It’s reassuring to know that I wasn’t the only one who noticed this inconsistency in traffic patterns. People returning from LA/Orange County does sound plausible.
I lived a number of years in the SF Bay Area and I learned to take advantage of the counter commute patterns. This was the ticket to maintaining sanity. For those of you who are familiar with the Bay Area traffic patterns, I commuted from the Penninsula north on 280 in the morning. It was a sea of red tail lights all the way from SF as people commuted to Silicon Valley. Since I was going counter commute, I easily breezed into the city.