The EDDIT project was designed to evaluate the use of ATT systems by elderly drivers with two main objectives: a) to see whether these systems could lead to an improvement in the mobility of older drivers; and b) to find out whether the use of such systems would have any effect on the safety of older drivers. The project tested six different ATT applications, examined two generic issues and also developed a training programma designed to enhance the use of and benefits from ATT for elderly drivers. The six applications tested were: 1) route guidance; 2) traffic information; 3) emergency alert; 4) reversing aid; 5) night vision; and 6) collision warning. The generic issues examined were a comparison of head-up display with on-dashboard display and an examination of the effects of size and complexity of symbolic guidance information. These two issues and the evaluation of two collision warning systems were carried out in driving simulators; all the other tests were carried out in cars on public or private roads. The elderly drivers who took part in the tests were found, in general, to have a positive attitude towards ATT and recognized its potential values. While the use of some of the systems had a limited effect on the driving safety performance of the drivers, such effects were mostly small in scale and certainly much smaller than the absolute variations in driving safety as measured between subjects. However systems that require a significant degree of attentional effort, such as the Carminat C1, rather than simple interrogative or message reading glances, were found to cause difficulties for drivers with resultant changes in driving speed and trajectory. The importance of making the task of using the ATT system as simple as possible was emphasized by the findings from the study into size and complexity of guidance information. This trial was carried out with a sample of younger as well as older drivers, and it was found that although both groups of drivers coped less well with the basic driving tasks when presented with increasingly complex information, there was also a relative change in performance between the two groups, with the elderly drivers performing relatively worse as complexity increased. On the positive side route guidance, vision enhancement and emergency alert systems were all found to be likely to be of assistance to elderly drivers. Route guidance would encourage the use of roads and routes with which they were not familiar and would encourage, on a modest scale, more use of the car. This is important because one of the observed effects of increasing age is a reluctance to venture onto 'new' routes and a concomitant closing down of travel horizons. Another common problem faced by elderly drivers is that of dealing with driving at night time, when both a loss of visual acuity and difficulty dealing with glare from on-coming traffic headlights cause problems. The two vision enhancement systems tested (near infrared and ultra-violet) both much improved the ability of elderly drivers to see road features and pedestrians and would encourage them not to stop driving simply because of darkness. The emergency alert system which provided a two-way voice channel between the driver and the control centre, as well as giving the centre an accurate location for the vehicle, very clearly met other needs of elderly drivers. In common with many disabled drivers and women driving alone, elderly drivers are worried about their personal safety. A system such as that tested by EDDIT provides a large measure of reassurance to the driver in the event of an accident or breakdown and, like the route guidance system, would encourage older drivers not to restrict their journeys to local areas with which they were very familiar. The reversing aids tested enabled elderly drivers to park more accurately within confined spaces and it appears probable that they would reduce the likelihood of a driver reversing into a moving object - such as a child. Although considered by most elderly drivers to be helpful, these systems do not seem likely to make any significant difference in the propensity to use the car. The driving simulator tests of collision warning were more difficult to assess in terms of possible effects on driving behaviour, if only because they were simulated as opposed to real driving situations. The results suggest that such systems could assist elderly drivers, especially at night time, but perhaps the most important conclusion was that the "safe gap" setting for the system needs to be tailored to the abilities of the individual driver, not set at a single, universal level. One other issue is worth emphasizing, since it was found to apply to all systems, and that is the value of audible as well as visual information. Whether the audible signal is simply a sound to warn the driver (as, for example, when reversing) or a spoken message (as in a route guidance system) the test results show that this is considered extremely helpful by elderly drivers. An audible signal tends to reduce the amount of time that the driver spends looking at the visual display and to lead to a more relaxed attitude towards driving. In general it is concluded that well-designed ATT systems can improve the mobility of elderly drivers and can do so without any deleterious effect on their driving safety.
Samenvatting