Accident; analysis and prevention
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Comparative Study
Comparison of risk factors for cervical spine, head, serious, and fatal injury in rollover crashes.
Previous epidemiological studies of rollover crashes have focused primarily on serious and fatal injuries in general, while rollover crash testing has focused almost exclusively on cervical spine injury. The purpose of this study was to examine and compare the risk factors for cervical spine, head, serious, and fatal injury in real world rollover crashes. Rollover crashes from 1995-2008 in the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS) were investigated. ⋯ Greater roof crush was associated with a higher rate of fatal and cervical spine injury (p<0.05). Vehicle type, occupant height, and occupant gender had inconsistent and generally non-significant effects on injury. This study demonstrates both common and unique risk factors for different types of injuries in rollover crashes.
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This study compares the safety of bicyclists riding on bicycle boulevards to those riding on parallel arterial routes in Berkeley, California. Literature on the impact of motor vehicle traffic characteristics on cyclist safety shows that high motor vehicle speeds and volumes and the presence of heavy vehicles are all detrimental to cyclist safety. This suggests that cyclists may be safer on side streets than on busy arterials. ⋯ The difference in collision rate is highly statistically significant, unlikely to be caused by any bias in the collision and count data, and cannot be easily explained away by self-selection or safety in numbers. Though the used dataset is limited and the study design is correlational, this study provides some evidence that Berkeley's bicycle boulevards are safer for cyclists than its parallel arterial routes. The results may be suggestive that, more generally, properly implemented bicycle boulevards can provide cyclists with a safer alternative to riding on arterials.
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Deceleration lanes are important because they help drivers transition from high-speed lanes to low-speed ramps. Although they are designed to allow vehicles to depart the freeway safely and efficiently, many studies report high accident rates on exit ramps with the highest percentage of crashes taking place in deceleration lanes. This paper describes the results of a driving simulator study that focused on driving performance while approaching a divergence area and decelerating during the exiting maneuver. ⋯ Moreover, speeds recorded at the end of the deceleration lane exceed those for which the ramp's curves are designed; this creates risky driving conditions that could explain the high crash rates found in studies of exit ramps. Finally, statistical analyses demonstrate significant influences of traffic volume on some aspects of exiting drivers' performance: lower traffic volume results in elevated exiting speed and deceleration, and diverging drivers begin to decelerate earlier along the main lane when traffic volume is low. However, speeds at the end of the deceleration lane and the site of lane changing are not significantly influenced by traffic volume.
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A Stated Preference survey of speed choice on Norwegian rural roads with 80 km/h speed limit was made by the roadside in order to determine which factors most strongly influence this choice. The aim was to study deliberate speeding to identify any correlations between speed choice and (1) the drivers' perception of the level of police enforcement, (2) penalties for speeding and (3) the speed choice of the other drivers on the road. Drivers were asked about their perception of these variables before being presented to nine hypothetical situations for which they were asked about the most likely speed to choose. ⋯ Drivers made bad guesses when estimating the level of enforcement, but had more realistic views of the sanctions given for speeding, as well as the general speed levels. The largest speed reducing effects on individual speed choice were found by either making most other drivers on the road reduce their speed, or by substantially increasing enforcement. Stricter sanctions seem to affect the speed choice only marginally.