The wiki article was good enough, appreciate the link.
So yes, I don’t recall ever seeing that, but… DUDE, neato! I can see that eliminating a lot of wasted time and improving safety, thinking specifically about a couple of the interchanges around here. But, I don’t think they’ll be adopted here anytime soon. From the wiki disadvantages:
Allowing exiting traffic to reenter the through road in the same direction requires leaving the interchange on the local road and turning around, e.g., via a median U-turn crossover. This affects several use cases:
- Drivers who take the wrong exit
- Bypassing a crash at the bridge
- Allowing an oversize load to bypass a low bridge
I can totally see that one being the deal-breaker here. Around here, the feeder roads run along the freeway for miles and miles. In urban areas, it is unusual to see a stretch of freeway without a feeder road. We have business driveways lining them. Texas even has its own subsection (the largest, of course) in the service road wiki article. To do the double crossover here, they would need to build a straight through lane alongside the freeway, which they already do when they have cloverleaf interchanges, which they do a version of here:
But there would not be nearly enough space to do either someplace like this:
Ooh, or here… another cluserfsck intersection:
*The OCD in me is disturbed that the middle picture is actually the farthest north.