M8 Roadworks Management

THE CHALLENGE

The CSMM (Clyde Strategic Microsimulation Model) has been developed in S-Paramics to assist the design and testing of temporary traffic management layouts for the trunk road and motorway maintenance programme in Central Scotland. It has been operational since 2010. The model contains more than 1.5 million individually simulated vehicles on 250km of roads over a continuous 24hr period, and approximately 50 grade separated junctions.

Road closures and lane restrictions on motorways and trunk roads can result in severe congestion over a wide area, often in ways that are not anticipated. SIAS (now part of SYSTRA) built a model which includes the M8 through Glasgow and the Clyde Valley. The model predicts queuing, shock waves and blocking back both on and off line. It provides the means to help minimise these effects over a 24-hour period for both average and peak season weekdays.

In addition to the sheer volume of traffic, network geometry and junction layouts are principal contributors to congestion. Paramics Microsimulation software was chosen as the modelling platform because of its unique ability to include all the contributing elements of congestion and traffic flow over the entire study area within a single model. No other modelling system can meet this requirement.

The CSMM was defined in consultation with central and local government agencies. It adopts current and future predicted trip distribution patterns from the Transport Model for Scotland (TMfS) to ensure that strategic route, mode and destination choice impacts are reflected in the travel demand forecasting for the detailed testing of operational impacts.

SYSTRA’S ROLE

Data was collected by SIAS, Amey and Transport Scotland’s data collection consultants on turning counts, traffic flow data, journey times and speed profiles, to ensure model calibration and validation to a high standard.

The initial application has been the testing of temporary traffic management layouts required for the M8 Structures Refurbishment Strategy, which involves essential maintenance over a ten year period on structures between M8 junction 8 at Baillieston and junction 26 at Hillington.

In addition to meeting the client’s initial objectives, because it was designed with such extensive and detailed coverage, the CSMM has a high value added content which can be applied to applications well beyond the scope of the M8 Structures Refurbishment Strategy. These include:

• trunk road scheme assessments
• permanent traffic management scenarios
• lane management, including speed control and hard-shoulder running
• event and incident management
• modelling travel time reliability
• detailed emissions modelling
• testing of VMS and Intelligent Transport Systems
  The CSMM provides a consistent framework for trunk road network management, and can be used in conjunction with existing detailed Paramics Microsimulation models that cover surface streets in Glasgow.