With the increasingly widespread use of many
traffic management measures the focus of research
has changed in the last decade from, for example,
“architectural” issues, such as methods with
which to effectively monitor traffic and provide
increased user information through extensive use
of VMS and planning of management strategies,
to issues involving data acquisition and control or
enforcement. The more extensive the information
available on the operational state of a network,
and how it is changing over time, the more
accurate and effective any management policy
can be, through for example Variable Speed Limits
(VSL) and Hard Shoulder Running (HSR); where
choosing appropriate speeds and/or operational
lane strategies may depend on fluctuations in
traffic patterns which are not easy to discern and
system effectiveness is conditional on being able
to appropriately enforce speed and access.