Many drivers, when they see a “lane closed ahead” sign, move over right away ... encourage drivers to late merge, or zipper merge, when traffic is heavy. Utah has even made it the law.

The tricky part is that a lot of people think they need to merge early when they see the arrow sign, but that creates one dense line of traffic and leads to longer backups when traffic is heavy.

Then they take turns merging. It amazes me that this traffic concept is so slow to catch ... even though no sign indicating a road closure was yet in sight. I felt uncomfortable continuing in ...