Median Crossovers

[cgarlick]

We are designing a crossover. Shifting traffic across a 13' median. The diagram we reference is TA-39 from MUTCD. HOwever, in our experience, we feel the the diagram is ambiguous and agressive. However, we are just wondering what others think and use.

One additional comment is note 2 in MUTCD says to use a reverse curve using the design criteria in AASHTO GDHS. Does anyone actually build a reverse curve at a design speed of 70 MPH. it seems pretty excessive.

Any comments are welcome and encouraged.

 

[n3rei]

I checked the referenced diagram. I assume this is a temporary maintenance of traffic due to construction measure and not part of a permanent design. Keep in mind that the reference to TA-39 is a guide to signage and stripping and not an actual roadway design. If you are in fact expecting 70mph traffic to use this then get your roadway design people involved. SAFETY FIRST!!!

The reference to a reverse curve really does not apply to you since you are traversing perpendicullary only 25' +/-. That reference is for where a large reverse curve would fit say a 500' +/- median, and not for a simple lane change type scheme.

Also check your ADT's etc. to make sure it works. Closing the lane of opposite traffic may cause headaches if the roadway can't handle it.

Provide speed reduction if necessary for safety, and appropriate barriers, etc.