New design interchange development that reduces congestion and accidents is under way in the USA

Interchanges on expressways have many lane changes and confluence of cars, which can cause traffic jams in places where car traffic is heavy and the possibility of contact accidents will be very high. To alleviate this problem in the US "Diverging diamond interchange (DDI)"We are promoting the introduction of a newly designed interchange called"

A new intersection design eliminates the dreaded turn into oncoming traffic | The Independent
https://www.independent.co.uk/life-style/gadgets-and-tech/intersection-design-eliminates-dreaded-turn-into-oncoming-traffic-a8250471.html

By adopting the interchange of DDI design, why the smooth traffic can be realized is understood by seeing the following movie.

Diverging Diamond Interchange Visualization - YouTube


The following extends straight from the lower left (west) to the upper right (east)Interstate Highway Route 40 (I-40)And the DDI design interchange connecting the 123 road extending from the upper left (north) to the lower right (south) crossing I-40. Although it can be felt in a complex shape at first glance, it has the effect of smoothing the movement to the destination.


The No. 123 road is shaped so that the left and right are interchanged at the part between the entrance and the exit of I - 40 ... ...


Signals are installed in the part before the change, and it is controlled so that only the car on one side road can pass.


The car leaving the I-40 has a signal like a green arrow, and when entering the entrance in the opposite direction there is no signal to block traffic and there is no need to cross the oncoming lane, so smooth turning is possible.


In the part crossing the highway, road signs are installed and it is prevented from accidentally entering the expressway.


A car running north on the 123 road like the blue line, the lane changes in accordance with the signal before the bridge crossing I-40 ......


I will take the left side of the bridge crossing I-40. After crossing the traffic light on the other side, you can return to the original right road.


If a car running north on the 123 road uses I - 40 in the west direction, if you drive in the left lane like a yellow line, you can use the expressway smoothly .


On the contrary, if you head east, you can use I - 40 from the right lane like an orange line. Therefore, if you are running in the lane in which you want to go, you can use the freeway heading in that direction.


If you leave the exit on the west side of I - 40 and go to the north, you just have to be on the lane on the left side, so you reduce the risk of mistaking the road as much as possible.


Bicycle traffic is also considered, and the light blue line is a road for bicycles heading north 123 from the south. The road for the bicycle is also shaped like a car as the right and left roads change.


Pedestrians pass orange lines. When crossing the highway it is designed to pass through the center of the bridge, and both sides are surrounded by a barrier, so safe passage is possible.


In the US, development of this interchange has been in progress since 2009, and at the time of article creation, we changed 62 interchanges to 22 DDI designs in 22 states. It seems that collision accident has decreased by 33% after changing to DDI.

After changing to DDI, when we took a questionnaire to the driver, 95% answered "I felt traffic jammed as relieved", and 97% of drivers said that they were "safe" . As the effect of changing to DDI is also certain, at the time of article creation, many American interchanges are planning to switch to DDI design, and construction is under way.