I was successful in using a Bank of America chip-and-sign credit card to buy gas yesterday, so some chip-and-sign cards do work. I was not prompted for a PIN. YMMV.
Citibank AAdvantage World Elite MasterCard DOES NOT work at the airport gas station after hours. This is a chip-and-sign card, not a chip-and-pin card.
I found that out awhile ago. The only card I carry that works is the new Diners Club. BTW, I had occasion to use their Primary Auto Insurance coverage a few months ago and was very satisfied with the way the claim was handled. Full coverage with zero deductible, and virtually everything done on line.