Diseases, consumption of medicines and responsibility for a road crash: a case-control study

The role of medical conditions in crashes is a topic of public debate. Some studies suggest that there has been a reduction in road traffic crashes subsequent to the medical restrictions introduced on drivers with medical deficiencies. As in today's society the car is an important factor for independence and socialization, it seems important to consider whether diseases or consumption of drugs increase the risk of causing a road crash in comparison to well-known major crash risk factors. A case-control study was conducted (733 injured drivers). The cases were subjects who were partly or totally responsible for their crash. The 304 controls were the non-responsible drivers. Diseases and medicine consumption were analyzed using logistic regression models. Cases were characterized by a higher percentage of young men. They were more frequently affected by fatigue, as were subjects who had consumed alcohol. A higher risk in subjects suffering from hypertension is observed (adjusted odds ratio [adjOR]=3.82; 95%CI=[1.42-10.24]). An association between antidepressant consumption and responsibility appeared (adjOR=3.61; 95%CI=[1.30-10.03]). CONCLUSION: Medical factors associated with responsibility were arterial hypertension and antidepressant consumption. Other medical conditions do not seem to play a preponderant role comparing to individual behaviours.     

Dominant role of drivers’ attitude in prevention of road traffic crashes: A study on knowledge,attitude, and practice of drivers in Iran

Objective

Evaluating the relation between Iranian drivers’ knowledge, attitude, and practice (KAP) regarding traffic regulations, and their deterministic effect on road traffic crashes (RTCs).

Setting

Two cities of Tehran and Zahedan, Iran.

Methods

A cross-sectional study was designed. Using a simplified cluster sampling design, 2200 motor vehicle drivers including 1200 in Tehran and 1000 in Zahedan were selected. Sixty locations in Tehran and 50 in Zahedan were chosen. In each pre-identified location, 20 adult drivers were approached consecutively. A questionnaire developed by researchers was filled by each participant. The questionnaire had four sections including items assessing the demographics, knowledge, attitude and practice of drivers toward traffic regulations. Logistic regression analysis was used to evaluate the relationship between the RTCs and KAP variables.

Results

The study sample consisted of 619 (28.1%) occupational and 1580 (71.8%) private drivers. Among them, 86.4% were male. The median age was 33.6 ± 10.83. Drivers in Tehran and Zahedan had no significant differences between their mean scores of KAP items of the questionnaire. Higher knowledge, safer attitude, and safer practice were associated with a decreased number of RTC. After adjusting for possible confounders, increase of one standard deviation in attitude and practice scores (but not knowledge) resulted in 26.4% and 18.5% decrease in RTC, respectively. Finally, considering knowledge, attitude and practice of drivers in one model to assess their mutual effect, it was shown that only attitude is significantly associated with a decrease of RTC (OR = 0.76, P = 0.007).

Conclusion

Increase in attitude and practice accompanied with decreased number of RTCs in Iranian drivers. Specifically, drivers’ attitude had the crucial effect. It is not knowledge and standard traffic education; rather it is how such education is registered as an attitude that translates what is being learned into actions. Without safer attitude, even safer self-reported practice will not result in lower RTCs.     

Road traffic injury incidence and crash characteristics in Dar es Salaam: A population based study

Road traffic injuries (RTI) are a public health threat and a major source of disability in developing countries. A population-based analysis of RTIs in a testimonially high-risk area of Dar es Salaam, the largest city in the East African country of Tanzania, was carried out with the goal of establishing an RTI incidence and to identify RTI characteristics that may be used for a targeted injury prevention program in these communities.     

Road traffic accidents in the United Arab Emirates: trends of morbidity and mortality during 1977-1998

