In 1994, as part of the Cross Harbour project in Belfast, a Motorway Control System (MCS) was commissioned to inform drivers of prevailing traffic conditions or incidents, and to assist the selection of the correct lane for onward travel (with 5 lanes of traffic this length of the M2 is the widest section of motorway in Northern Ireland). The original design included eight gantry mounted rotating prism variable message signs (RPVMS) with the dual functionality of Advanced Directional Signage and alternative legends advising of the closure of the M3 Lagan Bridge.
The RPVMS were approaching the end of their economic life and their reliability was inconsistent. Following a stakeholder’s workshop (including TransportNI, the Police Service of Northern Ireland and the Road Operator) a preferred option for replacement of the existing signs with new MS4 technology was identified.
The project was tendered in November 2013 on the basis of the design, procurement and technical approval of eight portal-gantry mounted MS4s (8x12).
Following the structural survey of the existing gantries, work began to remove the obsolete VMS along the M2 & M3 Motorways in April 2014, with the retrofitting of the new MS4s and access platform assemblies being completed by the end of June 2014.
To minimise downtime of the MCS, the sites were carefully sequenced with night road closures only. The entire assembly (signs and platforms) were lifted and fitted into position as an integral unit to minimise work at each gantry.
The new signs enable the proactive management of traffic along this strategic section of the motorway network with improved responsiveness. The whole-life costs of maintaining the new signs in comparison to the old RPVMS technology, creates significant long-term savings. The MS4s have the capability of displaying pictograms and EMI aspects along with text messages generated at the instation.