Physical Reality Governs

Structural engineering is pretty much the reverse of the high-tech virtual world that is hyped in the press as “technology.” Whatever computerized tools we use in design, our work is grounded, literally, in the physical world and its constraints.

This article and its linked source are fascinating in the way they reveal the lack of contact that some very successful people have with the realities of the physical world. One of the most basic of those realities is that space is limited in cities. If cars are used to transport people there needs to be (1) room for them to drive and (2) either space for them to park or road space enough for them to cruise. In theory, if cars were some kind of self-driving public utility then they could go pick up another passenger after they drop one off, but there would still need to be room to store a reserve capacity of cars for the peak periods.

So far, so sci-fi. But the details are where the problems start. What does a car that’s in use all the time look like? A taxi. Worn and public. There would seem to be a tension between using cars for transportation and telling everyone that they can’t use their own car, but rather one of the inevitably ugly and dirty public cars in order to not have to knock down everything to create parking.

Narrow-bore tunnels might seem like a way to create more driving lanes without ripping an entire city apart but (a) they are as vulnerable as any other one-lane road to severe back-ups from accidents and breakdowns and (b) they don’t provide enough capacity. A while ago I looked at traffic crossing the East River, the biggest bottleneck to free movement in New York City. There are half again as many lanes for cars as there are for trains, but using numbers tilted towards cars still shows at least three times as many people can be carried by rail. How many new tunnels would have to be created to significantly increase traffic flow?

Then of course, there are more mundane problems. Subterranean tunnels take a lot of maintenance. Creating a lot of small ones increases the maintenance bill a lot faster than in increases capacity. The centers of big cities tend to have a lot of infrastructure buried: not just existing rail and vehicular tunnels, but also utilities, old geographic features that got buried, and pieces of buildings. Tunneling through a city center is not as easy as it might seem.