Paramics Model predicts journey time delays for vital roadworks on the Erskine Bridge in Scotland
SYSTRA have worked with Scotland Transerv for a number of years, modelling various Traffic Management (TM) impacts on the A898 Erskine Bridge using Paramics.
In 2017, Scotland Transerv proposed a fast lane closure in both directions on the bridge deck. To gauge how significant the delays could be, SYSTRA modelled the fast lane closure TM proposals in the Paramics model. The model was based on the TM design drawings and video footage of previous TM on the bridge.
Results from the modelling indicated journey times of around 45 minutes on the M8 Westbound approach. Bluetooth journey time surveys were undertaken during the works and subsequent analysis showed that observed peak journey times on the M8 Westbound approach were very close to the modelled 45-minute journey time. The other routes to the bridge were also analysed showing a good correlation in all cases.
One major factor in accurately replicating the observed journey times was observing traffic behaviour (speeds and headway) through similar previous TM works on the bridge and making adjustments in the Paramics model to best replicate that behaviour.