In the US tipping is expected for car service drivers/taxi, etc. for example I often use Carmel car and limo in the NY area. I always book the base fare online which doesn’t include the tip, because I prefer to tip in cash during the ride. The drivers usually subtly remind me as we’re pulling up to the terminal my ride is already paid for but the tip wasn’t included. A little tacky but I was already planning on tipping anyway.