>>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 the users of our nations highways
In support of these goals we've been evaluating innovative intersection designs for many years
Where they have been built travelers save time
agencies save money and communities benefit from safer facilities
One innovative intersection design, the median U-turn
mitigates the risks of the left hand turn
the driver passes through the main intersection and procedes to a median opening
where the driver makes a U-turn followed by a right turn
>>Joseph 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 than a conventional intersection
>>VO: 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
>>Jeffrey Bagdage, P.E.: The left turns at the intersection are the highest risk turns. So if you can eliminate those
you're significantly eliminating those higher risk turns
and the number of conflict points at those intersections
>>Chris Patterson: Yeah, I would definitely say that we respond to less incidents at this intersection
now that there is a Michigan Turn Around in both areas, both north and south
>>VO: The median U-turn, or the Michigan Left, where it has been in use since the 1960's
removes the left turns from the signal controlled intersection
on either the minor or major road. Or in some cases both
>>Jeffrey Bagdage, P.E.: Roadways that have Median U-turns can punch huge amounts of traffic through there
You can take intersections with 80, 90, 100,000 vehicles per day
and run those intersections with the two phase traffic signal
>>VO: The Median U-turn treatment involves the elimination of the direct left turns at signal controlled intes
from major and or minor approaches. To make a left at a Median U-turn
the driver passes through the main intersection and proceeds to a median opening
where the driver makes a U-turn followed by a right turn
drivers on the minor road who want to turn left onto the major road
must first turn right at the signal controlled intersection
and then execute a U-turn at the downstream median opening
and proceed back through the signalized intersection
Guide signs are provided and inform motorists as they approach the intersection
The Median U-turns themselves may or may not be signalized
>>Imad Gedaoun, P.E.: The Michigan Left treatment is one of our safest
roadway design, next to the freeway. This design reduces crashes
by decreasing the conflicts and also the congestion
>>VO: The Median U-turns concept is also very adaptable. Although typically a corridor treatment
it has also been used successfully for isolated intersections to address a left turn hazard
Median U-turn treatments can be applied at interchanges as well
Median U-turns have been implemented along roadways with both narrow and wide medians
When the median width is narrow extra pavement or loons or bumpouts
Can be installed to accomodate larger vehicles [music][traffic sound]
Relocating the left turn reduces the number and complexity of conflicts
between traffic and pedestrians and bicyclists
Especially at the far side of the turn. Instead of being used for left turn lanes
The median space at the intersection between aposing directions of traffic
can instead be designed as a pedestrian refuge area
allowing people to cross the intersection in two shorter, safer stages
>>Jeff Bagdage, P.E.: The highest risk issue for pedestrians is the drivers in the left turning vehicles
but when they're only dealing with the right turning vehicles in front of them it tends to be
easier for the pedestrians and there's more visibility for the pedestrians as they are crossing the roadway
>>VO: The Median U-turn can reduce the number of signal phases at the intersections
in some cases by as much as half, resulting in significantly improved efficiency
Studies have shown that 20% to 50% increase in capacity
>>Danielle Deneau, P.E.: Well we can improve capacity so traffic is more free flow through the area
Where we're only operating a two phase signal as compared to eight phase where you have direct left turns at it
The cross over signal will go green in advance of the main intersection
So that the platoon is gathered and then the main intersection will go green
So that everybody's together, all the vehicles are together as they drive through the corridor
This provides us with better progression, we get more capacity out of the intersection
>>VO: Median U-turns can be tailored to a variety of surrounding conditions
Median U-turns exist along heavy freight corridors
highly developed retail boulevards
busy regional arterials and even local streets
>>Joseph Hummer, Ph.D., P.E.: The good niche for a Median U-turn is two busy streets
two rather large volume arterial streets with relatively low left turn demand
>>VO: Michigan has constructed Median U-turns along corridors all throughout the state
going back more than four decades. Other states including Utah and Louisianna
have built Median U-turns with plans to build more in the future
By reducing the number of conflict points
the Median U-turns result in safer intersections and roadways
as compared to conventional signalized intersections
Moreover, the Median U-turn design can be less costly and quicker to build than a conventional design
And finally, the Median U-turn is an especially robust intersection solution
capable of effectively serving user needs and accomodating growth well into the future
The Federal Highway Administration encourages communities and agencies
to consider the Median U-turn to improve the safety efficiency of existing intersections
as well as an option for new intersections
For more information about the Median U-turn and other innovative intersection designs
please visit safety.fhwa.dot.gov
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