The MBTA should add a $0.50 surcharge for loading your CharlieCard on a bus. When people pay cash on buses it slows everyone down. The MBTA understands this and set up fares to discourage paying cash:

• CharlieCard: $1.60
• Cash-on-board: $2.10

This makes sense: people can pay cash if they need to, but you save money for yourself and time for everyone else if you put money on a CharlieCard (RFID) at a fare machine instead.

The problem is, there's a loophole: the bus also lets you put cash on a CharlieCard. This is an even longer process than paying with cash: press a button, tap your card, put in cash, and tap your card again. And then you can immediately use the money on the card to pay your bus fare. Someone doing this saves themself $0.50, getting the discounted $1.60 CharlieCard fare instead of the normal $2.10 cash fare, while making everyone else wait.

A $0.50 surcharge would fix this. If you needed to you could still use the machine on the bus to load your card, but there would be savings for putting more money on at once: you'd only pay the $0.50 once per transaction whether you were putting on $2 or $20. And you could save even more money by using a fare machine, off the bus, where you wouldn't be holding up a bus full of people.