Driver discomfort in vehicle seats: effect of changing road conditions and seat foam composition

Discomfort in vehicle seats is a multi-factorial problem with contributions occurring from effects of sitting duration, seat design, and the dynamic environment to which the occupant is exposed. This paper reports laboratory studies investigating the extent to which reports of discomfort are affected by vibration commencing or ceasing, and whether methods of assessment are sensitive enough to detect small changes in foam composition. Study 1 measured discomfort ratings for two conditions of 60 minutes each, comprising 30 minutes of vibration exposure followed by 30 minutes of static sitting in a car seat, and vice-versa. Study 2 measured discomfort ratings for three conditions over a period of 40 minutes each, whilst participants were sitting in one of two car seat compositions, and either exposed to vibration or not. In both studies participants operated a driving simulator. It is shown that exposure to vibration increases the rate of discomfort onset in comparison to periods of static sitting. When vibration stopped, there was an acute improvement in comfort but discomfort did not drop to the levels reported by those who had been unexposed. When vibration started after 30 minutes of static sitting, there was an acute increase in discomfort but not to the levels reported by those who had been exposed to 30 minutes of vibration. After 40 minutes of continuous exposure it was possible to detect significant differences in overall discomfort between the two seat compositions, although trends could be observed in less time

Effect of long term driving on driver discomfort and its relationship with seat fidgets and movements (SFMs)

Discomfort in vehicle seats is a multifactorial problem with large increases in discomfort occurring during extended duration driving. Due to the nature of driver discomfort, previous research has found it difficult to accurately quantify long term driver discomfort via the use of objective measures. This paper reports a laboratory study that investigates a novel objective measure of long term driver discomfort and its correlation with subjective discomfort ratings. Analysis of driver’s seat fidgets and movements was conducted over the duration of a 140 minute drive on a driving simulator in addition to collecting subjective ratings of discomfort. It is shown that as subjects’ subjective discomfort increases, the frequency of subjects’ seat fidgets and movements increases congruently. A large correlation is observed between the subjective and objective measures of driver discomfort and provides the opportunity for long term discomfort evaluations to be made via remote monitoring; removing the need for subjective assessment

Improving long term driving comfort by taking breaks - how break activity affects effectiveness

During long duration journeys, drivers are encouraged to take regular breaks. The benefits of breaks have been documented for safety; breaks may also be beneficial for comfort. The activity undertaken during a break may influence its effectiveness. Volunteers completed 3 journeys on a driving simulator. Each 130 min journey included a 10 min break after the first hour. During the break volunteers either stayed seated, left the simulator and sat in an adjacent room, or took a walk on a treadmill. The results show a reduction in driver discomfort during the break for all 3 conditions, but the effectiveness of the break was dependent on activity undertaken. Remaining seated in the vehicle provided some improvement in comfort, but more was experienced after leaving the simulator and sitting in an adjacent room. The most effective break occurred when the driver walked for 10 min on a treadmill. The benefits from taking a break continued until the end of the study (after a further hour of driving), such that comfort remained the best after taking a walk and worst for those who remained seated. It is concluded that taking a break and taking a walk is an effective method for relieving driving discomfort

Driver discomfort in vehicle seats – Effect of changing road conditions and seat foam composition

This article was published in the journal Applied Ergonomics [© Elsevier] and the definitive version is available at: http://dx.doi.org/10.1016/j.apergo.2015.03.010Discomfort in vehicle seats is a multi-factorial problem with contributions occurring from effects of sitting duration, seat design, and the dynamic environment to which the occupant is exposed. This paper reports laboratory studies investigating the extent to which reports of discomfort are affected by vibration commencing or ceasing, and whether methods of assessment are sensitive enough to detect small changes in foam composition. Study 1 measured discomfort ratings for two conditions of 60 minutes each, comprising 30 minutes of vibration exposure followed by 30 minutes of static sitting in a car seat, and vice-versa. Study 2 measured discomfort ratings for three conditions over a period of 40 minutes each, whilst participants were sitting in one of two car seat compositions, and either exposed to vibration or not. In both studies participants operated a driving simulator. It is shown that exposure to vibration increases the rate of discomfort onset in comparison to periods of static sitting. When vibration stopped, there was an acute improvement in comfort but discomfort did not drop to the levels reported by those who had been unexposed. When vibration started after 30 minutes of static sitting, there was an acute increase in discomfort but not to the levels reported by those who had been exposed to 30 minutes of vibration. After 40 minutes of continuous exposure it was possible to detect significant differences in overall discomfort between the two seat compositions, although trends could be observed in less time