253: Highway Engineer Pranks

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Highway Engineer Pranks
Prank #11: Boston
Title text: Prank #11: Boston

[edit] Explanation

Some classical but inaccurate interchanges are shown. In general, these interchanges are designed to allow the traffic to flow without directly crossing any other traffic stream. But here we can see some different approaches:

  • The first design resembles a cloverleaf interchange, but has no way to merge back onto the highway once you enter it, making it inescapable.
  • The second interchange has off-ramps that you would normally use to change to the other highway, but in this design they simply merge back to the original highway, so you don't really have a choice in where to go.

In the title text Boston is mentioned, a slightly more complicated prank in itself. A common fiction is that the streets evolved from old cowpaths; but in the 17th century they avoided swamps and marshes and followed shorelines before the original peninsula comprising the city was expanded with landfill in the 19th century. Boston's road infrastructure in general lacks a street grid like most other US-cities have. On top of that, roads change names and lose and add lanes seemingly at random.

[edit] Transcript

[Each panel depicts a highway intersection.]
The Inescapable Cloverleaf:
[Roads lead onto the rings for each leaf, but then are trapped in the circles. Minor roads also allow travel between the rings.]
The Zero-Choice Interchange:
[On and off-ramps exist, but they lead back to the same lane they disconnected from.]
The Rotary Supercollider:
[The roads lead into a traffic circle, and then a loop reverses the direction of flow so all the roads run into each other.]
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The US-67 @ IH-20 interchange in Dallas has sort of a zero-choice interchange: If you're not already on the highway, attempting to get on the highway will take you beyond the interchange. It's a mess. 05:38, 14 December 2014 (UTC)

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