Killed by a Traffic Engineer

Annotated Table of Contents

Killed by a Traffic Engineer

Shattering the Delusion that Science Underlies our Transportation System

By Wes Marshall, PhD, PE

General Overview:

For at least the first 1,000 years since Hippocrates, it wouldn't be hard to make a case that doctors killed more people than they saved. Traffic engineering is only 100 years old, and traffic engineers still kill more people than they save.

This isn’t necessarily the fault of today’s traffic engineers. They look at their thousand-page manuals and understandably think that the science behind traffic engineering is mostly settled.

Unfortunately, the science is far from settled. Much of what traffic engineers do today was built on a rickety foundation of pseudo-scientific theories that prioritize speed, capacity, and driving over actual safety outcomes. Killed by a Traffic Engineer exposes the unscientific origin stories behind current standard practice and then sets forth a plan to fundamentally change the stateof-the-practice… and start to save lives.

Killed by a Traffic Engineer is comprised of 88 short chapters organized into a dozen parts. The following overviews the 12 book sections:

Part 1: What Are We Doing Here?

Killed by a Traffic Engineer starts off with stories that highlight the scale of the road safety problem, why so few people care, and why our historic focus on interventions such as Enforcement and Education are short-sighted and ineffective. It includes a chapter on “engineer speak” that lets the reader peak behind the curtain of the words that traffic engineers use when they want to shut the public up and continue with business as usual.

Part 2: Mismeasuring Safety

It’s standard practice for traffic engineers to measure road safety outcomes in terms of how much we all drive. So instead of finding better safety with fewer crashes, injuries, and deaths, we can seemingly achieve better safety by simply driving more. Killed by a Traffic Engineer dives

into the history of this convention – under the umbrella of how traffic engineers characteristically focus on the wrong goals and measures – and the implications of it when it comes building better places and improving real safety.

Part 3: Make No Mistake

Traffic engineers routinely state that at least 94% of crashes can be blamed on human error. Traffic engineers also believe that nobody would die on our streets if only everybody followed the rules laid out for them. This faulty premise lets traffic engineers off the hook and keeps us from fixing the underlying problems… or even from realizing that there is a problem in the first place.

Part 4: I Feel the Need for Speed

Speed is one of the core design criteria in traffic engineering. Yet, traffic engineers have long ignored the fundamental physics by focusing on faulty studies suggesting that high speeds are safer than low speeds. Killed by a Traffic Engineer highlights why speed is misused in standard practice and why supposed human error problems like speeding need to be treated as an Engineering issue more so than an Enforcement one.

Part 5: Designing Time

Street design is one of the key jobs of a traffic engineer, but Killed by a Traffic Engineer shows that the streets with the most traffic engineering give us the worst safety outcomes. While Killed by a Traffic Engineer covers the typical complaints, such as those streets being too wide, the focus is more on why this happens. In terms of wide streets, the underlying problem has to do with the traffic engineering procedural focus on capacity and, more specifically, on capacity 20 or 30 years into the future.

Part 6: A Bird’s Eye View

Transportation design – and safety outcomes – is more than a street or intersection design issue. It’s also about street network design and land use. Traffic engineers ignored these connections, misinterpreted the safety data, and systematically went about shoving limited-access freeways through the low-income and minority neighborhoods of our cities. The traffic engineering standard approach to community building led to much more driving and many more deaths, but given how we measure safety, seemingly better safety outcomes.

Part 7: Ok Data, Don’t Mess This One Up

Everyone wants a data-driven approach to safety, but what if the data is flawed? How can traffic engineers make data-driven decisions with incomplete and biased crash data that focuses on cars while treating pedestrians and bicyclists as second-class citizens? How can traffic

engineers learn anything about what systemic Engineering issues led to why these road users did what they did when the data is collected only to figure out which road user is at fault?

Part 8: The Blame Game

The traffic engineering boogeyman is liability. Most traffic engineers protect themselves by blindly following the standards, no matter what the empirical evidence says. Killed by a Traffic Engineer shows that the persistence of this mentality is a liability issue in itself and how a simple, rational approach will give traffic engineers the freedom they think they lack.

Part 9: Standard Issue

Any young traffic engineer – as well as most seasoned veterans – believes that whoever wrote our 1,000-page manuals must know more than they do. But those who wrote the so-called Bibles of traffic engineering readily admitted that they didn’t know that much back when our so-called standards came to be.

Part 10: Safety Edumacation

Traffic engineering gets accused of having a silo problem, but our universities barely teach undergraduate Civil Engineers anything about traffic engineering. Many licensed professional traffic engineers have never even taken a single transportation course. Grad school might help the cause, but few programs offer courses specific to road safety, let alone ones that prioritize pedestrian and bicyclist safety.

Part 11: Spark Joy

So how do we fix all these safety problems? Killed by a Traffic Engineer lays out a vision that reinvents the discipline by completely shifting our focus from our current Whac-A- Mole reactive approach to a proactive one focused on fundamental categories.

Part 12: What Matters and What Next?

Traffic engineers like to show statistics claiming that our streets are safer than they’ve ever been. Mission accomplished they say! Killed by a Traffic Engineer instead shows why we vastly underestimate our road safety problems before ending with a call to action.