"Average-speed cameras".
Under the law of "double jeopardy" (
procedural defence that forbids a defendant from being tried again on the same, or similar charges following an acquittal or conviction one may be able to claim innocence), if stopped in an "average zone", then one might claim that since the "average speed" was maintained, that any "overspeed" is therefore not applicable under the term of double jeopardy, especially as "average speed" infers that some overspeed is permissible.
Secondly: As a driver's (or biker's) instruments display average speed, then one can argue that this is as equal a system to control speed than the monitoring system itself, and thus it may be argued that any overspeed is irrelevant (remembering of course that in order to comply, one must average out the driving (or biking) speed).
Nationally, average speed systems are growing in number (a form of plague

) and being linked between regions. Thus, the true zone should be displayed (entry and exit) in order for the person to be made aware of the regulation. Any good lawyer (such as those used by footballers, celebrities etc

) would easily be able to argue these points.
Thus, for instance, raiders leaving a bank after a gold heist may only be done for the raid and not the fast getaway.
