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WIS 29 (County FF-County U) Freeway Conversion - Frequently asked questions (FAQ)
FAQs - General | FAQs - J-turns
- What is a J-turn intersection?
- Why are J-turns effective in enhancing safety?
- Why is a J-turn proposed at WIS 29/County VV?
- Why isn’t a J-turn proposed at WIS 29/County U?
- Are there any J-turns in Wisconsin?
- How much extra travel time is involved in a driving a J-turn?
- Are large vehicles able to use a J-turn?
- How long will the J-turn be effective?
What is a J-turn intersection?
This is an intersection that prevents direct crossing and left-turn movements from the side road. These side road movements are made indirectly by making a right turn, traveling about a quarter-mile on the divided main road, and then making a U-turn to proceed in the opposite direction on the main road toward the intended destination.
At the original intersection location, both left and right turns from the divided main road, as well as right turns from the side road to the main road, remain as direct turns. The J-turn does not require mainline through traffic to stop or yield.
Why are J-turns effective in enhancing safety?
J-turns reduce the number of intersection conflict points from 42 to 24 and reduce the right-angle conflict points from 24 to four. The remaining conflict points are merging, exiting, or lane-changing maneuvers, which are not right angle and generally result in lower severity crashes. Studies done by the National Cooperative Highway Research Program show J-turns provide significant reduction in right-angle, “far” side crashes.
Why is a J-turn proposed at WIS 29/County VV?
A J-turn is expected to reduce a significant number of the severe, right-angle, “far” side crashes. Relative to other improvement concepts, it is a low-cost treatment that can be quickly implemented, does not require property acquisition or relocation of homes and businesses, and minimizes environmental impact.
Why isn’t a J-turn proposed at WIS 29/County U?
The WIS 32 interchange is relatively close to the location where the west U-turn would be located for County U. Therefore, WIS 32 will be used to allow motorists to make a U-turn.
For the U-turn location to the east, a horizontal curve exists near the intersection. A safe U-turn location was not available within approximately a quarter-mile of the intersection. The County VV intersection can be used to make a U-turn. Motorists on County U can also travel west on Glendale Avenue or County VV and access WIS 29 at County VV.
Are there any J-turns in Wisconsin?
There are more than a dozen locations that have funding approved and are being designed for future projects. This J-turn will not be the first constructed in the state.
How much extra travel time is involved in a driving a J-turn?
It can be expected to be less than 60 seconds.
Are large vehicles able to use a J-turn?
Yes. The J-turn at WIS 29/County VV will be designed to accommodate the turning widths of large vehicles, including large tractor-trailer combinations and school buses. A weave analysis will also be performed during the design process to ensure that the median crossovers are constructed at an appropriate distance from the side road intersection.
The weave analysis will determine this distance by evaluating available gaps in traffic on WIS 29 in combination with the length required for larger vehicles to turn onto WIS 29, accelerate, and merge safely into the median lane so that they can negotiate into the median crossovers.
How long will the J-turn be effective?
It is expected that the proposed J-turn will provide a safer intersection than the existing configuration even as traffic volumes continue to increase on WIS 29. Because of this, the J-turn will continue to be effective until an interchange is constructed at the WIS 29/County VV intersection.
View more information about J-turns.
- Why build J-turns?
- How to drive a J-turn.
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Last modified: April 21, 2014
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