There really aren t any truck stops in the city. Most are either in the Ontario or Castaic area. There are a few commercial stations selling diesel fuel, but they aren t set up for over night parking.
The closest truck stops that I know of are in the Ontario, CA area, right off Interstate 10 freeway. From memory I think there are at least four to five stops on both sides of the interstate.There is an stop in downtonwn los angeles where I have seen big rigs stop for fuel, etc., just north of interstate 10. i think it is on Los Angeles or Main street.
I agree with Barry... Ontario has a decent one and it has a few restaurants and a 24 hour diner... it is called T.A.