| 1. |
- af Wåhlberg, Anders, 1965-, et al.
(författare)
-
Absence behaviour as traffic crash predictor in bus drivers
- 2009
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 40:3, s. 197-201
-
Tidskriftsartikel (refereegranskat)abstract
- Problem Various indicators of health have been shown to be associated with traffic crash involvement. As general health is also related to absence from work, the latter variable may be more strongly related to crashes, especially for professional drivers. Method Bus driver absence from work was analyzed in association with their crash records. Two British samples and one Swedish sample were used. Results One of the British samples yielded fair correlations between crash record and absence, while for the other the effect was restricted to the first three months of driving. The Swedish data had effects in the expected direction but these were not significant. Discussion The use of an indirect, overall measurement of health, may be a viable method for predicting the traffic crash involvement for professional drivers, although replications are needed in larger samples and other populations. Impact on industry The use of absence records for the identification of at risk drivers would seem to be a simple and useful method for companies with major fleets, and it also shows the importance of promoting employee health and well being at work as a potential method of reducing the cost, not only of absenteeism, but also of crashes in company vehicles.
|
|
| 2. |
|
|
| 3. |
- af Wåhlberg, Anders, 1965-, et al.
(författare)
-
Culpable versus non-culpable traffic accidents; what is wrong with this picture?
- 2007
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 38:4, s. 453-459
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: It is often implicitly or explicitly assumed in traffic accident research that drivers with accidents designated as non-culpable are a random sample from the population. However, this assumption is dependent upon differences in the criterion used for culpability. If drivers are erroneously categorized by assuming randomness, results could be grossly misleading. Method: The assumption of randomness leads to two predictions: first, no correlation should exist between culpable and non-culpable crashes; and second, the accident groups should differ on the variables known to be associated with accidents, such as amount of driving experience. These predictions were tested in two samples of bus drivers. Results: It was found that in a sample with a harsh criterion (70% culpable accidents) for crash responsibility, the drivers with non-culpable accidents had the features expected, namely, they were more experienced for example, while in a sample with a lenient criterion (50 % culpable), this was not so. Discussion: It was concluded that similar studies to the present one would need to be undertaken to establish exactly what percentage of drivers in a given population should be assigned culpable accidents, and construct a criterion that yields this ratio. Otherwise, the theoretical assumptions of randomness and non-responsibility will probably be violated to some degree. Impact on Industry: Many estimates of risk of crash involvement may have been wrong. Given the potential for erroneous criteria, a number of studies may make invalid assumptions from their data.
|
|
| 4. |
- af Wåhlberg, Anders E.
(författare)
-
A reporting guide for studies on individual differences in traffic safety
- 2010
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 41:4, s. 381-383
-
Tidskriftsartikel (refereegranskat)abstract
- Problem: Studies on individual differences in traffic safety report differently on their methodologies, and use different statistics, and these are therefore difficult to compare and meta-analyze. Method: Based upon a previous, extensive review and meta-analysis of the traffic safety literature, several recommendations are made about what features of the methodology of studies on individual differences (including evaluations) in safety need to be reported to facilitate interpretation and meta-analysis. Similarly, some basic types of statistical values are recommended. Impact on Industry: The accumulation of knowledge about individual differences in traffic safety would be facilitated if scientific authors and journals adhered to these guidelines.
|
|
| 5. |
- af Wåhlberg, Anders E.
(författare)
-
Effects of passengers on bus driver celeration behavior and incident prediction
- 2007
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 38:1, s. 9-15
-
Tidskriftsartikel (refereegranskat)abstract
- Problem: Driver celeration (speed change) behavior of bus drivers has previously been found to predict their traffic incident involvement, but it has also been ascertained that the level of celeration is influenced by the number of passengers carried as well as other traffic density variables. This means that the individual level of celeration is not as well estimated as could be the case. Another hypothesized influence of the number of passengers is that of differential quality of measurements, where high passenger density cirrcumstances are supposed to yield better estimates of the individual driver component of celeration behavior. Method: Comparisons were made between different variants of the celeration as predictor of traffic incidents of bus drivers. The number of bus passengers was held constant, and cases identified by their number of passengers per kilometer during measurement were excluded (in 12 samples of repeated measurements). Results: After holding passengers constant, the correlations between celeration behavior and incident record increased very slightly. Also, the selective prediction of incident record of those drivers who had had many passengers when measured increased the correlations even more. Conclusions: The influence of traffic density variables like the number of passengers have little direct influence on the predictive power of celeration behavior, despite the impact upon absolute celeration level. Selective prediction on the other hand increased correlations substantially. This unusual effect was probably due to how the individual propensity for high or low celeration driving was affected by the number of stops made and general traffic density; differences between drivers in this respect were probably enhanced by the denser traffic, thus creating a better estimate of the theoretical celeration behavior parameter C. The new concept of selective prediction was discussed in terms of making estimates of the systematic differences in quality of the individual driver data.
|
|
| 6. |
- af Wåhlberg, Anders E.
