Safety on the roads

CCM list post.

“Even if you were able to
convince 50% of the population to ride a bike, the other stubborn 50% of us
are just going to be more like to hit one of you since you will be all over
the place and are harder to see.”

True and false. Say that the mode split is 95% cars and 5% bikes, and that
10% crash in any given year. The odds of any given crash (indeed, any
interaction of any sort between two vehicles on the road) being between two
cars is 90.25%, between a bike and a car 4.75%, the odds being between two
bikes 0.25%. If that ratio changes to 50/50, then those percentages go to
25%, 50%, and 25%. That means that car-car crashes will fall by 72.3%
(percentage-wise), bike-car crashes will increase by 1053%, and bike-bike
crashes will increase by 10000%. The last bit is crucial, because very few
deaths occur from bike-bike crashes due to the relatively small momentum of
a light vehicle + generally lower speeds. And since mortality rates for
bicyclists *per trip* (not per passenger mile, which is misleading since
bicycle trips are shorter) is actually lower than for motorists, the nation
would see a major reduction in fatalities from transportation crashes. That
reduction pales in comparison to the lives that will be saved through
improved cardiovascular health and reduced air pollution, though.

This model is, however, ridiculous because it removes one crucial factor:
social change. In rich-country (OECD/Annex 1) cities where more than 50% of
all trips are made by walking and cycling, as in Stockholm, Copenhagen,
Freiburg, Geneva, or even Davis, California, citizens — since the majority
of citizens are walking and cycling — demand improved cycling and walking
facilities for greater safety, and often demand commensurate limits to the
speed and access granted to motorists. Bicycle lanes and paths, bollards
along sidewalks, pedestrian-only streets, speed bumps, special traffic
signals for cyclists and pedestrians — if demand for cycling and walking
facilities increases, democratic governments are quick to implement these
and other measures to improve safety for pedestrians and cyclists.

An increase in the number of bicyclists on the roads leads to improved
driver awareness of cyclists and to lower bike-car crash rates. If a driver
knows that many cars and bikes use a given street, s/he will look for both
cars and bikes before turning onto that street. This is hard to prove, since
cities with high numbers of cyclists tend to have extensive bicycle facility
networks (and any improvement in safety could be due to either human or
physical differences), but both drivers and cyclists have pointed this out.

I don’t deny that there’s a thrill to speed — sustaining 30 mph on a
straightaway is absolutely exhilirating, even more so because you know that
*you* are providing that power (not some abstract machine). However, anyone
who truly loves the power and speed of cars should be aching to get all
those other drivers off the roads. How many chances does one get to go from
0 to 60 on roads that are always congested with millions of drivers who
don’t see the beauty of speed — who are driving as drudgery, because
there’s no other way to get from A to B? Driving might be fun, but is
driving in traffic fun? Given a fixed road network, cars are a “privative
good” with a “negative marginal utility”: an increase in the number of cars
decreases the utility (say, fun) of everyone who owns a car, by increasing
traffic congestion. So, it’s in every *real* car lover’s best interest to
have fewer cars out there on the road.

Think of it like flying: some people fly airplanes purely for fun, and
because they love planes. Yet “general aviation” gets shunted out to tiny
satellite airports far away from major cities, and is restricted to a tiny
slice of airspace. The rest is given to big commercial jets that are mostly
hauling miserable people around between miserable airports. I suspect that
many of the people riding those jets, especially on shorter flights, would
rather teleport themselves, or maybe take a high-speed train from city to
city. If America eliminated 50% of the commercial air traffic from its
airspace, we could open up vast new skies for general aviators, the people
who fly planes for fun. And those folks could fly from airports closer to
home, since the jets are no longer hogging up all the low-level airspace
near the cities.

Advertisements