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Bob and I have discussed this situation. The main concerns are vehicle snag on the downstream edge of the door frame and exposed end of barrier downstream from the door frame for one way traffic. For cases of reverse-direction traffic, both exposed ends are a snag risk for errant vehicles.[Zickler(VDOT)]  that matches what I was thinking.

To mitigate snag risk, we have been guiding states to use a lateral transition or flare of 1:10, or 1 ft laterally to 10 ft longitudinally. Now, it can be challenging to feather reinforced concrete to zero. Thus, one may need to grind the wall down near the end to allow for larger thickness but a smooth transition at surface. What materials currently make up the walls in the tunnels depicted in photographs? [Zickler(VDOT)] walls are reinforced concrete and are covered by a fire proofing material that screwed on (similar to a ceiling tile) Is your door crashworthy? [Zickler(VDOT)] Not sure, I know it is not crash tested. What happens to door under MASH impact loading?[Zickler(VDOT)] I am fairly sure it deforms and causes a sudden deceleration.

The recessed door would also need to use tapered upstream and downstream edges. One option is to move door forward to eliminate exposed recession. If one cannot do this. Then, one must consider 1:10 transition there too.[Zickler(VDOT)]  makes sense to me.

A different option would be to use a structural gate that shields the entire opening. The gate would likely need to activate with ease upward when door access is required. Can you accept the use of a vertically swinging gate to allow access to door?[Zickler(VDOT)]  a swinging would likely be very difficult to get past the fire code if it swings into the roadway. Do you mean something that would rotate in a plane parallel to the plane of the door about an axis perpendicular to the roadway?  Counterweighted to move up and out of the way? The gate arm would provide continuity from parapet end to parapet end?  Similar to the fill in concepts we have been discussing for median barrier openings or temporary barrier closures but able to rotate up and out of the way? That might work.

If handicap access is not needed, one could raise door access to above barrier and add small strategically-sized steps into barrier face. A door on a platform would be easier to shield.[Zickler(VDOT)]  Handicapped access is required.  We are nailing down refuge behind the door for handicapped folks and an egress for the able bodied.

It may be helpful to verbally discuss options after knowing all of your tunnel constraints. Please let me know if a live discussions is desired to further brainstorm options and current ideas.[Zickler(VDOT)]  I am sure that would be helpful.  After Thanksgiving?

Thank you very much for your feedback.

Please see below for additional information.  I will send some sketches based on your feedback and then we can set up a time to talk.

I have another concept that I want to discuss but I will start a new chain.

Thank you very much for your help.