I never know this, but the GA do not patrol all toll highways. One of our group had a broklen power steering hose on the remote stretch of 15D south of Cullican. We were there 4 hours. The toill road sent a mechanic, which was not free, but reasonable. Got us goign but we had to drive 45 min in the dark on bumpy road to get to a pemex to overnight.
15D from culliacan to Mazatlan is in bad shape, especially the last 100 km. 15D in Sonora is excellent and its also good from Mazatlan to Guadalajara.