Regular fatigue-o-meter testing reduces accidents


Driver vigilance during advanced driver training

In cooperation with Subaru (SA) the writer had the opportunity recently to assess the reaction times of drivers who were being trained in advanced driver skills at the Gerotek center, as well as the Swartkops racetrack in     Pretoria   .

The objectives of the research project were to:

Assess the degree to which the Fatigue-o-meter could distinguish the changes in vigilance of these drivers as the day progressed and they were exposed to physically and mentally taxing procedures. Determine the correlation between objective measures of driver ability and the various ratings of vigilance as recorded during the day.


The agenda during the day's training was as follows:

The drivers met at 8h00 for a general theoretical lecture and orientation. The first activity of the day consisted of skidpan exercises. These activities were relatively mild and consisted of wet road turns, slides and skid control. This session ended in a precision and speed trial during which the drivers had to complete a specified circuit on the skidpan, making their way through obstacles. Driver times were recorded for this session and used as objective standard of general ability and skill.

The drivers were given lunch and relaxed for 40 minutes.

The final session consisted out of grueling high speed (+- 160kms/hr) circuits at Swartkops. Drivers were expected to learn how to handle their vehicles at high speed and generally completed 3 to 6 circuits around the 1.3 km track. Drivers were visibly tired and mentally taxed by this activity.

The fatigue-o-meter tests were done at the end of each of the above stages. Reaction times were corrected by a constant for errors. The following results were obtained:

Reaction times over all four stages.

Correlation between reaction times at each stage and the objective test of precision conducted at stage 2.

The graph below ( Graph 1) illustrates the vigilance of the drivers at each stage:

Graph 1: Driver reaction times on the Fatigue-o-meter:

As can be seen on the above graph, the drivers started relatively slow and were probably still waking up (Monday morning) at the start of the day. At the end of the skid pan exercise they reached their baseline level of vigilance and were relatively stable.

Lunch brought about an improvement of 20%. The afternoon session showed a dramatic deterioration of 50% from their lunch time response speeds and clearly indicates the effect of extended strain and road tension on driver vigilance.

Graph 2: Correlation between reaction times and objective measure of accuracy:


The above graph shows the correlation between reaction times and the measure of individual driving precision recorded at the end of the skid pan exercise. This line of exponentially increasing correlations indicates that two factors are at work:The driver's individual level of vigilance is constantly and positively correlated with driving precision.

The driver's individual deterioration in vigilance tends to produce a variable influence on precision.

General comments:

The above data adds practical credence to the Fatigue-o-meter ability to determine driver vigilance deterioration accurately and suggests that mild levels of negative driver vigilance can be restored (+- 20%) by rest and relaxation. The correlation analysis data suggests that the vigilance level of drivers (present as well as applicants) may be used to determine general driver precision. It furthermore indicates that drivers who are cautioned for lack of vigilance, may more often lack precision and vehicle control and may be more inclined to have driving accidents.