  Modelling and simulating the traffic of heavily used but secure environments
such as seaports and airports is of increasing importance. Errors made when
simulating these environments can have long standing economic, social and
environmental implications. This paper discusses issues and problems that may
arise when designing a simulation strategy. Data for the Port is presented,
methods for lightweight vehicle assessment that can be used to calibrate and
validate simulations are also discussed along with a diagnosis of
overcalibration issues. We show that decisions about where the intelligence
lies in a system has important repercussions for the reliability of system
statistics. Finally, conclusions are drawn about how microsimulations can be
moved forward as a robust planning tool for the 21st century.
