I also believe that the majority of "city" nighttime driving scenes in TGJ (including where Jarvis Goodland is pulled over) are filmed on S Sepulveda Boulevard, LA. But I'm happy to be corrected on this one..
Apparently that's where the gas station was located.
Yes, it's still there today with the "76" logo on it...
And I think that when they first go mobile (when following Jarvis) both cars turn onto S sepulveda from S La Tijera Boulevard- but it's hard to say as it was filmed over 40 years ago and the storefronts have all changed.