Just had a little thought after posting the above location, and had a little looksie for another scene from The Wrong Crowd
and sure enough, the scene where we see Michael & KITT (in convertible mode)
do a 180' by the hitchhiker was also filmed on Del Valle Rd, but further west along it.
The location of the 180' is;
The following SPM scene was also filmed on the same stretch, heading back in the direction of where the San Francisco & Millston
sign was located in the pilot and the above location of the pumpjack.