The knot driver

Northern Baltimore's I-95/695 highway interchange is a "topological masterpiece," and its superb "mathematical aesthetics" might just save it from being destroyed.

[Image: “I was in a web of braided highways." New Scientist].

"In the spring issue of The Mathematical Intelligencer, Michael Kleber, a topologist at MIT, waxed enthusiastic about [the interchange's] 'non-trivial braiding': while it is possible to just lift I-95 up and away from I-695, the northbound lane of I-95 braids both over, and then under, the southbound lane, making it impossible to pull them apart without cutting one of the lanes."

However, those simultaneous right/left exits don't seem to be helping with traffic flow, and the system's moving circular symmetry may soon be traded-in for something far simpler.
"I don't want to encourage more cars onto the roads," the New Scientist writes, "but if topology and beauty mean anything to you, get out there and enjoy I-95/695 now. It may soon be too late."

This leads me to wonder, of course, if you could take-over the U.S. Department of Transportation, and rebuild the nation's highway infrastructure as a massive textbook in driveable knot theory.
Seattle to Chicago, you drive achiral knots; Los Angeles to Phoenix, trefoils; New York to Miami, Brunnian links; while the most complicated ones are saved for a private highway system built between Washington DC and Denver.
All the tunnels of Manhattan, recurved and cross-torqued through themselves, with some so maddening only postgraduate researchers can find their way out of the city.
A new Olympic sport: driving the New York knots.

(Earlier: BLDGBLOG's Wormholes).