(författare)
-
Re-education of young driving offenders : Effects on self-reports of driver behavior
- 2010
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 41:4, s. 331-338
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Offending drivers are often re-educated, but these courses have seldom been shown to have any safety effects. Method: An on-line improvement course for offending drivers below the age of 25 was evaluated with several driver inventories. Results: The drivers reported higher levels of aggression, stress, sensation seeking, drunk driving, and driving violations, six months after the course than before. However, these levels were lower than those of controls, indicating that the initially low levels for the education group were due to socially desirable responding, as measured by a lie scale, an effect that waned after the course. Discussion: The results can be interpreted as a positive effect of the education, although this conclusion is tentative and not in agreement with all effects in the data. Impact on industry: The results are in disagreement with previous evaluation studies using the same or similar instruments, and show the need to include controls for social desirability in self-report studies.
|
|
| 7. |
- af Wåhlberg, Anders E.
(författare)
-
The accident-exposure association : self-reported versus recorded collisions
- 2011
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 42:2, s. 143-146
-
Tidskriftsartikel (refereegranskat)abstract
- Problem: It has been claimed that exposure to risk of road traffic accidents (usually conceptualized as mileage) is curvilinearly associated with crashes (i.e., the increase in number of crashes decreases with increased mileage). However, this effect has been criticized as mainly an artifact of self-reported data. Method: To test the proposition that self-reported accidents create part of the curvilinearity in data by under-reporting by high-accident drivers, self-reported and recorded collisions were plotted against hours of driving for bus drivers. Results: It was found that the recorded data differed from self-reported information at the high end of exposure, and had a more linear association with the exposure measure as compared to the self-reported data, thus supporting the hypothesis. Discussion: Part of the previously reported curvilinearity between accidents and exposure is apparently due to biased methods. Also, the interpretation of curvilinearity as an effect of exposure upon accidents was criticized as unfounded, as the causality may just as well go the other way. Impact on industry: The question of how exposure associates with crash involvement is far from resolved, and everyone who uses an exposure metric (mileage, time, induced) should be careful to investigate the exact properties of their variable before using it.
|
|
| 8. |
- af Wåhlberg, Anders, 1965-
(författare)
-
Social desirability effects in driver behavior inventories
- 2010
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 41:2, s. 99-106
-
Tidskriftsartikel (refereegranskat)abstract
- Problem: The use of lie scales to control for common method variance in driver behavior inventories has been very limited. Given that such questionnaires often use self-reported safety variables as criteria, and have social implications, the risk of artefactual associations is high. Method: A questionnaire containing scales from several well known driver inventories that have been claimed to predict traffic accident involvement was distributed three times to a group of young drivers in a driver education program, as well as a random group twice. The Driver Impression Management scale (DIM) was used to control for socially desirable responding. Results: For all behavior scales, the correlation with the DIM scale was substantial. If a scale correlated with self-reported crashes, the amount of predictive power was more than halved when social desirability was controlled for. Results were similar for both samples and all waves. The predictive power of the behavior scales was not increased when values were averaged over questionnaire waves, as should have been the case if the measurement and predictive power were valid. Results were similar for self-reported penalty points. The present results indicate that even the most well-known and accepted psychometric scales used in driver research are susceptible to social desirability bias. Discussion: As social desirability is only one of a number of common method variance mechanisms that can create artefactual associations, and the great popularity of the self-report methodology, the problem for traffic research is grave. Impact on industry: Organizations that fund traffic safety research need to re-evaluate their policies regarding what methods are acceptable. The use of self-reported independent and dependent variables can lead to directly misleading results, with negative effects on traffic safety.
|
|
| 9. |
|
|
| 10. |
- af Wåhlberg, Anders
(författare)
-
The relation of non-culpable traffic incidents to bus drivers' celeration behavior
- 2008
-
Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375 .- 1879-1247. ; 39:1, s. 41-46
-
Tidskriftsartikel (refereegranskat)abstract
- Problem: The driver celeration behavior theory predicts that celerations are associated with incidents for which the driver has some responsibility in causing, but not other incidents. Method: The hypothesis was tested in 25 samples of repeated measurements of bus drivers' celeration behavior against their incidents for two years. Results: The results confirmed the prediction; in 18 samples, the correlation for culpable incidents only was higher than for all incidents, despite the higher means of the latter. Non-culpable incidents had correlations close to zero with celeration. Discussion: It was pointed out that most individual crash prediction studies have not made this differentiation, and thus probably yielded underestimates of the associations sought, although the effect is not strong, due to non-culpable accident involvements being few (less than a third of the total). The methods for correct identification of culpable incident involvements were discussed.
|
|
