Emergency vehicle signals revised. Emergency signals (blue warning light and siren) can be used by vehicles of police, ambulance, and de fire brigade when they have to do an emergency task. The legislation on emergency signals is considered to be outdated, unclear, and incomplete on several points. Therefore the working group emergency signals (WOG) has proposed adjustments of the specifications and application rules for emergency signals. These are also based on a literature survey by TNO-HF in 1998. The Dutch Ministry of Interior Affairs (BZK) asked us to check these proposals and to compare them to the state of the art of technology, science, and the current practice and to come with proposals for legislation. A literature survey was performed on light and sound signals and the behavioural aspects of emergency signals. In addition, we interviewed emergency vehicles drivers. On basis of the results the WOG-report was assessed. During this verification we paid attention to elements such as visibility, recognizability, comprehensibility, and credibility of the emergency signals and also to the behaviour of the emergency vehicle drivers and the other road users. The main results of literature are as follows. For good visibility of the emergency vehicle for the car in front, the blue light at the front of the emergency vehicle should be located in the centre. Contour marking and a proper colour can improve the visibility and recognizability of vehicles. A cognitive task in the car (e.g. using the telephone) has a negative effect on visual perception. Listening to music in a car causes an extra reduction of the audibility of sirens, particularly for the elderly. The siren should consist of a two-tone horn (pitches of 375 and 500 Hz) with a sound level between 110 and 120 dBA and a broad frequency range with partial tones up to at least 5000 Hz. Alerting and localisation should be improved by using short on- and offsets. In the vicinity of an incident it is proposed to use yellow warning lights rather than blue warning lights. There are technical systems that switch the traffic lights automatically to green and informs other traffic when an emergency vehicle approaches. The interviews showed that drivers of emergency vehicles find the rules too rigid. Often they do not obey the rules because they want to arrive in time at the incident location. They nevertheless find that proper rules of behaviour are important. We recommend readjusting some of the proposals of the WOG. We propose to put the extra blue warning light in the front centre of the vehicle, to allow retroreflective striping, and to be careful with the use of alternating headlamps and green signal light. The specifications for sound signals have to be adapted at several points. The rules for the emergency vehicle drivers have to be clear and must be part of their professional training.(Author/publisher)
Samenvatting