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--- transportation:transportation [2024/01/15 23:15] – timb
+++ transportation:transportation [2025/08/10 22:23] (current) – [Highways] timb
@@ Line 345: / Line 345: @@
 https://www.latimes.com/california/story/2023-10-13/caltrans-whistleblower-says-demoted-block-freeway-expansion
+== Why Are Texas Interchanges Texas So Tall? ==
+August 20, 2024 - Practical Engineering
+[Note that this article is a transcript of the video embedded above.]
+This is the Dallas High Five, one of the tallest highway interchanges in the world. It gets its name from the fact that there are five different levels of roadways crossing each other in this one spot. In some ways, it’s kind of atrocious, right? It’s this enormous area of land dedicated to a complex spaghetti of concrete and steel; like the worst symbol of our car-obsessed culture. But in another way, it really is an impressive feat of engineering. 37 bridges and more than 700 columns are crammed into this one spot to keep the roughly half a million vehicles flowing in every direction each day.
+They say everything’s bigger in Texas, but that’s not always true when it comes to engineering projects in the US. The tallest concrete dam is split between Arizona and Nevada. The longest bridge span is in New York. The longest road tunnel is in Alaska, and the longest water tunnel, not only in the US but the whole world, is the Delaware Aqueduct in New York. The largest hydroelectric plant is the Grand Coulee Dam in Washington, while the largest nuclear plant is in Georgia.
+But one thing that Texas really does do bigger is highway interchanges. If you’ve driven from one major Texan highway onto or over another, you may have been astonished to find yourself and your vehicle well over a hundred feet or 30 meters above the ground. There’s no clearinghouse of data for flyover ramp heights, as far as I can find. Plus there’s the complexity of what a true height really means since many interchanges use excavation below grade for the lower level. Still, even the most conservative estimate puts the High Five taller than the Statue of Liberty from her feet to the top of her head. And if you do a little digging, you’ll find that many, if not most, of the tallest highway interchanges in the world are right here in the Lone Star State. Let’s talk about why. I’m Grady, and this is Practical Engineering.
+https://practical.engineering/blog/2024/8/19/why-are-texas-interchanges-texas-so-tall
+== WWII, the autobahn, Ike, the Interstates, and one-mile-in-five ==
+July 25, 2024 - jwh1975
+Earlier this summer I was talking with a fellow veteran and the subject of “one-mile-in-five” on the Interstate highways came up.
+The vague gist is that before WWII, Germany designed its famous autobahn network with war in mind. Near WWII’s conclusion, Gen. Eisenhower was impressed with the autobahn and during his later Presidency ordered a copy of it made, the USA’s Interstate system, mostly for military reasons including for US Air Force bombers to use when their bases got taken out by Soviet ICBMs – and one mile of every five is straight and level for this reason.
+Like many Americans I have heard this before and in fact, the specific highway identified by my acquaintance (a certain stretch of I-80 in Nebraska) I have also previously heard as an example location.
+This is the type of thing that enough Americans have heard that it becomes accepted through cycles of repetition. To anybody who has driven the endless straightaways of I-15 in Utah or I-70 in Kansas it probably seems reasonable that bombers could land there, and there is usually somebody in earshot to interject “yes he’s right, I’ve heard that too”.
+“One-mile-in-five” and the military on the Interstates in general, has equal portions of real fact, misconstrued things, and outright error. Mostly in wwiiafterwwii I cover weapons and equipment; for readers who prefer that I will return to that in the future. Perhaps this will be of interest however.
+https://wwiiafterwwii.wordpress.com/2024/07/25/wwii-the-autobahn-ike-the-interstates-and-one-mile-in-five/
+===== Wisconsin =====
+== Alphabet Soup: Why Wisconsin’s County Highways Are Lettered, Not Numbered ==
+The State's Road-Naming System Has Been In Place For More Than 100 Years
+Jenny Peek - November 27, 2019
+If you’ve taken a drive on one of Wisconsin’s iconic scenic roads, chances are you’ve noticed a bit of alphabet soup.
+Signs with names like BB, CV, N and SS flank Wisconsin’s county roads, and Shelly from Marshall wanted to know why.
+She asked: “Why are Wisconsin’s county roads labeled with letters instead of numbers?”
+So WPR’s WHYsconsin reached out to Daniel Fedderly, executive director of the Wisconsin County Highway Association — a nonprofit organization that represents the state’s 72 county highway and public works departments — to find out.
+https://www.wpr.org/transportation/why-wisconsins-county-roads-are-lettered-not-numbered
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 https://www.latimes.com/california/story/2023-08-01/why-highway-ramp-meters-dont-seem-to-reduce-congestion
+== Why does traffic bottleneck on freeways for no apparent reason? ==
+Drivers tend to flow remarkably well as a pack — until there’s an unusual event…
+Peter Dunn - February 19, 2009
+When something disturbs the normal course of traffic, the effects can last for a surprisingly long time after the incident itself is gone, and affect areas far from the initial problem.
+“Maybe a dog runs into the road,” says Moshe Ben-Akiva, professor of civil and environmental engineering and director of the MIT Intelligent Transportation Systems program. “Maybe people slow down to look at something. Maybe someone cuts someone off and they start arguing. The cars at the front get moving again after a couple of minutes, but cars behind them still have to stop and queue up. It’s like a shock wave that moves upstream.”
+The phenomenon is portrayed eloquently in MITSIMLab, a traffic simulator developed at MIT in the 1990s with funding from Boston’s Big Dig highway project. During a recent demonstration of the software, graduate student Samiul Hasan set up an animated map of downtown Boston highways to simulate traffic on a typical weekday morning.
+Thousands of colored rectangles representing individual cars, trucks, and buses ply the roadways, each moving according to its own parameters for desired speed and driving habits, which include following distance and “gap acceptance.” The overall model reflects the distribution of driving behaviors aggregated from traffic models that are based on video studies conducted in Boston, Los Angeles, San Francisco, and other locales.
+https://engineering.mit.edu/engage/ask-an-engineer/why-does-traffic-bottleneck-on-freeways-for-no-apparent-reason/