>>VO:Today, our communities face a growing number of transportation challenges.
As traffic volumes grow and congestion worsens, motorists, pedestrians, and cyclists
confront greater risks at intersections.
We need balanced solutions that improve safety and keep people moving.
At the Federal Highway Administration, our first priority is safety,
and our mission is to improve mobility for all users of our nation's highways.
In support of these goals, we've been evaluating innovative intersection designs for many years.
>>VO: Where they have been built, travelers save time, agencies save money, and
communities benefit from safer facilities.
One Innovative Intersection Design, The Restricted Crossing U-Turn,
can dramatically reduce crashes related to crossing
and turning left at intersections along busy multi-lane highways
At many intersections the critical question is how to address left turns
How they are treated has an impact on the efficiency of the intersection
and can reduce a crash type that tends to be quite severe
>>Joe Hummer, Ph.D., P.E.: Alternative Intersections are worth considering because they
deliver more for less. They get more cars through the same spaces than a conventional intersection
and they deliver better safety then a conventional intersection
>>VO: The Restricted Crossing U-Turn or R-CUT intersection, also known as a J-Turn or Super Street
changes how traffic from the minor road enters or crosses the main highway by relying on
a combination of right turns and U-Turns
Multi-lane high speed divided highways function as vital economic links between cities and communities
reducing travel times and improving safety for longer distance trips.
However, along these routes access for local residents and adjacent businesses is also important
Intersections, while providing this access, can be challenging in these environments
Motorists crossing the highway or turning left from the minor road must gauge
traffic approaching in both directions across a wide area.
A difficult task if speeds are high. Should a crash occur the result can be deadly
The R-Cut is an intersection design that provides access in a much safer way
while also improving operations along the highway. Let's take a closer look at an example
of an un-signalized R-Cut, sometimes called a J-Turn, in a typical rural setting
Notice that traffic traveling along the main highway can still continue through and
turn left or turn right at the intersection. No different than at a conventional intersection
Where an R-Cut differs is in how it handles vehicles entering or crossing the main highway
from the minor road approaches. Channelizing islands at the intersections
force the minor road traffic to turn right, joining the traffic on the main highway
Shortly there after a median U-Turn allows the minor road traffic
to proceed in the opposite direction, the equivalent of a left turn. Or to then turn right
and continue travel along their original minor route.
The equivalent of crossing the main highway at a conventional intersection
By eliminating two of the highest risk movements from the intersection
and replacing them with U-turns and right turns, safety is substantially improved
The total number of conflict points are reduced
and those that remain are less significant. Most importantly studies show that injury crashes
are reduced more than 40% and fatal crashes are reduced 70%
compared to conventional intersections. One of the trade offs with R-Cut Intersections
is that vehicles entering from the minor road travel slightly longer distances as compared
to a conventional intersection. However, when R-Cuts are implemented
along a signalized corridor the average travel times can actually improve. Hence the name Super Street
>>Bastian Schroeder, Ph.D.,P.E.: There is the reliability aspect where the Super Street will reliably
give better performance to everybody on that corridor. So the little bit added
inconvenience outweighs the greater capacity benefits and also the
safety benefits. A Super Street is a very safe corridor
>>VO: One of the unique features of the Signalized R-Cut or Super Street corridor
is the ability to synchronize traffic from one intersection to the next.
Easily adapting signal timing to heavy or light traffic volumes
>>James Dunlop, P.E.: One of the nice things about Super Streets and really where the name came from
is that you separate the two main directions of travel on your main artery.
So what you've done is create two one way streets. Since they're all two phase signals
you also reduce the cycle length which also increases the efficiency
and you have drivers on the side street waiting a lot less then they would at a traditional eight phase signal
>>VO: R-Cut intersections have been built with pedestrian facilities
including marked cross walks, refuge islands, and pedestrian signals
whether signalized or un-signalized the R-Cut can be an excellent choice for intersections
along divided highway corridors. Not only is it safer the R-Cut can be
a cost effective choice for locations where additional capacity or even a full
interchange may be needed in the future.
>>Don Bennett, P.E.: One of the beauties of the Super Street is the flexibility you have in implementing it
You can take a thirty year design life for a Super Street and you can go ahead
acquire the right of way and put in the asphalt for the dual left turns and dual U-Turn movements
and all of the things that you may need in that thirty year time frame
The Federal Highway Administration encourages
communities and agencies to consider the Restricted Crossing U-Turn
to improve the safety and efficiency of existing intersections as well as an option for new intersections
For more information about the Restricted Crossing U-Turn and other innovative intersection designs
Please visit safety.fhwa.dot.gov
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