I was driving a Thrifty Rental Car from BWI Airport to Rockville MD at 9:30pm on 3/6/19. Upon approaching MD 200 from I95 I saw a sign that this was a toll road. Since there was no toll booth to pay or pick up a ticket I drove on and activated the Plate Pass box mounted in the car, assuming that I would be notified of the toll by the Car Rental Co. Sure enough, 2 weeks later I received a bill for $63.96. During the four days I had the car I did not use any other toll roads. The back of the bill gives the correct detail - that I had only been charged for the one toll. The Thrifty Car Rental web-site states the following "you will be liable for and we will charge you: (a) all tolls incurred for such use (at the highest, undiscounted applicable toll rate); (b) a $15.00 administrative fee (FL - $9.99 per occurrence) for each toll incurred (subject to a $90.00 cap for such toll-related administrative fees for the rental period); and (c) all other applicable toll charges or fees, if any." The Toll rate for the trip should have been no more that $4.08 for the off-peak use (see https://mdta.maryland.gov/toll-rate-calculator). I have no idea what the extra $44 charge is for other than a rip-off.