High rates of serious road traffic accidents (RTAs) have been reported for several Arabian Gulf countries, including the United Arab Emirates (UAE). in recent years. This study aims to describe quantitatively the morbidity and mortality from RTAs in the UAE, to identify their trends during the period 1977-1998, to compare the results with those of developed countries, and to evaluate the information available on possible causes with a view to identifying the most useful direction for future research. Data were obtained from UAE's police and health sources and, for international comparison, from WHO Statistics reports and the published literature. Overall and cause-specific fatality and injury rates of RTAs were calculated. Estimates of trends were achieved by using linear regression. The characteristics of road users injured or killed were also analysed. The results revealed that during the period 1977-1998, the rates of RTAs per 100,000 population and per 100,000 motor vehicles declined in the UAE by a trend component of -56.3 (P < 0.001: R2 = 0.69) and -521.8 (P<0.001; R2=0.92), respectively. RTA fatality and injury rates based on the same denominators also declined by -1.1 (P<0.001; R2 = 0.56) and -13.3 (P < 0.001; R2 = 0.47); and by -3.8 (P < 0.02; R2 = 0.23) and - 90.0 (P < 0.001; R2 = 0.59), respectively. Paradoxically, however, except for a short period (1977-1985), a steady increase in the risk of injury and death in each RTA accompanied these declines. Between 1985 and 1998 the severity rate (the ratio of fatalities and injuries per 1,000 RTAs) more than tripled in the UAE. The UAE's rates were high when compared with a number of selected countries. The cause for the increasing severity of RTAs is not clear but the most likely cause could lie in speeding, careless driving, the changing vehicle mix on the roads and the standard of immediate care available for victims. Further investigation is essential and will require close collaboration between police and health authorities.     

The economic costs of road traffic crashes: Australia, states and territories

In this paper, we obtain detailed data on road traffic crash (RTC) casualties, by severity, for each of the eight state and territory jurisdictions for Australia and use these to estimate and compare the economic impact of RTCs across these regions. We show that the annual cost of RTCs in Australia, in 2003, was approximately $17b, which is approximately 2.3% of the Gross Domestic Product (GDP). Importantly, though, there is remarkable intra-national variation in the incident rates of RTCs in Australia and costs range from approximately 0.62 to 3.63% of Gross State Product (GSP). The paper makes two fundamental contributions: (i) it provides a detailed breakdown of estimated RTC casualties, by state and territory regions in Australia, and (ii) it presents the first sub-national breakdown of RTC costs for Australia. We trust that these contributions will assist policy-makers to understand sub-national variations in the road toll better and will encourage further research on the causes of the marked differences between RTC outcomes across the states and territories of Australia.     

Fatal crash involvement of unlicensed young drivers: County level differences according to material deprivation and urbanicity in the United States

Objectives

This study assessed the association between county level material deprivation and urbanization with fatal road traffic crashes involving young unlicensed drivers in the United States (US).

Background

Road traffic crashes have been positively associated with area deprivation and low population density but thus far few studies have been concerned specifically with young drivers, especially those that are unlicensed.

Methods

A county material deprivation index was derived from the Townsend Material Deprivation Index, with variables extracted from the US Census (2000). An urbanicity scale was adapted from the US Department of Agriculture's Rural–Urban Continuum Codes (2003). Data on fatal crashes involving a young unlicensed driver during a seven-year period (2000–2006; n = 3059) were extracted from the Fatality Analysis Reporting System. The effect of deprivation and urbanicity on the odds of the occurrence of at least one fatal crash at the county level was modeled by conditional and unconditional logistic regression.

Results

The conditional model found a positive association between material deprivation and a fatal crash involving a young unlicensed driver (OR = 1.19, 95% CI 1.17, 1.21). The interaction between urbanicity and material deprivation was negatively associated in suburban counties for fatal crashes (OR = 0.92, 95% CI 0.90, 0.95).

Conclusions

An association with material deprivation and the likelihood of a fatal crash involving a young unlicensed driver is a new finding. It can be used to inform specific county-level interventions and promote state licensing policies to provide equity in young people's mobility regardless of where they live.     

Road crash involvement and professional status: a prospective study using the French Gazel cohort

OBJECTIVES: To assess professional status (PS) differences in the risk of road crash involvement (RCI) (irrespective of crash severity), and to examine the underlying mechanism by evaluating the role of exposure to road risk (ERR). METHOD: A total of 15,271 subjects selected from the French GAZEL cohort were studied. A proportional hazard model for recurrent events was used to calculate the relative risks (RR) of RCI associated with PS. The associations between RCI and PS were investigated by adjusting for ERR (kilometers travelled and risk behaviors on the road). RESULTS: In all, 1890 RCI were reported. Managers have greater crude RCI risk than unskilled workers (male, RR=1.30; female, RR=1.44). This difference was no longer statistically significant when adjusting for factors describing the drivers' behaviors. Female managers' risks were also insignificant when adjusted for vehicle kilometers travelled (VKT). Managers seemed at lower risk of injury when involved in a crash. CONCLUSION: Socially advantaged subjects have the greatest RCI risk. Qualitative and quantitative ERR factors explain these disparities. These results highlight the importance to focus on ERR when studying the effect of an individual characteristic on RCI. They also highlight the importance to analyse separately the "RCI" and the "susceptibility to injury".     

