I-40 in North Carolina

[sprjus4]

This is just a curiosity question what would be the economics of two single direction lanes alternating with a more normal speed limit?

It would require a trail car. Trail as opposed to pilot. There would be a flagger at each end (probably more gate attendants) They would open the gate at one end and close it when it was empty or after a set time. The trail car follows the last car and stays in the back of all the cars. When it reaches the other end repeat the process the opposite direction.

What exactly is the benefit of doing this?

[PColumbus73]

This is just a curiosity question what would be the economics of two single direction lanes alternating with a more normal speed limit?

It would require a trail car. Trail as opposed to pilot. There would be a flagger at each end (probably more gate attendants) They would open the gate at one end and close it when it was empty or after a set time. The trail car follows the last car and stays in the back of all the cars. When it reaches the other end repeat the process the opposite direction.

What exactly is the benefit of doing this?

Agreed with @I-55, One lane is in both directions is better than alternating two lanes. It won't save much time when you have to hold one direction of traffic for however long. Both I-26 and 40 would basically be a long-term construction zone.

[LM117]

Looks like the new DDI at Airport Blvd. near RDU will open next week.

https://www.ncdot.gov/news/press-releases/Pages/2025/2025-03-06-airport-boulevard-i-40.aspx

[jdunlop]

Looks like the new DDI at Airport Blvd. near RDU will open next week.

I didn't venture out that way today, but news reports said that the Conversion was delayed due to problems with potholes on-I-40.  IIRC, that section was resurfaced by the contractor as part of the interchange project.  No word on a new date for the conversion.

https://www.cbs17.com/news/local-news/wake-county-news/diverging-diamond-interchange-near-rdu-delayed-after-major-pothole-conundrum-on-i-40/