Travelling Speed and the Risk of Crash Involvement: The South Australian Experience (original) (raw)
Related papers
Travelling Speed and the Risk of Crash Involvement: Volume 1: Findings
1997
The relationship between free travelling speed and the risk of involvement in a casualty crash in a 60 km/h speed limit zone was quantified using a case control study design. The 151 case vehicles were passenger cars involved in crashes in the Adelaide metropolitan area which were investigated at the scene by the NHMRC Road Accident Research Unit at Adelaide University and reconstructed using the latest computer aided crash reconstruction techniques. The 604 control vehicles were passenger cars matched to the cases by location, direction of travel, time of day, and day of week and their speeds were measured with a laser speed gun. It was found that the risk of involvement in a casualty crash doubled with each 5 km/h increase in free travelling speed above 60 km/h. Hypothetical speed reductions applied to the case vehicles indicated large potential safety benefits from even small reductions in travelling speed, particularly on arterial roads. (a)
Travelling Speed and the Risk of Crash Involvement on Rural Roads
2001
The relationship between free travelling speed and the risk of involvement in a casualty crash in 80 km/h or greater speed limit zones in rural South Australia was quantified using a case control study design. The crashes involving the 83 case passenger vehicles were investigated at the scene by the Road Accident Research Unit and reconstructed using the latest computer aided crash reconstruction techniques. The 830 control passenger vehicles were matched to the cases by location, direction of travel, time of day, and day of week, and their speeds were measured with a laser speed gun. It was found that the risk of involvement in a casualty crash increased more than exponentially with increasing free travelling speed above the mean traffic speed and that travelling speeds below the mean traffic speed were associated with a lower risk of being involved in a casualty crash. The effect of hypothetical speed reductions on all of the 167 crashes investigated indicated large potential safe...
2007
Generalised linear models of road trauma outcomes have been found to be a powerful way of representing the trends and variations over time and to explain the effects of influential factors such as countermeasure initiatives. This report covers their application to monthly casualty crash frequencies and injury severity outcomes in Victoria during 1998 to 2003. During 2000 to 2002, the mobile speed camera program in Victoria was changed by introducing "flashless" camera operations during daytime and other modifications to make the enforcement more covert and unpredictable, increasing the targeted camera operating hours from 4200 to 6000 hours per month, and reducing the speeding offence detection threshold in three stages. In December 2002, the thresholds for penalties applying to different levels of speeding offence were generally reduced by 5 km/h. Associated with the speed enforcement initiatives was a program of speed-related advertising known as the "Wipe Off 5" campaign launched in early August 2001 without specific reference to the enforcement changes. A subsequent announcement took place in late November 2001 specifically mentioning the more covert speed camera operations as well as the increase in camera hours. A third announcement took place in the print media at the end of March 2002, emphasising that the former 9 km/h speeding tolerance no longer applied. As well as the enforcement changes, the statistical models included the reduced urban speed limit in January 2001, the penalty restructure, the speed-related advertising and the announcements, plus the impact of the fixed speed camera controversy that arose in late 2003. The study concluded that generalised linear modelling of crash outcomes as a function of potential explanatory factors needs realistic assumptions to be made about viable functional forms connecting a measure of each factor and the outcomes. The assumed functional form of the relationship between monthly speed camera hours and road trauma appears to represent this relationship well. There is doubt that the flashless speed camera initiative and the enforcement threshold reductions have been adequately represented in the monthly crash outcome models. It was concluded that the effect of these initiatives on crash outcomes is unknown at this stage. The assumed functional form of the relationship between monthly speed-related advertising levels and road trauma appears to represent this relationship well. The speed-related television advertising had a statistically significant association with a decrease in monthly casualty crash frequencies during times of increased advertising levels. In general the relationships connecting speed camera hours and levels of speed-related advertising with road trauma reductions in Victoria confirmed previous research on the effectiveness of these road safety programs as operated in the State.
Generalised linear models of road trauma outcomes have been found to be a powerful way of representing the trends and variations over time and to explain the effects of influential factors such as countermeasure initiatives. This report covers their application to monthly casualty crash frequencies and injury severity outcomes in Victoria during 1998. During 2000, the mobile speed camera program in Victoria was changed by introducing "flashless" camera operations during daytime and other modifications to make the enforcement more covert and unpredictable, increasing the targeted camera operating hours from 4200 to 6000 hours per month, and reducing the speeding offence detection threshold in three stages. In December 2002, the thresholds for penalties applying to different levels of speeding offence were generally reduced by 5 km/h. Associated with the speed enforcement initiatives was a program of speed-related advertising known as the "Wipe Off 5" campaign launched in early August 2001 without specific reference to the enforcement changes. A subsequent announcement took place in late November 2001 specifically mentioning the more covert speed camera operations as well as the increase in camera hours. A third announcement took place in the print media at the end of March 2002, emphasising that the former 9 km/h speeding tolerance no longer applied. As well as the enforcement changes, the statistical models included the reduced urban speed limit in January 2001, the penalty restructure, the speed-related advertising and the announcements, plus the impact of the fixed speed camera controversy that arose in late 2003.
