The Solution
The decision was taken to use discrete-event simulation to model
road traffic flows, since the port consists of a series of process
steps, each proceeded by orderly queues rather than a melee of
interacting vehicles. The port is rich in data, with excellent
historical data on ferry schedules, vehicle/passenger carryings and the
arrival rates for different traffic types. The port has also invested in
Blip Systems’ Blip-Track system which anonymously senses mobile phone
and SATnav signals to monitor transit and dwell times of traffic on
approach and through the port.
Modelling the port’s traffic flows provided a number of useful
insights. The first was that the infrastructure can handle traffic well,
and delays were generally because of technical issues rather than
capacity limits, such as IT problems requiring slow manual check-in
processes or staff shortages. Secondly, it showed the importance of the
port’s Buffer Zone in providing flexibility within the system.
The next step was modelling future traffic volumes with three
forecasts: expected, optimistic and pessimistic were created, based on
varying assumptions and the use of sensitivity analysis to pinpoint
future pinch-points. A key performance indicator was included, looking
at the number of times a year the emergency traffic protocols had to be
employed.
The model showed that the physical infrastructure of the port could
suitably cope with future demand, albeit with greater staffing levels to
handle traffic increases. Modelling also identified a costed,
sequenced set of investments that optimally addressed traffic growth,
together with critical traffic volume thresholds that should trigger
investments in the future.