WHY NETWORK CONSISTENCY?

摘要

Why network Consistency?The paper examines the background to the concept of network consistency beingrecognised as an important pre-requisite of successful operation of the high speedhighway network in England. The paper considers why network consistency is important,how it can be achieved and what factors need to be considered, understood andsuccessfully addressed in order to achieve the desired outcome. It will also detail some ofthe inconsistencies that have been observed and designed that have led to unexpectedoutcomes and inconsistent or confused driver behaviour on the network – in particular,between adjacent operational regimes (interventions): eg: between sections of hardshoulder running followed by a section of all lane running or a section of standard D3M.Definition: CONSISTENCY = adherence to common principles or form to provideuniformity across the constituent parts of a complex network. (In this case the EnglishStrategic Road Network).Why is a consistent network experience required?1. To enable users to safely negotiate the route (without hesitation, confusion orexperiencing unnecessary stress).2. To provide adequate and timely information that can be swiftly comprehended.3. To enable driver behaviour to be anticipatory and predictable4. To encourage compliance5. To maintain the concept of a ‘controlled’ environment (the paper will detail the meaningof this concept)6. To avoid the provision of contradictory information or direction to users (through staticor dynamic features on the network).7. To meet user expectations.8. To recognise the interface with adjacent road networks)How is a consistent network experience achieved?1. Through the provision and operation of a homogeneous strategic road network.Relevant features that have a material impact, on user behaviour, include:1. Overhead (gantry-mounted) signing2. Verge mounted signing3. Lining, studs and road markings4. Signalling: MS4 / MS3 / AMI5. Enforcement cameras6. LightingThe paper will identify the key features of the various operational regimes and the keyhazards that are likely to be affected. The paper will assess the potential impacts on roadusers, as well as specific user groups, in particular, maintainers, Traffic Officers, recoveryoperators and emergency services. This assessment will consider safety, operation,maintenance, and driver experience. In particular it considers the transitions betweenadjacent operational regimes.The conclusion of the paper will present the recommendations and future analysis toachieve network consistency on the English high speed road network.