Analgesics and road traffic crashes in senior drivers: An epidemiological review and explorative meta-analysis on opioids

Aim

To assess the epidemiological evidence associating the use of analgesics with the occurrence of road traffic crashes in senior drivers including a meta-analysis with specific focus on opioids.

Methods

Systematic literature review of articles published between 1991 and 2012 retrieved from major databases using relevant key words. Eligible articles were fully reviewed and the main characteristics and results summarized. The methodological quality was assessed using the Newcastle-Ottawa Scale. Heterogeneity tests and forest and funnel plots were used as part of the meta-analysis on opioids.

Results

From the potentially eligible articles, nine were selected (4 case–control, 1 case-crossover, and 4 cohort studies) of which four were of medium and five of high quality; seven investigated opioids and four non-steroidal anti-inflammatory drugs. Crash involvement (n = 7) rather than responsibility (n = 2) was investigated. Age and sex were the most common covariates adjusted for. Both opioids and non-steroidal anti-inflammatory drugs showed mixed results including differences across estimates between and within studies. A marginal positive effect was observed in the pooled analyses on opioids (n = 6, OR 1.20; 95% CI 1.08–1.32).

Conclusions

The evidence is unconvincing in terms of number of studies, control of major confounders, and consistency of the results. The effect seen for opioids can be attributed to the lack of adjustment of key confounders such as concomitant illness or the consumption of alcohol or other psychoactive medications. There is a need for more efficient designs like larger population-based retrospective cohorts and nested case–control or case-crossover studies based on registers of high quality allowing adjustment for these factors and for the selection of unequivocal outcomes (e.g. drivers’ responsibility) to produce more persuasive empirical evidence.     

Validation of selected temperament and personality questionnaires for diagnosing drivers’ aptitude for safe driving. A Polish study

This paper presents the results of a study aimed at validating psychological questionnaires evaluating temperamental and personality features. It discusses their usefulness in diagnosing drivers’ aptitude for safe driving and working as professional drivers. Three psychological questionnaires were validated: the Formal Characteristics of Behaviour – Temperament Inventory (FCB-TI), the Eysenck Personality Questionnaire – Revised and Short Scale (EPQ-R (S)) and the Impulsiveness Questionnaire (IVE). Three groups of drivers (n = 246) aged 19–75 participated in the study. Group I (professional drivers; n = 96) and Group II (nonprofessional drivers; n = 75) had never been involved in road crashes, whereas Group III (nonprofessional drivers; n = 75) were offenders involved in fatal injury road crashes. Criterion-related validity, Cronbach's alpha and Guttman split-half reliability coefficient were in assessing the psychometric properties of the questionnaires. There were some significant differences between Groups II and III for most traits. However, contrary to expectations, higher Emotional Reactivity, Perseveration and lower Endurance as well as higher Neuroticism, Impulsiveness and Venturesomeness were determined for Group II than for Group III. Additionally, the temperament and personality profile of Group II turned out to be less fitted to the profile of safe drivers than that of Group III, whose profile was actually similar to that of Group I. This seems to result from a high tendency for a positive self-presentation among Group I and Group III (a significantly higher result on the Lie scale in comparison with Group II). The results suggest that if psychological tests are to decide on whether a person may be a professional driver or may drive vehicles, the three questionnaires (FCB-TI, EPQ-R(S) and IVE) do not provide a valid diagnosis of professional drivers’ aptitude because of drivers’ high tendency for positive self-presentation. However, they can be used in job counselling and in screening high-risk drivers.     

The frequency and predictors of helmet use among Iranian motorcyclists: A quantitative and qualitative study

Objective

This study examines the rate of helmet use and identifies barriers and facilitators of wearing helmets among Iranian motorcyclists. A mixed-method approach was used, including a structured seasonal survey with specific observations of a random sample of 6010 riders and qualitative methods that included 29 in-depth interviews and seven focus groups (n = 31).

Results

Only 10% of motorcyclists wear a standard helmet while riding. However, another 23% of motorcyclists used non-standard or partial helmets that covered only part of the head and do not prevent head trauma injuries effectively. We observed only 2 of 264 child passengers and 22 of 1951 adult passengers wearing helmets. Almost no one used protective pants or clothing made to be more visible in traffic. Themes emerged from qualitative interviews and were grouped into three main categories: (1) helmet characteristics; (2) social and cultural factors; and (3) personal and psychological factors.

