In this case, having successfully completed 1,400 in a short amount of time will give Cruise’s engineers loads to work with.
Cruise is permitted to test about 180 Generation 3 vehicles on public roads in California. It didn’t state how many vehicles were needed to complete this test.
The 24 hours part seems open to abuse. Anyone/thing can make an unprotected left at 3-4 am.
1,400 turns with 180 cars is less than 8 turns each in 24 hours. One turn every 3 hours...
(Likely not the whole fleet involved).