Publication Detail
Exploratory Analysis of Motor Carrier Accident Risk and Daily Driving Patterns
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UCD-ITS-RR-90-10 Research Report |
Suggested Citation:
Jovanis, Paul P., Tetsuya Kaneko, Tzuoo-Ding Lin (1990) Exploratory Analysis of Motor Carrier Accident Risk and Daily Driving Patterns. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-90-10
Driving at different times of day within one day, and over several days, are associated with different levels of accident risk. Analysis of accident and non-accident data from a less than truckload carrier representing 6 months of operation in 1984 are used to explore changes in daily and multiday accident risk. Cluster analysis is used to extract a distinct pattern of driving over a seven day period from a sample of 1066 drivers (including those with accidents and non-accidents on the eighth day).
The analyses yielded clear interpretable driving patterns that could be associated with levels of relative accident risk. Higher risk was generally, but not exclusively, associated with extensive driving in the 2-3 days prior to the day of interest. The two patterns with the highest risk of an accident were those that contained heavy driving during the prior three days and consisted of driving from 3:00 pm to 3:00 am (pattern 1) and from 10:00 pm to 10:am (Pattern 8). The lowest risk was associated with driving from 8:00 pm to 6:00 am but with limited driving on the prior 3 days. Given the virtually limitless possible combinations of driving schedules, it is quite encouraging that interpretable distinct multiday patterns could be extracted from a data base of over 1000 observations.
Within each pattern, drivers experienced very similar duty hours: cumulative driving over the seven days ranged from 47 to 49 hours. Continuous driving (between mandatory 8 hours off-duty periods) ranged from 7.8 to 8.4 hours. Individual drivers also experienced a cycle of on-duty and off-duty time which ranged from 22.3 to 23 hours, closer to the 24 hour period that is desirable from the perspective of human performance theories.
These findings suggest that it is possible to identify and extract patterns of multiday driving and that these patterns are associated with different levels of accident risk. Additional empirical tests are suggested as future research along with development of refined accident risk models.
The analyses yielded clear interpretable driving patterns that could be associated with levels of relative accident risk. Higher risk was generally, but not exclusively, associated with extensive driving in the 2-3 days prior to the day of interest. The two patterns with the highest risk of an accident were those that contained heavy driving during the prior three days and consisted of driving from 3:00 pm to 3:00 am (pattern 1) and from 10:00 pm to 10:am (Pattern 8). The lowest risk was associated with driving from 8:00 pm to 6:00 am but with limited driving on the prior 3 days. Given the virtually limitless possible combinations of driving schedules, it is quite encouraging that interpretable distinct multiday patterns could be extracted from a data base of over 1000 observations.
Within each pattern, drivers experienced very similar duty hours: cumulative driving over the seven days ranged from 47 to 49 hours. Continuous driving (between mandatory 8 hours off-duty periods) ranged from 7.8 to 8.4 hours. Individual drivers also experienced a cycle of on-duty and off-duty time which ranged from 22.3 to 23 hours, closer to the 24 hour period that is desirable from the perspective of human performance theories.
These findings suggest that it is possible to identify and extract patterns of multiday driving and that these patterns are associated with different levels of accident risk. Additional empirical tests are suggested as future research along with development of refined accident risk models.
Refer to RP-91-27 (PubID 982) for a condensed version of this report, published in Transportation Research Record 1322