In message , at 06:13:10 on Sat, 21 Jan
2012, Adam H. Kerman remarked:
I didn't realize there were no transponders. It's enforced entirely
with photographs of license plates?

Even toll roads in the USA are enforced by photographs of licence plates

No one enforces toll collection with photographs of license plates as
the primary system of enforcement. It supplements transponders.

We may have a problem with the word "enforce". While it's true that
transponders are the primary means of collecting [US highway] tolls,
supplemented in many cases by a cash-lane, what the cameras are doing is
enforcing a regime where people need a transponder (or to use the
cash-lane).

In the UK we talk about "Law Enforcement" to mean the way in which
people like the police ensure people obey the law by various means, but
primarily by the pursuit of offenders.
--
Roland Perry