Coordinating on-ramp queue control with adjacent local signal controller: an algorithm to assist ramp metering application
This paper describes a queue control algorithm which is able to coordinate its operation with that of an adjacent local signal control so that its efficiency is improved. A microscopic simulation model (AIMSUN) was used to test the operation of the new queue control algorithm and compare its performance with that of the standard queue control. The assessment has shown the new algorithm to be a significant improvement in reducing the variation of the release rate and the frequency of exceeding the storage capacity whilst the efficiency of utilising ramp space increased. Also, the new algorithm was found to be less sensitive to changes in ramp demand and some parameter settings originally found critical to the operation of standard queue control. For the covering abstract see ITRD E134653.
ACCESS CONTROL ON THE M6 MOTORWAY: EVALUATION OF BRITAIN'S FIRST RAMP METERING SCHEME
On 21 May 1986 the first ramp-metering scheme to be installed on a British motorway came into operation on the M6 near Birmingham. Designed by traffic consultants Wootton Jeffreys for the West Midlands Regional Office of the Department of Transport, the scheme is located on the southbound access sliproad at Junction 10. Its aim is to reduce the congestion which regularly disrupts traffic flows on the motorway at and to the south of the junction during the morning peak periods. The scheme is fully traffic-responsive and incorporates special procedures for determining on-line the capacity of the motorway. An extensive evaluation programme was undertaken to assess the effectiveness of the scheme in reducing delays on the motorway. The programme also included measurements on the adjacent all-purpose road network to assess the impact of the scheme on non-motorway traffic. Results from these assessments are presented, together with a short technical description of the M8 metering system.
A decentralized control strategy for freeway regulation
A multilevel decentralized control scheme, the cascading technique, with application to the regulation of traffic on an urban freeway is presented. Performance of the decentralized system is compared to the performance of a centralized and a fixed time control structure. It is shown that the decentralized structure performs better than the centralized structure when incidents (lane closures) occur on the freeway. The freeway is modeled in terms of the aggregate variables section density and section speed, and is considered as a system of interconnected subsystems.