Topic: Road transport
A diverging diamond interchange (DDI), also called a double crossover diamond interchange (DCD), is a type of diamond interchange in which the two directions of traffic on the non-freeway road cross to the opposite side on both sides of the bridge at the freeway. It is unusual in that it requires traffic on the freeway overpass (or underpass) to briefly drive on the opposite side of the road from what is customary for the jurisdiction. The crossover "X" sections can either be traffic-light intersections or one-side overpasses to travel above the opposite lanes without stopping, to allow nonstop traffic flow when relatively sparse traffic.
Like the continuous flow intersection, the diverging diamond interchange allows for two-phase operation at all signalized intersections within the interchange. This is a significant improvement in safety, since no long turns (e.g. left turns where traffic drives on the right side of the road) must clear opposing traffic and all movements are discrete, with most controlled by traffic signals. Its at-grade variant can be seen as a two-leg continuous flow intersection.
Additionally, the design can improve the efficiency of an interchange, as the lost time for various phases in the cycle can be redistributed as green time—there are only two clearance intervals (the time for traffic signals to change from green to yellow to red) instead of the six or more found in other interchange designs.
A diverging diamond can be constructed for limited cost, at an existing straight-line bridge, by building crisscross intersections outside the bridge ramps to switch traffic lanes before entering the bridge. The switchover lanes, each with 2 side ramps, introduce a new risk of drivers turning onto an empty, wrong-way, do-not-enter, exit lane and driving the wrong way down a freeway exit ramp to confront high-speed, oncoming traffic. Studies have analyzed various roadsigns to reduce similar driver errors.
Diverging diamond roads have been used in France since the 1970s. However, the diverging diamond interchange was listed by Popular Science magazine as one of the best innovations in 2009 (engineering category) in "Best of What's New 2009".
The design also is promoted as part of the Federal Highway Administration's Every Day Counts initiative which started in 2011.
- "Diverging Diamond Interchange" | 2015-10-12 | 10 Upvotes 8 Comments
The Magic Roundabout in Swindon, England, is a ring junction constructed in 1972 consisting of five mini-roundabouts arranged in a circle around a sixth, central circle. Located near the County Ground, home of Swindon Town F.C., its name comes from the popular children's television series The Magic Roundabout. In 2009 it was voted the fourth scariest junction in Britain.
A Michigan left is an at-grade intersection design that replaces each left turn at an intersection between a (major) divided roadway and a secondary (minor) roadway with the combination of a right turn followed by a U-turn, or a U-turn followed by a right turn, depending on the situation.
- "Michigan left" | 2011-02-14 | 77 Upvotes 77 Comments
Don't Mess with Texas is a slogan for a campaign aimed at reducing littering on Texas roadways by the Texas Department of Transportation. The phrase "Don't Mess with Texas" is prominently shown on road signs on major highways, television, radio and in print advertisements. The campaign is credited with reducing litter on Texas highways roughly 72% between 1987 and 1990. The campaign's target market was 18- to 35-year-old males, which was statistically shown to be the most likely to litter. While the slogan was not originally intended to become a statewide cultural phenomenon, it did.
Beyond its immediate role in reducing litter, the slogan has been popularly appropriated by Texans. The phrase has become "an identity statement, a declaration of Texas swagger". Though the origin of the slogan is not well known outside of Texas, it appears on countless items of tourist souvenirs. Since the phrase is a federally registered trademark, the department has tried at times to enforce its trademark rights with cease and desist letters, but has had very limited success. The slogan is the title of the book, Don’t Mess With Texas: The Story Behind the Legend.
"Don't Mess with Texas" has been awarded a plaque on the Madison Avenue Walk of Fame and a place in the Advertising Hall of Fame, a distinction given to only two slogans annually.
"Don't Mess with Texas" is also the official motto of the Virginia-class submarine USS Texas.
In 2011 the result of a public vote for the best "Don't Mess with Texas" ad over the last 25 was revealed, the winner was one created by the Commemorative Air Force (then called the Confederate Air Force). The ad involved the CAF's Boeing B-17 "Sentimental Journey" pursuing and retaliating against a truck from which trash was thrown.
- "Don't Mess with Texas" | 2020-04-21 | 218 Upvotes 190 Comments
The Great Britain road numbering scheme is a numbering scheme used to classify and identify all roads in Great Britain. Each road is given a single letter, which represents the road's category, and a subsequent number, of 1 to 4 digits. Introduced to arrange funding allocations, the numbers soon became used on maps and as a method of navigation. Two sub-schemes exist: one for motorways, and another for non-motorway roads. While some major roads form part of the International E-road network, no E-routes are signposted in Great Britain, or the rest of the UK.
The scheme applies only to Great Britain (England, Scotland and Wales); a similar system is used in Northern Ireland, as well as outside the UK in the Isle of Man, Jersey and British overseas territories. These other numbering schemes use similar conventions.
- "Great Britain road numbering scheme" | 2020-12-31 | 42 Upvotes 59 Comments