Conclusion

Overall, the motorcyclists in our study believed that wearing a safety helmet protects them against serious injuries or death during a crash; however, only a small percentage of the motorcyclists used safety helmets. National intervention programs addressing motorcycle safety should aim to overcome barriers to and promote facilitators of helmet use, including providing inexpensive standard helmets, banning manufacturing/using unsafe partial or dummy helmets, as well as enforcing helmet use on a consistent basis.     

Health status recovery at one year in children injured in a road accident: A cohort study

Despite the frequency of traumatic injuries due to road accidents and potential importance of identifying children at risk of impaired recovery one year after a road accident, there is a lack of data on long-term recovery of health status, except in children with severe traumatic brain injury. The aim of the present study was to evaluate predictive factors of recovery in children one year after road traffic injuries. The prospective cohort study was composed of children aged <16 years, admitted to public or private sector hospitals in the Rhône administrative area of France following a road accident. Recovery of health status one year after the accident and information concerning quality of life and the consequences of the accident for the child or family 1 year after the accident were collected by questionnaire, usually completed by the parents. Victims were in majority male (64.6%) and had mild or moderate injuries (81.9% with Maximum Abbreviated Injury Scale (M-AIS) <3). One year after the accident, 75.0% of the mild-to-moderate and 34.8% of the severe cases estimated health status as fully recovered. After adjustment, severity score (M-AIS ≥ 3) and lower limb injury (AIS > 1) were associated with incomplete recovery of health status: weighted odds ratio (OR_w), 4.3 [95% confidence interval (95% CI), 1.3–14.6] and OR_w, 6.5 [95% CI, 1.9–21.7], respectively. Recovery status correlated significantly with quality of life physical scores (r = 0.46), especially body pain (r = 0.48) and role/social–physical (r = 0.50) and, to a lesser extent, quality of life psychosocial scores (r = 0.21). In a cohort of children injured in a road accident, those with high injury severity score and those with lower limb injuries are less likely to recover full health status by 1 year. Impaired health status was associated with a lower physical quality of life score at 1 year.     

Driver characteristics associated with child safety seat usage in Malaysia: A cross-sectional study

Background

The rapidly motorizing environment in Malaysia has made child occupant safety a current public health concern. The usage of child safety seats (CSS) is a widely regarded intervention to enhance child occupant safety, yet no study has been conducted on CSS in Malaysia. This study aims to determine the CSS usage rates in Malaysia and to assess driver characteristics that are associated with CSS usage.

Methods

Nine variables - urban versus rural study location, age, gender, marital status, educational status, monthly family income, number of children present in the vehicle, distance traveled to the study location, and attitude - were examined through a cross-sectional study of interviewing drivers of 230 vehicles transporting at least one child <10 years of age at the time of the study. The vehicles were also observed for whether or not there was a CSS present. The interviews were conducted at six sampling locations - three urban and three rural - in the state of Melaka.

Results

27.4% of the drivers were found to be using at least one CSS at the time of the survey. Among the nine variables studied, three of the driver characteristics showed statistical significance (p < 0.05) with CSS usage: age (p = 0.047), educational status (p = 0.009), and attitude (p = 0.009).

Discussion

This study begins to create knowledge on child occupant safety in Malaysia. The results indicate that interventional efforts should focus on educational programs geared toward drivers that are less educated or extended family members who inconsistently transport young children. Furthermore, any educational efforts could be strongly enhanced by legislation mandating the use of CSS. Every effort should be made to thoroughly assess the effectiveness of any educational or legislative activities that are implemented.     

Road crash fatality rates in France: A comparison of road user types,taking account of travel practices

Background

Travel practices are changing: bicycle and motorized two-wheeler (MTW) use are rising in some of France’s large cities. These are cheaper modes of transport and therefore attractive at a time of economic crisis, but they also allow their users to avoid traffic congestion. At the same time, active transport modes such as walking and cycling are encouraged because they are beneficial to health and reduce pollution. It is therefore important to find out more about the road crash risks of the different modes of transport. To do this, we need to take account of the number of individuals who use each, and, even better, their travel levels.

