The road to San Francisco is frequently blocked up in both directions thanks to commuters from Silicon Valley and reverse commuters from the Mission headed to startup gigs in San Mateo and Palo Alto. The jam clears out for roughly five hours between 10:30 in the morning and 3:30 in the afternoon, and the chore of driving 280 is replaced by the joy of speed.
Because 280 is wide and has a number of banked turns, dot-com millionaires use this stretch of asphalt to exercise their Teslas and Porsches. This means that traffic moves at 85 mph despite the 70 mph speed limit and that smart drivers can comfortably kick it up to 90 without worrying about driving conspicuously faster than the other folks on the road. Gorgeous views don't hurt, but you'll want to get off before the traffic starts again north of San Jose.