San Bruno, CA has a population of 42,000 yet has quite a few highways, in fact almost the same highways that go to neighboring SF with a population over 20x (it actually borders SFO but one can still count SFO as part of SF.)
San Bruno: I-280, I-380, US 101, CA 35, CA 82
San Francisco: All of the above, except replace I-380 with I-80.