I'm working on the maps for cahighways, and I'm up to 215. I noticed that the PM for Route 215 are not at 0.000 in Temecula. They are at around 8.5, and nothing lower than that is in the PM tool. Does anyone have an idea why? Where did 215 (or, more likely former 194) actually start? Old 395 and....
The current I-215 alignment was built as two-lane 395 before 1964. When 395 became 15 and 194 in 1974, 395's postmiles were kept on 194. Presumably they're now R postmiles due to minor changes when the road was four-laned.
tldr: it counts from the county line on I-15.
It may count from the county line; but it's not in the postmile system anymore, having been allocated to 15. Interesting. I'll make a note of it.
This would mean that the I-215 exit numbers don't correspond to the Riverside County postmiles. Interesting; during several years living in Redlands and using I-215 regularly I didn't notice the discrepancy. Will have to check it out when I'm down that way later this year!
I did a post mile tool near the start. I got PM of RV 8.8, but statewide odometer of 0.37. They base exit numbers on the statewide odometer. (It also pointed out that Calnexus moved their pages at some point, and I need to go fix all my links).