That’s the San Joaquin Valley? I noticed that on the map. It seems really thin between the San Francisco-Modesto area and Bakersfield.
Yes, it’s the San Joaquin Valley and it’s really sparse. There are many offramps with services now and has been for a number of years.
When I-5 was first completed and for several years after, the services were few and far between. California Highway Patrol carried 5 gallon gas cans with them for those stupid enough to run out of gas and there were many.
It’s that way till you get to the mountain range south of Bakersfield and start up the hill. That stretch over the mountains before you drop down into the LA basin is still referred to by many as the Ridge Route.