Traffic inefficiencies and technological change

Friday, September 30, 2016
by Scott Campbell

Technology is often linked to efficiency. As in, technology change or technological progress equals greater efficiency. In our courses we try to break students of that assumption, and consider cases where greater efficiency may be harmful or anti-progressive. One of our favourites is Jevon's Paradox, in which an improvement in efficiency can paradoxically lead to an increase in consumption of the resource.

But here's another example. In this case, traffic efficiency was reduced to make streets safer.

Rowena Avenue in Silver Lake was placed on a "road diet" in 2013, where the street was reduced to one lane of traffic in each direction to make space for bike lanes and to slow down cars. It definitely had its detractors, but a op-ed penned today by a pair of data scientists argues the road diet achieved its goal of making the street less hazardous for everyone.

Although we might assume that making automobile traffic flow more efficiently (ie: faster) through a city is a good sign of progress, in this case a different type of progress was chosen: saving lives.

The decision to implement a "road diet" came about after a child walking on the road was killed by a car. Reducing the speed of traffic on the road would reduce the probabilty of further fatalities: "According to the American Automobile Association, the average risk of death for a pedestrian reaches 10% at an impact speed of 23 mph, 50% at 42 mph and 90% at 58 mph." Without really getting into whether reduced speed would reduce the likelihood of accidents, at least if one happened, the risk of death would be reduced.

And so, the street was put on a diet, and rebuilt with two lanes instead of four, and new bike lanes. Average speed decreased from 39mph to 35mph, and collisions and fatalities have decreased as well. The data also seem to show that the traffic volume remained the same, possibly countering the argument that drivers in a hurry will simply find a speedier cut-through detour on side streets. Fewer collisions, no observable impact on volume? That sounds like progress, even if it's less "efficient" in terms of speed.

It might also be described as an improvement in equal rights. An article by Sarah Schindler in the Yale Law Journal last year about architectural exclusion cited Nicholas Blomley, who described this problem as traffic logic: "the idea that planners and civil engineers prioritize the flow of pedestrians and traffic through a physical space, with a focus on civil engineering, rather than prioritizing equal access to a physical space for all, with a focus on civil rights." 

In short, let this just be a reminder that efficiency is a just choice we can make with technological changes, not an assumption; other choices are possible.