Road rage among drug dependent patients

The consumption of alcohol, cocaine and cannabis is associated with aggressive behaviour, being a victim of injuries from various causes, and suffering traffic accidents. On the other hand, there is a significant association between road rage and traffic accidents, yet this has not been studied in persons suffering a substance dependence disorder. This study analyses the prevalence of road rage in substance dependent patients undergoing treatment. 100 patients randomly selected at an outpatient treatment centre were included in the study. 63% of the patients had experienced road rage in the year prior to the interview, and 18% were serious perpetrators. There was a higher frequency among drivers and those who were starting treatment for cocaine and cocaine + heroin. The study shows that road rage is very frequent among patients with disorders due to substance dependence who are undergoing treatment, in particular the most severe form (“serious perpetrators”). Special attention should be addressed to the issue of driving and road rage during the treatment of these patients.     

Alcohol, psychoactive drugs and fatal road traffic accidents in Norway: a case-control study

A case–control study was conducted on 204 drivers fatally injured in road traffic accidents in south-eastern Norway during the period 2003–2008. Cases from single vehicle accidents (N = 68) were assessed separately. As controls, 10 540 drivers selected in a roadside survey in the same geographical area during 2005–2006 were used. Blood samples were collected from the cases and oral fluid (saliva) samples from the controls. Samples were analysed for alcohol, amphetamines, cannabis, cocaine, opioid analgesics, hypnotics, sedatives and a muscle relaxant; altogether 22 psychoactive substances. Equivalent cutoff concentrations for blood and oral fluid were used. The risk for fatal injury in a road traffic accident was estimated using logistic regression adjusting for gender, age, season of the year, and time of the week. The odds for involvement in fatal road traffic accidents for different substances or combination of substances were in increasing order: single drug < multiple drugs < alcohol only < alcohol + drugs. For single substance use: medicinal drug or THC < amphetamine/methamphetamine < alcohol. For most substances, higher ORs were found when studying drivers involved in single vehicle accidents than for those involved in multiple vehicle accidents, but confidence intervals were wider.     

Alcoholism at the time of injury among trauma center patients: Vehicular crash victims compared with other patients

A structured in-depth interview employing standardized criteria was used to determine the prevalence of lifetime and current alcohol dependence (alcoholism) in unselected consecutive patients admitted to a regional Level I trauma center. Of 629 patients, 157 (25.0%) were current alcoholics at the time of injury. An additional 87 (13.8%) were diagnosed as lifetime non-current alcoholics. There was no significant difference in the rates of current alcohol dependence among patients injured in vehicular crashes (23.5%), other unintentional trauma victims (29.3%), and those injured as a result of violence (24.6%). Of BAC + (blood alcohol concentration positive) patients, 54.5% were current alcoholics. However, 14.4% of alcohol-negative patients were also diagnosed as alcohol dependent.     

Cycling to work in Brazil: Users profile, risk behaviors, and traffic accident occurrence

In 2006, we carried out a cross-sectional study in the urban area of Pelotas, Southern Brazil, with the aim of outlining the profile of bicycle commuters, analyzing their use of safety equipment and risk behaviors and the association between these variables and involvement in traffic accidents in the previous 12 months. This study was based on the baseline survey carried out prior to an educational intervention aimed at reducing accidents among cyclists. The sample included 1133 male subjects aged 20 years or more, and who used a bicycle for commuting. Crude and adjusted analyses were carried out using Poisson regression. We recorded a total of 152 reported traffic accidents in the 12 months preceding the interview, involving 10.8% of subjects. Most risk behaviors studied and the use of safety equipment showed no significant association with accidents. Only commuting by bicycle seven days per week, as opposed to five or six, and a combination of extremely imprudent behaviors such as zigzagging through traffic, riding after ingesting alcohol, and high-speed riding were found to be risk factors for accidents. Our findings suggest that in the context where the study was done (poor road signaling, limited policing, aggressive driving) changing cyclist behavior may not have substantial impact in terms of accident reduction before other road traffic interventions are implemented.     

