The carrate tag was never used (or valid) in a Region asset or, as far as I know, in a road asset. Its only use, that I am aware of, was in a route.
I raised a ticket with the helpdesk some time ago (2020/2021?) on this matter. QA got back to me to report that the carrate tag is now obsolete in all containers.
My query came about because of a forum discussion over how many different road vehicles you can have in a route/session running at the same time. There are some region assets where the creators claim that you can have 60 to 100 different vehicles simultaneously running along roads. The region assets they created certainly had that many car tags in the kuid lists but I could never see more than a few different vehicles at any one time. It was difficult to judge because a randomly generated list of items can easily contain many duplicates. However, statistically, duplicates are less likely when you are drawing items (in this case cars) from a larger pool.
The official documentation for the region asset states only 15 different vehicles were allowed (car0 to car14). There was never any documentation I could find on the number of car tags allowed in a route. The response that I got back from QA did not resolve the number of car tags question but it certainly quashed the carrate tag discussion.
