Credit Card Programs - Best Card for Taxis?

What is the best card for earning points on taxi rides? My girlfriend has to take at least two long taxi rides/day for work and I want her to be able to maximize her mileage. I know the Sapphire Preferred gives 2 points for travel which includes taxis, but is there anything else out there?

I use the Sapphire Preferred too and would in her situation.

I use the Sapphire Preferred too and would in her situation.

+1 Chase Sapphire all the way! ^