It is quite difficult to drive in a road tunnel due to the lack of references. This fact makes it difficult to know at any time the mandatory safety minimum distance. This situation favours keeping distances less than the braking distance.
The main objective of this project was to reach the maximum safety levels in road tunnels by using preventative actions like lights and radio-frequency signals. Besides, the existing preventative actions are studied for adapting them for disabled people.
Another objective of this project after completion of these works was to undertake tests of the lights and the radio-frequency emitter installed in the tunnel.
The phases of this project were:
- identification of the problem;
- requirements for the best solution (visibility, ease of use, practicality, universality);
- design of the system;
After the identification of the problem, the system should provide the minimum distance established in the General Traffic Regulation. Additional requirements are also specified (visibility, easy to use, practical and universal):
- The system gives a good visibility whatever the light condition of the tunnel. To do this it would be necessary to use light pilots in total or partial composition of distance element;
- The system indicates the information in a very easy way in such a way that at any moment the driver can notice and understand the information without being distracted from driving. The location of the information has been studied in order to optimise perception;
- The number of marks has been studied in order to establish minimum distance. This indicated distance by the system will be defined by installation of three marks or distance elements fitted in the pavement and on the central edge of each lane;
- The system has to be universal. This means that it is designed to be installed in any tunnel. Thickness of the elements is always less than the pavement. Electrical design is dimensioned from transformation centres present in every tunnel.
The design of this system has an easy, quick and economic way to put it up, using elements readily available in the trade market.
The project detailed some actions for improving prevention for avoiding possible infrequent incidents in tunnels. This system consists of placing a line of lights on both sides of the platform to helping drivers maintain a safe distance from the vehicle in front.
A prototype of the system has been deployed. Likewise some elements of radio-frequency are placed inside the tunnel, that will be able to inform the driver by radio about the recommended speed or other preventative measures, as well as information on evacuation. Also the informative signs about safety measures will be made suitable for disabled people.
The conclusions extracted in the first part of the project are:
- The system is oriented to help drivers to calculate in an easy and quick way the safety distance that the vehicle should maintain with the preceding vehicle;
- The safe inter-vehicle distance is defined using distance marks fitted in the pavement;
- The distance marks are located on the central edge of each lane;
- The distance marking will utilise existing elements in the trade market. Pilot lights will be used as a visual reinforcement.
The deployed system will:
- Reduce accidents in tunnels;
- Improve the traffic conditions;
- Be able to adapt to several kinds of tunnel infrastructure.
The results have been deployed in several guidelines and formulas. These have been used for the installation of the system in any tunnel, whatever its characteristics.