Friday, April 22, 2005

Traffic Fatalities - A National Endemic

BrooklynDodger vacillated on whether this was personal or scientific, and has opted to snark on the National Safety Council and DOT in the scientific arena.

First, the Dodger must complain that a condition which is more or less the same all the time is "endemic" not "epidemic." Endemic conditions likely do more damage than epidemic. This is slovenly terminology, like conflating acute [short term] with "really bad."

Second, the Dodger questions whether issuing a preliminary account, to be followed by a final account alleged to have the same data, is merely a twofer for press release purposes.

Next comes the interpretation, particularly the highlighting of the seat belt issue, and drunk driving which didn't get mentioned. The DOT report is available as a powerpoint at

For 2004, it's projected there will be 42,000 motor vehicle fatalities. Fatilities are trending down, except for motorcycles and heavy trucks, which are going up.

44% of vehicle occupants killed were wearing seatbelts. This suggests some limits in seatbelts as a total strategy. Alcohol was found in 39% of fatalities [assuming mostly the driver]. Some fraction of these alcohol related fatalities were caused by the same factors which caused the 61% unrelated. Speeding was identified in 31% of fatalities.

Preliminary efforts at parsing the FARS data base suggests confounding of drunk driving and not wearing seat belts. The high fatality times are weekend nights. Probably speeding is confounded with drunk driving and not wearing seatbelts. Younger drivers are at increased risk. Together this suggests that interventions aimed at mature drivers going to work in daylight will do little to reduce fatalities.

Among the 5100 killed in heavy truck incidents, 750+ were in the heavy truck and the other
4000 were in the light vehicle. About 16% of the total. This rate went up 4% for total victims. For trends, heavy truck is trending up, and light vehicle only incidents are trending down. Likely seat belts are less effective in crashes between light vehicles and heavy trucks.

Mineta: Highway traffic fatalities ‘national epidemic’

On April 21, Transportation Secretary Norman Y. Mineta announced “mixed results” in the effort to reduce the number of people killed on U.S. highways. Although the fatality rate dropped and alcohol-related crashes were down from 2003, 42,800 people died on the nation’s highways in 2004 – up slightly from 42,643 in 2003, according to projected 2004 data compiled by NHTSA in a preliminary report. The report also projects the seventh straight increase in motorcycle fatalities.

Mineta called the number of fatalities a “national epidemic,” and said, “If this many people were to die from any one disease in a single year, Americans would demand a vaccine. The irony is we already have the best vaccine available to reduce the death toll on our highways – safety belts.”

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