Results from this project show that an audio warning inside the car to drivers approaching road work zones had a considerable effect on speed reduction and thus showed a road safety potential from which both road workers and road users can benefit. The project has been carried out to find methods that effectively decrease drivers’ speed at road work sites through real-time audio warnings. A practical evaluation of the potential use of audio warnings at roadwork sites was carried out in a VTI driver simulator. Results from the initial literature review show that the characteristics of a successful audio alert are: female voice, direct and informative messages, an interaction between semantics and acoustics, successively increased intensity, and dimming of secondary audio distractions. The results of the simulation tests show in broad strokes that drivers reduced their average speed from 110 to 100 km/h when driving through the road work without audio warning and from 110 to 88 km/h when they received audio warning. The effect is significant and the average decrease is estimated to be 9–17 km/h greater with audio warning than without. Furthermore, there was still a small effect (0.5–3.3 km/h) left of the audio alert after the road works. The subjects were asked how an audio warning should be designed, the drivers suggested that the sound warning should come before the road work is seen. Most of the drivers were in favour of an audio alert, but there were different views on whether they themselves would use such a feature or not, if it was eligible, for example, in a GPS or on their radio. It was also suggested that an application can be developed for mobile phone use. In conclusion, an audio warning inside the car to drivers approaching road work zones had a considerable effect on speed reduction and therefore the researchers suggest future studies in order to further develop the method for such audio warnings. (Author/publisher)
Abstract