Left turns are notoriously hat by drivers , and for just reasonableness . According to a 2007 written report from the National Highway Traffic Safety Administration [ PDF ] , closely a third of all crashes at intersections with dealings light involved cars turning left . waitress for the chance to twist is also time - consuming ( just ask anyUPS machine driver ) . But asWIREDreports , some main road architects have figured out a mode to do without them .
The " diverging diamond interchange " ( or DDI ) replaces the traditional layout of an intersection with a cagey designing that ’s more efficient and less potential to lead to accident . It works like this : At the intersection , two roadways carry oppose traffic temporarily swap sides , create a diamond shape . At the points where the roads intersect , traffic light baffle who crosses when . ( For a better idea of how they function in existent life , you could check out the video below from the Florida Department of Transportation . )
The biggest difference with the design is that drivers turning provide no longer have to force out in front of oncoming traffic to do so . They can easy wrench onto the diverge exit lane when push on the diametrical side of the route .
The concept gained popularity in the U.S. after a grad student named Gilbert Chlewicki write a term composition detail it . Even after light upon that the French had been using his idea since the 1970s , he preserve to kick upstairs it here in the States . Today there are 62 DDIs in 22 state , and their effectualness indicate that they ’re here to stay .
Last twelvemonth , researchers feel that diverging adamant edit accidents by 33 per centum and fatal accidents on terminal incline by more than 60 per centum . The drivers who use it were also ascertain to seldom make error . According to a study conduct at America ’s first DDI in Springfield , Missouri,97 percentof drivers said they feel good on it . More of these crossroad are being planned for highways across the country .
[ h / tWIRED ]