A population-based study on the prevalence and correlates of drinking and driving in Hong Kong

To examine the prevalence and correlates of drinking and driving in Hong Kong, an anonymous, random telephone survey was conducted on 9860 Chinese adults (18-70 years of age) from April to June 2006. Trained interviewers administered a structured interview consisting of questions on socio-demographic information, drinking pattern, drink-driving, and motor vehicle accidents. The census age-standardized past-year prevalence of driving within 2 h of drinking was 5.2% among males and 0.8% among females. The prevalence across age showed an inverted U-shaped trend for males peaking at 8.2% between 41 and 45 years. For females the prevalence was fairly stable between the ages of 20 and 55. The past-year prevalence of alcohol-related motor vehicle accidents was 0.1%, with the majority being in the 26-30 age group. For males who drank, the prevalence of drinking and driving was 5.0% among those without problem drinking, 14.8% among binge drinkers, 37.1% among alcohol abusers and 22.4% among the alcohol dependent. For females who drank, the corresponding figures were all lower at 1.2%, 6.9%, 12.1% and 12.5%, respectively. Higher socio-economic status, weekly drinking, binge drinking and alcohol abuse were independently associated with higher likelihood of drinking and driving in both genders. Among drinking drivers, having a job that required drinking was the only predictor of having had a motor vehicle accident. The elevated prevalence of drinking and driving among alcohol abusers, binge drinkers and the alcohol dependent may portend higher population-level rates of alcohol-related motor accidents in the future since the prevalence of problem drinking has previously been noted to be increasing rapidly in Hong Kong.     

Alcohol consumption as an incremental factor in health care costs for traffic accident victims: Evidence in a medium sized Colombian city

Objectives

Identify the possibility that alcohol consumption represents an incremental factor in healthcare costs of patients involved in traffic accidents.

Methods

Data of people admitted into three major health institutions from an intermediate city in Colombia was collected. Socio-demographic characteristics, health care costs and alcohol consumption levels by breath alcohol concentration (BrAC) methodology were identified. Generalized linear models were applied to investigate whether alcohol consumption acts as an incremental factor for healthcare costs.

Results

The average cost of healthcare was 878 USD. In general, there are differences between health care costs for patients with positive blood alcohol level compared with those who had negative levels. Univariate analysis shows that the average cost of care can be 2.26 times higher (95% CI: 1.20–4.23), and after controlling for patient characteristics, alcohol consumption represents an incremental factor of almost 1.66 times (95% CI: 1.05–2.62).

Conclusions

Alcohol is identified as a possible factor associated with the increased use of direct health care resources. The estimates show the need to implement and enhance prevention programs against alcohol consumption among citizens, in order to mitigate the impact that traffic accidents have on their health status. The law enforcement to help reduce driving under the influence of alcoholic beverages could help to diminish the economic and social impacts of this problem.     

Cannabis use and traffic accidents in a birth cohort of young adults

Objective: to examine linkages between cannabis use and traffic accident risks in a birth cohort of 907 young New Zealanders studied from 18 to 21 years. Methods: during the course of a 21-year longitudinal study of a birth cohort of 907 New Zealand born children information was gathered on (a) annual frequency of cannabis use over the period from 18 to 21 years; (b) annual rates of traffic accidents during the period 18–21 years; (c) measures of driver behaviours and characteristics. The association between cannabis use and traffic accident risk was examined among the 907 sample members who reported driving a motor vehicle between the ages of 18 and 21 years. Results: there were statistically significant relationships between reported annual cannabis use and annual accident rates. This association was present only for ‘active’ accidents in which driver behaviours contributed to the accident; those using cannabis more than 50 times per year had estimated rates of active accidents that were 1.6 (95% CI 1.2–2.0) times higher than the rate for non-users. However, statistical control for driver behaviours and characteristics related to cannabis use (drink driving behaviour; risky/illegal driving behaviours; driver attitudes; gender) eliminated the association between cannabis use and traffic accident risks. Conclusions: although cannabis use was associated with increased risks of traffic accidents among members of this birth cohort, these increased risks appear to reflect the characteristics of the young people who used cannabis rather than the effects of cannabis use on driver performance.     

