Last time I checked, most cabs in LA do not have on-board credit card scanner so they have to radio the dispatch to get approval. This could take as long as 5 or 6 minutes. If you are in a hurry, don't wait until you are at the destination to tell the driver you are paying with credit card.
You should tip a little bit extra with credit card to make up for the fees that cab company takes from the driver.
And they complain incessantly if you try to use a card - the cabbie has to eat a 10+% fee imposed by the cab company.
A cabbie in PHL tried to pass that fee on to me in PHL, I said screw that and fortunately had just enough cash left in my wallet to pay for it. I didn't even think businesses were allowed to pass the credit card processing fee onto customers - and I also know that the merchant's processing fee is nowhere near 10% which is what the cabbie tried to charge me. The fees are closer to 2-3%, if that.
So, in other words, bring cash. If you get charged a fee, it's not worth any points or miles you get on your credit card.
I found that MetroCab in Santa Monica takes credit card, and there was no additional fee for me, over what I would have paid for with cash. There was no complaint and cabbie was generally nice about it.
The other cab, on the way back from LAX though, said he could, but that his machine was broken, too much trouble, and complained a lot like a lazy bum, so I just begrudgingly gave him cash. Then, he wouldn't give me a receipt so I could get reimbursed by my company! grrr..
A cabbie in PHL tried to pass that fee on to me in PHL, I said screw that and fortunately had just enough cash left in my wallet to pay for it. I didn't even think businesses were allowed to pass the credit card processing fee onto customers
They're not supposed to (not supposed to have a minimum either), and can get in trouble with the merchant processing company for doing it, but it still happens.