M62-M1 interchange-a combined TRANSYT/ VISSIM micro- simulation assessment

In 2004, Faber Maunsell, under the newly established 'Network Analyst' role in the Highways Agency's (HA) Northern region, carried out a VISSIM micro-simulation study of network congestion in the vicinity of the M62 - Ml Lofthouse Interchange near Leeds, West Yorkshire. This was in response to a complaint made to the Network Strategy and Traffic Operations Directorates through one of the HA's Road User Forums, of perceived unnecessary delays to some traffic using the east- bound M62 between Junctions 28 (Tingley) and 29 (M1 Lofthouse Interchange). The aim of the project was to identify low-cost 'early-win' schemes which could be implemented prior to, and which would compliment the £1.2bn proposals to increase capacity on the Ml and M62 motorways in Yorkshire, as announced by the Secretary of State for Transport in March 2005. Innovative designs, intended to maximise the capacity of the existing available road space were developed and, using VISSIM micro-simulation models, were shown to have significant benefits for motorway users in terms of eliminating existing congestion problems through achieving better segregation of the motorway traffic-flow streams. To limit scheme costs, intervention proposals considered under the project were restricted to revisions to road markings and signing to achieve more efficient motorway lane-usage and improvements to signal timing at the interchange roundabout to optimise junction throughputs, the latter of these requiring inputs to the VISSIM traffic signal simulations from a TRANSYT model of the interchange grade-separated signalised roundabout. In addition to the more usual numerical analysis, 3-D visualisation techniques were utilised to 'fly-through' the area and illustrate the potential improvements to traffic congestion in advance of scheme implementation and construction. This paper details the methodology adopted in the study and summarises the results of the intervention-analysis performed.