Our blog area carried an item a few weeks back about a new engineering textbook that tries to instruct students in social justice, encouraging “engineers to think about the long and short-term implications of their projects,” as the book’s blurb puts it. The author, a professor of bioengineering, gives the example of designing an SUV for a third-world country. The responsible engineer, the author asserts, should among other things ask, “Will having SUVs make the citizens more or less able to live their lives freely?”

As you might expect, there were differing opinions about whether engineers are really in a position to determine the degree to which their work impacts factors such as a population’s ability to “live their lives freely.”

In the same vein, blog kibitzers point out that it’s not clear how most engineering projects could be judged for their social responsibility given that many inputs needed for this task are unknowable.

It turns out that concerns about such matters are nothing new. We can draw insight from discussions about another area of engineering that was controversial decades ago: public roads and where to put them. In the late 1940s and early 1950s, there was a great debate about where to route a national highway system. It was during this period that a University of Michigan economics professor named Shorey Petersen explained the fallacy of projects undertaken for the public “general interest” (which in 1950s vernacular meant social justice): It is impossible to quantify social good. So projects undertaken with that goal are often manipulated by politicians and others with an axe to grind.

“Control of road improvement through judging its relation to the general welfare is as debatable, as devoid of dependable benchmarks, as deciding the proper peacetime expenditure of national defense or the right quantity and quality of popular education,” he wrote. “Controlled in this way, highway projects are peculiarly subject to ‘pork-barrel’ political grabbing.”

Petersen’s point was that highway engineers of the day should mainly concern themselves “not with the broad matters of public interest, but with specific relations between road types and traffic conditions and with the quantities and kinds of traffic that ... will probably exist for given routes or areas.” In other words, put the roads where hard data indicated they’d do the most good, rather than where politicians claimed they should go.

If Petersen was around today, I believe he’d see elements of the public road controversy in the indistinct goals of sustainability and “green.” And I suspect he might have a problem with any engineering textbook that asks such questions about third-world SUVs as, “Will the increased congestion, pollution and dependence on fossil fuels be acceptable?”

One issue for the engineer is that these entities aren’t quantifiable in ways that can lead to an evaluation of alternatives. Unless, that is, you think you can figure out how many units of pollution third-worlders are willing to trade off against a unit of mobility in an SUV. Ditto for units of fossil-fuel dependence.

And of course, Petersen might also say the best way to further goals of sustainability and “green” is to simply deploy resources the way the numbers say is most efficient. In the long run, projects engineered this way are likely to bring more social justice than pursuit of vague objectives voiced by politicians and special interest groups.

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