Method

We estimated the exposure-based fatality rates for road traffic crashes in France, on the basis of the ratio between the number of fatalities and exposure to road accident risk. Fatality data were obtained from the French national police database of road traffic casualties in the period 2007–2008. Exposure data was estimated from the latest national household travel survey (ENTD) which was conducted from April 2007 to April 2008. Three quantities of travel were computed for each mode of transport: (1) the number of trips, (2) the distance traveled and (3) the time spent traveling. Annual fatality rates were assessed by road user type, age and sex.

Results

The overall annual fatality rates were 6.3 per 100 million trips, 5.8 per billion kilometers traveled and 0.20 per million hours spent traveling. The fatality rates differed according to road user type, age and sex. The risk of being killed was 20 to 32 times higher for motorized two-wheeler users than for car occupants. For cyclists, the risk of being killed, both on the basis of time spent traveling and the number of trips was about 1.5 times higher than for car occupants. Risk for pedestrians compared to car occupants was similar according to time spent traveling, lower according to the number of trips and higher according to the distance traveled. People from the 17–20 and 21–29 age groups and those aged 70 and over had the highest rates. Males had higher rates than females, by a factor of between 2 and 3.

Conclusion

When exposure is taken into account, the risks for motorized two-wheeler users are extremely high compared to other types of road user. This disparity can be explained by the combination of speed and a lack of protection (except for helmets). The differential is so great that prevention measures could probably not eliminate it. The question that arises is as follows: with regard to public health, should not the use of MTW, or at least of motorcycles, be deterred? The difference between the fatality risk of cyclists and of car occupants is much smaller (1.5 times higher); besides, there is much room for improvements in cyclist safety, for instance by increasing the use of helmets and conspicuity equipment. Traffic calming could also benefit cyclists, pedestrians and perhaps moped users.     

The impact of driver age on lost life years for other road users in France: A population based study of crash-involved road users

BACKGROUND: One of the concerns in road safety is the threat older drivers may pose to other road users. Using the rate of lost life years, the present study provides a public health approach to quantify this potential threat. METHODS: A total of 1570686 motorised vehicle drivers or motorcycle riders and 652246 non-drivers, i.e. vehicle passengers, pedestrians and cyclists involved in injury crashes in France between 1996 and 2004, were included in a population based cross-sectional study. Fatality rates and rate of lost life years for each crash-involved driver age class were calculated for the drivers themselves and for other road users. RESULTS: The study has shown a significant reduction in the rate of lost life years for crash-involved other road users (whether passengers, pedestrians, cyclists or opposing drivers) as driver age increases. Other road users lost half as many years of life when involved in crashes with drivers aged over 85 than with drivers under 65 (1.26 and 2.32 per 100 expected remaining life years, respectively). CONCLUSION: Our findings suggest that among road users involved in injury crashes, older drivers are less dangerous for the other road users. By attributing other road users' lost life years to each driver age, this study represents a new contribution to the debate about ageing and road safety.     

Comparing single vehicle and multivehicle fatal road crashes: A joint analysis of road conditions,time variables and driver characteristics

The difference between single vehicle crashes and multivehicle crashes was investigated in a collection of fatal crashes from six European countries. Variables with respect to road conditions, time variables, and participant characteristics were studied separately at first and then jointly in a logistic multiple regression model allowing to weigh different accounts of single vehicle as opposed to multivehicle crash occurrence.     

Antilock brakes and the risk of driver injury in a crash: a case-control study

While antilock brakes can improve steering and reduce stopping distance in some test situations, there is little evidence that they reduce the risk of crash-related injury. We sought to estimate the association between presence of antilock brakes and the risk of driver injury. We conducted a case-control study using claims data from the Insurance Corporation of British Columbia, Canada, for passenger vehicles insured during July 1, 2003, to June 30, 2004. Cases were 5000 vehicles with a driver crash injury during the study period. Controls were 49,994 vehicles insured at the mid-point of the study interval. The adjusted risk ratio for a crash with driver injury in a vehicle with antilock brakes was 1.06 (95% confidence interval, 0.95-1.17), compared with a vehicle without antilock brakes. If this estimated association is causal, antilock brakes do not prevent crash-related driver injuries.     

