash. The rate per VMT is the only useful measure of traffic safety. Fatality counts and injury counts are a mis-measure because they are affected by the rate of driving and a number of other factors, rather than the safety of driving.

The TSF provides counts of pedestrian fatalities, up 3%, and bicyclists (the NHTSA uses the obscure term pedalcyclists), up 8.7%. To go with the counting game, this is an increase of 130 dead pedestrians and 54 dead bicyclists in just one year. No statistics are presented on the fatality rate per bicycle mile traveled. Why? I believe that it is because NHTSA is too lazy or too disinterested to compile information on bicycle miles traveled. Though pedestrian miles traveled would be difficult to compile, at least a rate could be developed per pedestrian trip, which would be a more accurate measure of the rate of fatalities. Again, the NHTSA can’t be bothered. I am certainly not the first to point out that pedestrian and bicyclist fatality counts are a mis-measure of safety, yet the federal, state, and local governments continue to ignore the issue.

The articles stated: “Fatalities are more of an urban phenomenon,” said Ted Rogers, who writes the blog.” I did not find such a quote in the blog in the last six months, but there is a blog post from October 2012 in which Rogers cautions against using statistics without context, as was done in an LA Times article and yet again in this article. Of course there are more fatalities in cities – there are more bicyclists there.

The LA Times article states: “The NHTSA said 70% of all bicycle-related deaths involve head injuries but that barely one-third of cyclists wear helmets.” I’m not sure where this factoid came from, but it was not in the NHTSA press release or traffic safety fact. What does it mean? Nothing! The implication, I’m sure intended, is that the 70% of bicycle-related crashes would not have been fatal, if only the bicyclist had been wearing a helmet. A helmet is not designed for collisions with motor vehicles. They are only tested up to 12 mph, and even at those low speeds, they are not 100% effective. I believe that most of these fatalities would have occurred whether the bicyclists were wearing helmets or not. In the contest between a one ton (or more) motor vehicle and a bicyclist wearing a lightweight piece of foam, the bicyclist is going to lose. Helmets may be effective in reducing head injuries for bicyclist self-falls, though even that is open to question, but they have very little to do with crashes involving motor vehicles. This is just more of the “blame the bicyclist” view of roadway safety.

So, take articles like these with a large grain of salt!

Noticed later: the Fast Lane blog post, which doesn’t even mention bicyclists and pedestrians, and BikePortland’s blog entry, and Streetsblog. I’m sure there will be a lot more.

8 thoughts on “Pedestrian and Bicyclist Fatalities Up? More data flaws!

  1. The comment the Times quoted from me came from a phone interview this morning after these statistics were released. And like most interviews in which the interviewer selects one or two comments to highlight out of a several minute conversation, the quote is almost inevitably taken out of context.

    The point I was trying to make was virtually identical to the comment you made. The writer asked if the total number of bicycling fatalities sounded accurate to me, given that we’ve had at least 70 cycling fatalities in Southern California in the each of the last two years alone.

    My response was that more populated areas naturally have more fatalities as they have more cyclists and more collisions; many less populated states only suffer a relative handful of bicycling deaths each year. I also stressed that the number of SoCal bicycling deaths cited above came from my own stats compiled from news and police reports, and includes fatalities from all bike-related causes, other than shootings, and so many include more deaths than the FARS data, which may or may not be limited to deaths resulting from collisions; unfortunately, that disclaimer did not make it into the article.

    As for the number of bike miles traveled, that is the holy grail of bike advocacy. However, I know of no way to provide an accurate estimate; any figure given would be a wild guess, as no one even knows for sure how many bicyclists there are in the U.S., let alone how many miles they ride.

    And given that both the writer for the Times and I are relatively high-mileage cyclists — and no, that’s not included in the article — I don’t think there was any anti-bike or pro-helmet agenda; he was simply reporting the facts as stated by the NHTSA, as I likely will when I get around to writing about it.

    While I can’t speak for Hirsch, I have often made exactly the same argument you make about the limitations of bike helmets. I credit mine for saving my intellect, if not my life, in a solo fall that left me seriously injured a few years back. But as you note, they offer little or no benefit in collisions with motor vehicles, particularly at speed.


  2. Thank you for your thoughtful response. I like your term “the holy grail of bike advocacy.” If the transportation agencies thought it was important, they’d spend effort and money on acquiring the information. In my area, the bike counts are done by the advocacy organization (SABA), not by the transportation agencies. Of course the counts are only a proxy for bicycle miles traveled, but better than nothing, which is what the agencies are doing. At least counts allow us to make a very rough rate calculation.


  3. OF COURSE the safety provided by helmets is not absolute. Your statement that helmets offer “little or no benefit in collisions with motor vehicles” is flat-out wrong.

    Your clever logic is garbage. Wearing your helmet seriously reduces your likelihood of receiving a serious head injury, which is the most common cause of death in these accidents. So wear your helmet.

    This is assinine and irresponsible logic. Think this over again.


  4. Hmm. This has turned into yet another helmet war. The main topic of my post was the increase in bicyclist and pedestrian fatality counts, and what it might mean given that we have little information about the rate because we have little information about exposure, measured in miles or trips.


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