I don't know about cabbie's contracts, but Uber offers this as an option (including in Chicago). https://www.uber.com/chicago-drivers/services/uberCAB/ https:/

I don't know about cabbie's contracts, but Uber offers this as an option (including in Chicago). https://www.uber.com/chicago-drivers/services/uberCAB/ https://www.uber.com/chicago-drivers/services/uberCAB/ As a customer, I've only done it because I wanted a cab after a concert and didn't want to wait in line -- I walked two blocks and used Uber to hail a cab instead. You pay meter fare plus tip and the whole thing is charged through the app.