Hotspots and social background of urban traffic crashes: A case study in Cluj-Napoca (Romania)

Mobility practices have changed dramatically in Romanian towns over the last 25 years, following the collapse of socialist mobility restrictions. Urban areas like Cluj-Napoca are facing both increasing immigration and car mobility, and therefore increasing levels of road traffic crashes.The analysis of traffic crashes is one of the most important elements for improving the road safety policy. This paper is divided in two parts. In the first one, the authors focus on identifying the traffic crash hotspots along the street network, while in the second part they discuss the social background of road traffic crash occurrence.The first step in analyzing traffic crashes is to determine crash hotspots. A four-year record (2010–2013) provided by the Traffic Department of the General Inspectorate of Romanian Police (GIRPTD) was used. As a method of hotspot determination, the Kernel Density Estimation tool was employed, in the frame of the spatial analysis along network (SANET). The outcome was the hotspot map of traffic crashes in Cluj-Napoca. The results have revealed 4 categories of street segments: not-dangerous, low-dangerous, medium-dangerous and high-dangerous. Based on this classification, at least 4 dangerous areas were identified, located at the city entrances-exits (in the West, North-West and East) and the city center (the most dangerous zone).The second part of the paper focuses on social groups involved in car crashes. The following are considered: age, gender and blood alcohol concentration of the person (driver or pedestrian) found guilty for every individual crash.     

The effect of different delineator post configurations on driver speed in night-time traffic: A driving simulator study

The aim of the study was to investigate how different delineator post configurations affect driver speed in night-time traffic. In addition, the potential speed effect of introducing a secondary task was investigated. The study was carried out in a car simulator on a road stretch including straight road sections as well as curves with different radii. Fourteen drivers participated in the study and the results show that absence of delineator posts leads to reduced speed. However, provided that there are delineator posts continuously present along the road, the overall driver speed is basically the same, regardless of the spacing between the delineator posts. The results also imply that to reduce driver speed in curves with small radius, using more compact spacing of posts in these curves as compared to in curves with a larger radius, could be a potential strategy. Additionally, the speed reducing effect of a secondary task was only prevailing where the task was initiated.     

Association between increase in fixed penalties and road safety outcomes: A meta-analysis

Studies that have evaluated the association between increases in traffic fine amounts (fixed penalties) and changes in compliance with road traffic law or the number of accidents are synthesised by means of meta-analysis. The studies were few and different in many respects. Nine studies were included in the meta-analysis of changes in compliance. Four studies were included in the meta-analysis of changes in accidents. Increasing traffic fines was found to be associated with small changes in the rate of violations. The changes were non-linear. For increases up to about 100%, violations were reduced. For larger increases, no reduction in violations was found. A small reduction in fatal accidents was associated with increased fixed penalties, varying between studies from less than 1–12%. The main pattern of changes in violations was similar in the fixed-effects and random-effects models of meta-analysis, meta-regression and when simple (non-weighted) mean values were computed. The main findings are thus robust, although most of the primary studies did not control very well for potentially confounding factors. Summary estimates of changes in violations or accidents should be treated as provisional and do not necessarily reflect causal relationships.     

The effectiveness of audio-tactile lane-marking in reducing various types of crash: A review of evidence, template for evaluation, and preliminary findings from Australia

Audio-tactile lane-marking (ATLM) is designed to alert inattentive drivers when they deviate from their lane. Most commonly used previously to mark the edges of divided freeways, it is increasingly used to mark the edge and/or centre of two-lane undivided roads. We present a detailed review of ATLM evaluations to demonstrate that although both edge- and centreline ATLM appear to be effective, evaluations have been flawed insofar as they have (1) often not controlled adequately for variations due to extraneous factors known to affect crash incidence; (2) often focussed on total crashes, or on inattention-related crashes, and failed to address the possibility that ATLM increases some crash-types (particularly crashes involving two-wheeled vehicles, out-of-control crashes, or crashes on the opposite side of the lane to which the ATLM is installed); (3) almost always related to the milled-in “rumble strips” employed in the US rather than the raised profile lane-marking (PLM) that is employed in Australia. The present Empirical Bayes analysis aimed to evaluate PLM by comparing treated and untreated sections of the same roads both before and after the date of treatment in terms a range of crash types (some separately for roads with only edgeline-PLM, with only centreline-PLM, and with both edgeline- and centreline-PLM). Although some of the above issues could not be addressed due to insufficient data, the analysis provides a useful template for future researchers. The results provide evidence that both edgeline and centreline (alone or in combination) reduce targeted (same-side) crashes. Although there is no evidence that edgeline and centreline alone increase opposite side crashes, only edgeline and centreline together produced a net reduction in total crashes. Thus, the present results suggest that installing PLM on both edgeline and centreline is preferable to installing either alone.