On the operation of road tunnels diverse requirements are imposed. This has implications for the design of the areas in front of the tunnel portals, especially in the case of highway tunnel. Designing requires an analysis of the operational phase of the traffic and the use by the maintenance and emergency services. The focus of traffic lines on the middle stripe, providing equipment and vehicles of the maintenance and emergency services for use in the tunnel, the passing of vehicles of events and emergency services in the event of maintenance work, accidents or fire events and turning of vehicles in maintenance and police officers in normal operation.
Extraordinary traffic conditions cause next to the front of tunnel portals already high risk of accidents, an additional danger to road users. The research provides the necessary technical basics in the fields of position and geometry as well as optical guidance and recognition of lanes reconciliation, institutions of passive safety and, in particular, the use and choice of movable guards the central reservation crossing to traffic guidance systems, parking areas for vehicles of maintenance and emergency services, access to infrastructure areas, helicopter landing sites, lighting and fire-fighting items and emergency services.
The objective of the project is to develop basic elements for configuring the area before highway tunnels.
The design of approach zones to tunnels on motorways concerns numerous fields, the interests of tunnel users, tunnel operators and emergency services, especially fire brigade and police. The research results refer to a big number of particular measures. The important results are listed below.
– The research provides the bases to raise traffic safety in tunnel approaches by an optimal passive security. The recommended measures don't cause any additional costs.
– The research results allow an optimal layout of the tunnel approaches in favour of all involved services.
– The measures reduce traffic congestions during the preparation of tunnel maintenance.
– The presentation and judgement of different types of readily removable guard rails (or: safety barriers) and motor-driven lowering parapets on the central reserve allows an economic choice of the system.
– An overall view about the important elements reduces the costs of design.