Driving speed and the risk of road crashes: A review
Accident Analysis & Prevention, 2006
Driving speed is an important factor in road safety. Speed not only affects the severity of a crash, but is also related to the risk of being involved in a crash. This paper discusses the most important empirical studies into speed and crash rate with an emphasis on the more recent studies. The majority of these studies looked at absolute speed, either at individual vehicle level or at road section level. Respectively, they found evidence for an exponential function and a power function between speed and crash rate. Both types of studies found evidence that crash rate increases faster with an increase in speed on minor roads than on major roads. At a more detailed level, lane width, junction density, and traffic flow were found to interact with the speed-crash rate relation. Other studies looked at speed dispersion and found evidence that this is also an important factor in determining crash rate. Larger differences in speed between vehicles are related to a higher crash rate. Without exception, a vehicle that moved (much) faster than other traffic around it, had a higher crash rate. With regard to the rate of a (much) slower moving vehicle, the evidence is inconclusive.
Death and Injury from Motor Vehicle CrashesA Tale of Two Countries
American Journal of Preventive Medicine, 2005
To determine why road deaths dropped by 33.9% in the United Kingdom, compared to 6.5% in the United States, between 1990 and 1999. Methods: Deaths per billion vehicle kilometers traveled (D/BVKM), and case fatality rates (CFR) in the United States and the United Kingdom were tracked. Time trends in CFR can be used to track the direct effects of speed of impact. CFR is a crash-phase outcome that is independent of exposure, and varies approximately to the fourth power of the speed of crash impact. Joinpoint regression analysis was used to analyze changes in time trends of CFR. Results: In the 1990s, the decrease in deaths in the United Kingdom was attributable mostly to the 29.6% drop in the CFR. In the United States, the CFR dropped by only 6.6%. The United Kingdom introduced speed cameras and an array of speed-calming measures. By contrast, in the United States, use of speed cameras was extremely rare, and speed limits and speeds increased in 32 of the 50 states, mostly in 1995 and 1996, after which CFR actually rose (p Ͻ.0001). Intercountry differences in time trends in seat belt use, trauma care, vehicle kilometers traveled, congestion, and driving under the influence of alcohol (DUI), along with massive increase in use of higher-risk sports utility vehicles in the United States, did not account for the contrasting trends in deaths through the 1990s. But increases in DUI in the United States after 1997 may have contributed to increases in speed-related crashes. Conclusions: The reductions in CFR, probably from small drops in speed of impact account for the disproportionately greater drop in death tolls in the United Kingdom compared to the United States. The temporal fit between drops in CFR and deaths following the introduction of speed cameras in the United Kingdom and increases in speed (speed creep), CFR, and deaths in the United States following raised speed limits suggests that diverging changes in speeds of impact accounted mainly for these changes. Use of D/BVKM to correct for exposure concealed the lack of progress after 1990 in the United States, since falling time trends in D/BVKM reflect increases in congestion. If the United States had implemented United Kingdom-type speed control policies and not raised speed limits, there would have been an estimated 6500 to 10,000 (ϳ16% to 25%) fewer road deaths per year during the period following speed-limit increases (1996 to 1999), including many DUI-related deaths. Reductions of up to 50% are now achievable based on newer population-wide strategies for speed control.
Overall impact of speed-related initiatives and factors on crash outcomes
Annual proceedings / Association for the Advancement of Automotive Medicine. Association for the Advancement of Automotive Medicine, 2007
From December 2000 until July 2002 a package of speed-related initiatives and factors took place in Victoria, Australia. The broad aim of this study was to evaluate the overall impact of the package on crash outcomes. Monthly crash counts and injury severity proportions were assessed using Poisson and logistic regression models respectively. The model measured the overall effect of the package after adjusting as far as possible for non-speed road safety initiatives and socio-economic factors. The speed-related package was associated with statistically significant estimated reductions in casualty crashes and suggested reductions in injury severity with trends towards increased reductions over time. From December 2000 until July 2002, three new speed enforcement initiatives were implemented in Victoria, Australia. These initiatives were introduced in stages and involved the following key components: More covert operations of mobile speed cameras, including flash-less operations; 50% i...
Risk factors for fatal crashes in rural Australia
Accident Analysis & Prevention, 2011
This paper presents findings from the Rural and Remote Road Safety Study, conducted in Queensland, Australia, from March 2004 till June 2007, and compares fatal crashes and non-fatal but serious crashes in respect of their environmental, vehicle and operator factors. During the study period there were 613 non-fatal crashes resulting in 684 hospitalised casualties and 119 fatal crashes resulting in 130 fatalities. Additional information from police sources was available on 103 fatal and 309 non-fatal serious crashes. Over three quarters of both fatal and hospitalised casualties were male and the median age in both groups was 34 years. Fatal crashes were more likely to involve speed, alcohol and violations of road rules and fatal crash victims were 2½ times more likely to be unrestrained inside the vehicle than non-fatal casualties, consistent with current international evidence. After controlling for human factors, vehicle and road conditions made a minimal contribution to the seriousness of the crash outcome. Targeted interventions to prevent fatalities on rural and remote roads should focus on reducing speed and drink driving and promoting seatbelt wearing.
Travelling Speed and the Risk of Crash Involvement Volume 2 - Case and Reconstruction Details
1997
Volume 2 of this Report "Case and Reconstruction Details" contains detailed information on each individual case and explains the method of analysis used in the reconstruction process. It is not necessary to view Volume 2 in order to understand the general method and results of the study. However, it may be of interest to researchers wishing to examine the study in detail or to conduct another similar study. In light of this, Volume 2 is being made available only in electronic format on the Internet (along with the electronic version of Volume 1