Got a coupon out of one of the Palo Alto freebie papers and was able to just walk in and schedule a smog check at 4:45 on a Friday. Staff was friendly enough and the lead mechanic took some time to go over what might be causing high numbers on one section of my smog check even though it did pass. He knew exactly what the causes might be-- which isn't really rare knowledge, but he didn't have to look it up either, he knew off the top of his head. I looked up causes on the internet later and it was exactly as he mentioned. I don't get gas here, too pricey. But while I was there, they were mobbed with people buying gas. Guess that's Palo Alto for you.