Are Washington's drivers really the worst?
Allstate released a report yesterday ranking metropolitan areas by frequency of car collisions. The Washington region came out dead last, spawning headlines like "DC has worst drivers in America."
It would get far less press attention to title a report "America's least collision-prone metropolitan areas," so they dub it "America's best drivers," putting the credit or blame on the quality of individual drivers, even though driving prowess is not what the analysis actually reveals.
It's easy to manipulate or simply misread statistics. Thus far, coverage has fairly unquestioningly repeated the line that the Washington area's drivers are the worst. A Dr. Gridlock post even juxtaposes this with another misleading and fairly thoroughly debunked study, the one saying our traffic is among the worst in the nation.
What's wrong with jumping from crash frequencies to conclusion that Washington area drivers are the nation's worst? It puts the blame or credit all on the drivers, rather than the road designers, licensing authorities, and police enforcing the laws. It also treats all crashes from minor fender bender to fatality the same.
Just counting collisions misses important facts
How many of these were just property damage? Minor injuries? Major or disabling injuries? Fatalities? It's important to keep in mind that in the District, the number of traffic fatalities each year can usually be counted on one hand.
Some road designs reduce severe crashes but potentially increase minor collisions. For example, many areas are finding "modern roundabouts," the small circles without signals, to be a fantastic alternative to huge intersections with multiple turn lanes or freeway-style interchanges. They move traffic more smoothly and safely, but minor collisions are more common while major ones are less so. Limbs and lives are more valuable than bumpers.
On the flip side, bad road design can contribute to collisions. Short yellow lights or poorly-coordinated signals can lead to red light running. Poor signage or markings can confuse drivers and induce sudden movements. And what about maintenance? Crumbling roads can damage cars, potentially adding to the collision tally if the person places a claim with Allstate.
What about other modes? If the methodology counts based on Allstate claims, it might undercount pedestrians or cyclists being struck who might not have insurance. That could penalize cities with good ped/bike safety practices. On the other hand, areas with more walking and bicycling can require more attention from drivers than areas with long, straight, very wide roads where nobody dares walk, and the rate of cars touching each other might be higher despite the many other benefits of these more lively places.
We also can't let Allstate's and the press's repeated usage of the word "accidents" pass by. When we have thoroughly vetted users traveling on context-sensitive travelways being taken aback by sheer acts of God, then these can be genuinely called "accidents." Until then we have crashes, collisions, and oft-unintended unions of flesh and metal.
Maryland actually has the best drivers?
Rankings always seem to grab the most headlines, and this is useful data for Allstate to release. But it's always important to keep in mind that statistics are very finicky. A quick analysis (XLS) shows that the rankings vary enormously based on what gets factored in.
Allstate ranked areas based on the average time between claims per driver. If we adjust these numbers to equalize vehicle miles traveled per capita, then Maryland comes out with the fewest collisions. So this story could easily have also borne the headline, "Maryland drivers the best in the nation." Are they the best or among the worst? We don't really know enough to say.
What can we do?
Even though it's disputable whether the area's drivers are really the worst, most people aren't contesting or doubting it. Rather, they're nodding in agreement and cheering it on among the blogosphere. We seem to agree that we're lousy drivers.
So perhaps we don't even need thrown-together numbers to tell us that? If we just assume our region is full of bad drivers, what's next?
We could look at licensing regulations, and do more to ensure those who get or keep licenses have a decent competency to drive. However, any weeding-out is politically difficult. What if we were the ones being weeded out? In one study, the vast majority of drivers said they thought they were above average. That's statistically impossible if there's anything close to a normal distribution.
What about enforcement? We could detect and punish more of the particularly unsafe behaviors on our roadways. Automated traffic cameras are an effective solution, but they too encounter resistance. Plus, as with the roundabouts, cameras might actually make a region's Allstate ranking worse while saving lives. Statistics on red light cameras also show that they often lead to more minor low-speed rear-end collisions while reducing the much more dangerous side-impact crashes.
Finally, we can design roads for the safety of all users, motorized and not. There's often pressure to design for higher speeds and then jurisdictions set lower speed limits when people get hurt. We can do more to build in the visual cues that help people slow down, pay attention, and reduce crashes, or at least reduce the most severe ones.
Any of these take some political courage. Will our region's leaders stand up to take action to improve DC's ranking on this survey or, better yet, on the more important statistics of fatalities and severe injuries?
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