July 7, 2026
This book discusses the obligations and priorities of traffic engineers in the United States, as perceived by themselves. The main contention of the book is that most road designers view their obligation as being to maximize traffic-flow without consideration of safety.
The majority of the book is composed of quotes and statistics suggesting that a) road designers don’t value safety in road design, and b) various safety-oriented design changes can have the effect of increased safety or reduced damage.
As a reader, I find myself able to accept most, or all of the claims that the author spends a lot of time on. However, the most interesting part for me was how little effort the author commits to examining the effect of traffic law enforcement/how actively opposed the author is to even considering this path. It’s been a while since I read the book, but from my memory, there’s only one sentence about the effect of enforcement and it amounts to stating that enforcement isn’t needed because it’s a form of racism.
It’s interesting to see how the author is clearly aware that (at least some) road designers actively refuse to think about safety as being part of ‘the solution’, and he doesn’t go easy on them: professionals have an obligation, in the author’s view, to take a scientific and objective approach towards their field. Yet here he is, clearly refusing to even consider an important safety mechanism.
My main reason for reading this book was to understand why traffic-policy advisors tend towards the point of view that traffic enforcement is racist or otherwise socially detrimental; the lack of effort put into the question of enforcement and the broad dismissal left me disappointed with this book. However, I will concede that in many cases, the author makes an entirely valid point that road/intersection designers have produced incompetent designs from a safety perspective.
The author isn’t overly prescriptive in terms of exact road geometry or specific recommandations. Are we talking about adding some cross-walks in busy areas near a school? Or are we talking about “traffic-calming measures” that significantly reduce visibility? There are trade-offs across the mechanisms that road designers might employ to make a road safer, and the interplay between traffic-calming designs and human behavior needs to be considered.
In my own life, I’ve seen increased adoption of traffic-calming measures in my own neighborhood and city. It may have been true that in the 90s, or earlier, most road designers didn’t treat safety as a priority. However, I suspect this has changed in the last 15 years. I’m now concerned that traffic-calming measures are being applied without a detailed analysis of how they work in reality.
In practice, what I’ve seen is that when traffic-calming measures are installed, a certain fraction of the population will react in the opposite of the desired way: for example, they will speed through a neighborhood with significant visual obstruction, or cut off a driver in another lane when their own lane ends (because of a traffic-calming curb projecting into the road, for example). I would suggest this is an enforcement rule, but this becomes a problem if the municipal policy is to avoid enforcement for ideological reasons.
The idea that you can ‘install safety’ in a system is (in my opinion) a dangerous idea, because it convinces users that the system should keep them safe independently of their own actions. Designers should want to design safe systems, but putting 100% of the responsibility on the designer and 0% on the user is a very strange direction. Think about any other human domain; think about what kind of legal or social structure would be necessary to entirely prevent people from causing damage to themselves or others. We can put some responsibility on designers, but we can’t put 100% of responsibility on them.
I think there are three separate risks introduced by the idea of treating road designers as 100% responsible for safety while excluding enforcement as a mechanism:
The author makes a good case for safety as a priority, but I think the book would be better if it could admit the possibility of over-reach in its own thesis. No system should be optimized for just one thing, and defense-in-depth is probably the best approach for minimizing traffic fatalities while keeping things moving.