• Dave

Shoeleather engineering

Transportation and health has recently become a hot topic in transportation. Much of the focus has been on the relationship between and it’s influence on the environment, physical activity, and safety. As someone trained in civil engineering and public health, this is a welcome development. However, Civil engineers are some of the most effective public health professionals. The link between civil engineering and public health goes all the way back to the origins of public health as a field. It's time civil engineers act like the public health professionals that we always have been.

The founding narrative of public health is that of John Snow and the Broad Street pump.

The real John Snow. He knew something.

Most epidemiologists will recognize the story. A cholera outbreak was tearing through London in 1854. The miasma theory of disease, which states that ailments were caused by “miasmas” of bad air, dominated medical thinking at the time. Germ theory hadn’t been developed. Since people did not realize that microscopic organisms were infecting their water supply, they had no reason to believe that this was the source of the outbreak. Snow famously objected to the miasma theory and identified the source of the outbreak as a water pump on Broad Street in SoHo. Snow discovered this by speaking with local residents, identifying cases of cholera, and mapping where residents drew water and where cases occurred (notably brewers nearby only consumed their product rather than water and none died).

His maps suggested that the Broad Street pump was the source and he had the handle removed. The outbreak promptly ended, although it was likely slowing down before then.

One of John Snow's original maps of a cholera outbreak. Shoeleather epidemiology at its finest.

Snow’s discovery went largely unappreciated for many years, but shortly after his study,

Bazalgette built the Victoria Embankment during this project. It's now outfitted with speed limiting measures on top and an underground station below. Photo © PAUL FARMER (cc-by-sa/2.0)

London’s infamous “Great Stink” struck the city in the summer of 1858. After centuries of dumping waste into the Thames, the summer heat caused putrid smells to waft into the city. Local and national leaders finally took notice and charged Joseph Bazalgette to redesign London’s sewers. He thus began a nearly 20-year project. John Snow died in 1859 without ever seeing the system completed, or realizing that his work would create an entire field of study. The impetus for this project was to remove the stench and waste from the Royal River, but would go on to save untold numbers of lives and established sanitation as a public health intervention.

Many other engineering achievements have resulted in public health improvements, from latrines to paved streets to storm surge barriers. Civil engineers, whether they realize it or not, are front-line public health workers, and it’s time to start acting like it. We have a duty to build infrastructure that not only does no harm, but actively improves health.


There are two things that transportation engineers can do to fill their role as public health practitioners: proactively eliminate risk, and do some shoeleather engineering.

Public health professionals attempt to remove as much risk as possible before you become sick. Water is filtered and managed to remove pathogens. You take vaccines to protect you from the flu or measles. Transportation engineers can remove risk factors by separating road users in terms of speed in both time and space. We need to think about risk and how to remove it systematically as a primary objective.

Shoeleather epidemiology harkens back to John Snow going door-to-door to identify cholera cases and their sources. Epidemiologist take pride in wearing out their shoe leather to identify problems. It’s a sort of badge of honor when you can say that you’ve been out in the field and worn out your shoeleather tracking down a disease. Shoeleather engineering needs to become commonplace for transportation engineers. We need to get out there, talk to people, and just plain watch traffic. The public engagement process is broken. Rather than holding countless public meetings, go out to the area you are working on and talk to the neighbors. They’ll be thrilled to hear that something is going on to improve their neighborhood and happy to identify problems for you. Further, just watch some intersections. I’ve learned so much by simply watching traffic and seeing how people react to design. If you're a transpo engineer in Atlanta, or just transpo-curious, start wearing out that shoeleather. I'd be happy to join you. Think about how to remove risk rather than respond to crashes after the fact.

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