Confessions of a Recovering Engineer. Charles L. Marohn, Jr.

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Название Confessions of a Recovering Engineer
Автор произведения Charles L. Marohn, Jr.
Жанр Зарубежная деловая литература
Серия
Издательство Зарубежная деловая литература
Год выпуска 0
isbn 9781119699255



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even human values. They are values unique to a profession that has been empowered with reshaping an entire continent around a new, experimental idea of how to build human habitat.

      Let us identify those values.

      When an engineer sits down to design a street, they begin the process with the design speed. I have been in countless meetings where engineers presented technical design sheets and even in-depth studies for a street project. Never, and I mean never, was any elected official or any member of the public asked to weigh in on the design speed.

      Never once did I hear one of my fellow professional engineers say, “So, what are you trying to accomplish with this street in terms of speed?”

      No. The design speed is solely the purview of the engineering professional, with a preference for accommodating higher speeds over lower.

      Why?

      These are policy decisions, and like all policy decisions, they should be decided by some duly elected or appointed collection of public officials. In a democratic system of representative government, representatives of the people should be provided the full range of options and be allowed to weigh them against each other. That rarely happens, and I have never heard of an instance where it has happened for a local street.

      Many of my engineering colleagues will reply that they do not control the speed at which people drive — that travel speed is ultimately an enforcement issue. Such an assertion should be professional malpractice. It selectively denies both what engineers know and how they act on that knowledge.

      For example, professional engineers understand how to design for high speeds. When building a high-speed roadway, the engineer will design wider lanes, more sweeping curves, wider recovery areas, and broader clear zones than they will on lower-speed roadways. There is a clear design objective — high speed — and a professional understanding of how to achieve it safely.

      There is rarely any acknowledgment of the opposite capability, however: that slow traffic speeds can be obtained by narrowing lanes, creating tighter curves, and reducing or eliminating clear zones. High speeds are a design issue, but low speeds are an enforcement issue. That is incoherent, but it is consistent with an underlying set of values that prefer higher speeds.

      Once the engineer has chosen a design speed, they then determine the volume of traffic they will accommodate. How many motor vehicles will this street be designed to handle? This is the second step of the design process, and the second instance where the design professional independently makes a decision that is, at its heart, a value decision.

      Standard practice is to design the street to handle all of the traffic that routinely uses it at present, plus any increase in traffic that is anticipated in the future. There is no consideration given as to whether that is too much traffic for the street, and rarely is there a conversation of whether other alternatives should be considered. If traffic is present, it is the traffic engineer's calling to accommodate it. No nonprofessional is given an opportunity to suggest otherwise.

      The final step of the design process then is to take the “safe” design and determine how much it will cost. This dollar amount is the price for a responsible street design. Any questioning of this minimum effort would be considered a reckless endangerment of human life.

      Now we have the traffic engineering profession's values as expressed in the design process. In order of importance, those values are traffic speed, traffic volume, safety, and cost.

      I ask them to think about a street where they live, or one where they shop or like to go out to eat. I then ask them to shout out, in unison, which value they consider most important as applied to that street. The answer, overwhelmingly, is safety.

      And of course, it is. Most humans, including most traffic engineers when they stop to consider what is being asked, would sacrifice much of the street's performance in terms of speed or volume in order to make it safer. Safety is the top value nearly all people apply to street design.

      As we continue, I ask for them to shout out their second most important value. Again, there is no real ambiguity. Nearly everyone chooses “cost.”

Current Practice Most Humans
Design Speed Safety
Traffic Volume Cost
Safety Traffic Volume
Cost Design Speed

      * In order of priority, highest priority first.

      The values of the design process — the values applied to street design —are not values that most people would identify with. I would assert that this includes most traffic engineers, which suggests that design professionals are not morally deficient people but simply that they have accepted these underlying values without debate, internal or otherwise.

      State Street was designed using a process that values speed and volume above safety.