Three secrets hidden in Metro’s great new map of every local traffic collision

Three secrets hidden in Metro’s great new map of every local traffic collision

metro area collisions

Every reported traffic collision in the Metro area, 2007-2013.
(Source: Metro Crash Map)

Last spring, the City of Portland created a fantastic new map of every fatality and major injury on its records for a decade. Now, regional government Metro has followed suit with a similar map that includes many other cities and unincorporated areas, too.

It’s not just an essential tool for understanding the context of future traffic collisions. (Should we be arguing about the specific circumstances of collision X, or does something seem to be inherently wrong with the street it happened on?) It’s also a source of some useful insights about road safety in Portland.

Half of reported collisions damage only property, not people’s bodies
property damage only

Reported collisions involving any mode that damaged property but didn’t cause injury.

The sheer amount of damage we do to physical objects by banging into them while going about our business is often forgotten.

When we talk about the cost of our road system, we don’t measure this. When AAA estimates the annual costs of car ownership, this isn’t included. (In AAA’s imaginary world, every new-car dealership would be thriving and every mechanic would be broke.) But when a car hits something, you can bet that someone is going to end up paying for it, no matter how rich or poor they are and what other more useful things they’d rather do with that money.

According to Metro’s statistics (visible in the upper left of their map if you check the various boxes), 53 percent of reported traffic collisions cause only property damage, and cars were the only vehicles involved in 99.77 percent of them.

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There are lots of crashes downtown, but very few fatalities
fatalities

Traffic fatalities involving any mode, 2007-2013.

If you look only at fatalities in Metro’s map, the big downtown Portland blob disappears. Why?

The blob is there on the other maps not because downtown is dangerous, but because downtown gets lots of traffic. But if the blob vanishes for fatalities, that means that downtown is an extremely nonlethal area despite so many people coming and going.

What’s going on?

One of the less appreciated principles of Vision Zero as it was developed in Sweden is that in order to decrease fatalities and life-changing injuries, you sometimes need to increase the risk of non-fatal crashes.

That’s why things like narrowing traffic lanes, putting objects in the street and planting trees along curbs, which might have struck a 20th century traffic engineer as “dangerous,” can actually be good from a Vision Zero perspective. All of those measures make people more nervous about driving fast … so they don’t drive fast. Which is the single most important way to reduce fatalities and life-changing injuries.

Sometimes someone screws up, and sometimes they cause a collision. But if traffic is generally slower-moving, then the increased risk of a low-speed collision is a good price to pay for decreased risk of a high-speed one. At least, that’s the argument.

This map implies that if streets throughout the metro area looked more like streets in downtown Portland — short blocks, narrow lanes, ubiquitous jaywalking — we’d all be much, much safer.

Alcohol is involved in twice as many major car-car collisions as major bike-car collisions
alcohol-related fatalities and visible injuries

Alcohol-related collisions that resulted in fatalities or visible injuries, 2007-2013.

Drunkenness (by either party or by both) is a much bigger factor in car-on-car collisions that caused death or serious injury (15 percent of such collisions) than in car-bike collisions that caused death or serious injury (6.4 percent of such collisions).

This is where the phrase “vulnerable road user” comes from. Impaired judgment and reflexes are often needed to seriously injure someone inside a collapsible steel box. Not so with someone on a bike.

People are vulnerable road users while walking, too, and Metro’s stats show that alcohol is involved with fully 28 percent of major car-on-pedestrian collisions. Presumably that’s because drunk walking is so common — much more common than drunk driving or biking. And though all such fatalities are horrible and drunk walking is often a bad idea, it’s actually a great thing that drunk walking is so much more common than drunk vehicle use.

There are lots of other insights, many of them locally specific, to be gained from a project like this. Feel free to share others below.

— Michael Andersen, (503) 333-7824 – michael@bikeportland.org


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