Collisions and traffic violations of alcohol, cannabis and cocaine abuse clients before and after treatment

Prior research has shown that those with alcohol problems have significantly elevated rates of traffic events (i.e. traffic violations and collisions) than licensed drivers from the general population and that treatment is associated with reductions in alcohol-related collisions. However, very little research exists on traffic events and the impact of treatment for cannabis or cocaine clients. The objectives of this research are: (1) to determine whether clients in treatment for a primary problem of alcohol, cannabis or cocaine have significantly elevated rates of traffic events than a matched control group of licensed drivers; and (2) to assess whether a significant reduction in traffic events occurs after treatment for each client group compared to a control group. Driver records of patients admitted to substance abuse treatment in 1994 for a primary problem of alcohol (n = 117), cannabis (n = 80) or cocaine (n = 169) were accessed from the Ministry of Transportation for Ontario, Canada. A comparison group of 504 licensed drivers frequency matched by age, sex and place of residence, was also randomly selected. Data was collapsed into two 6-year time periods: 1988-1993 (i.e. before treatment) and 1995-2000 (i.e. after treatment). Six repeated measures analysis of variance tests were conducted where traffic violations and collisions of three treatment groups (i.e. alcohol, cannabis or cocaine) and a control group were compared before and after treatment. All three treatment groups had significantly more traffic violations than the control group and no significant interactions between time period and group membership were found. For collisions, there was a significant interaction between the alcohol and control groups and between the cocaine and control groups. The average number of collisions for the alcohol and cocaine groups decreased after completing treatment, whereas the number for the control group was stable over the same time periods. Neither the interaction term nor the between group effect was significant in the comparison of the cannabis and control groups. When rates of collisions were calculated based on the period that each driver had a valid license, the interaction term was still significant for the comparison of the alcohol and control groups but not for the cocaine and control groups. The results contribute to existing literature by demonstrating that cocaine and cannabis clients have a higher risk of traffic violations than matched controls and that reductions in collision risk was found after treatment for the alcohol and cocaine groups. More research is needed to better understand the reasons for the higher risk of traffic events and to determine reasons for declines.     

Sleep debt,sleepiness and accidents among males in the general population and male professional drivers

Men from the general population and male professional lorry and bus drivers were surveyed with regard to sleep habits and motor vehicle and other types of accidents. A random sample of 4000 men in the general population of Dalarna County in mid-Sweden were mailed a questionnaire and served as referents. A total of 1389 male professional lorry and bus drivers from this county responded to the same questionnaire. A total of 161 of the drivers also underwent a sleep study in their homes.The proportion of total accidents was higher among the professional drivers as compared with the males in the population, P=0.03. Reports on traffic accidents were the same in both groups, but the professional drivers reported more accidents at leisure compared with referents, P<0.0001. Accidents of any kind, traffic accidents included, among those affected by both snoring and apneas, were not reported more in either of the groups. At the sleep study, 17% of those examined received the diagnosis of obstructive sleep-apnea syndrome (OSAS).The professional drivers reported proportionally more sleep debt than the referents, P<0.001. Among referents, traffic accidents at leisure, traffic accidents while commuting and accidents at work increased in proportion to sleep debt (P<0.001, 0.006 and 0.002, respectively). The finding that self-perceived sleep debt may have an adverse effect on males in the general population and male professional drivers concerning accident likelihood should have an impact on prevention. These results stress the need to educate the general population on the importance of complying with our biological need of sleep.     

Profiling drunk driving recidivists in Denmark

Drunk drivers are a menace to themselves and to other road users, as drunk driving significantly increases the risk of involvement in road accidents and the probability of severe or fatal injuries. Although injuries and fatalities related to road accidents have decreased in recent decades, the prevalence of drunk driving among drivers killed in road accidents has remained stable, at around 25% or more during the past 10 years. Understanding drunk driving, and in particular, recidivism, is essential for designing effective countermeasures, and accordingly, the present study aims at identifying the differences between non-drunk drivers, drunk driving non-recidivists and drunk driving recidivists with respect to their demographic and socio-economic characteristics, road accident involvement and other traffic and non-traffic-related law violations. This study is based on register-data from Statistics Denmark and includes information from 2008 to 2012 for the entire population, aged 18 or older, of Denmark. The results from univariate and multivariate statistical analyses reveal a five year prevalence of 17% for drunk driving recidivism, and a significant relation between recidivism and the drunk drivers’ gender, age, income, education, receipt of an early retirement pension, household type, and residential area. Moreover, recidivists are found to have a higher involvement in alcohol-related road accidents, as well as other traffic and, in particular, non-traffic-related offences. These findings indicate that drunk driving recidivism is more likely to occur among persons who are in situations of socio-economic disadvantage and marginalisation. Thus, to increase their effectiveness, preventive measures aiming to reduce drunk driving should also address issues related to the general life situations of the drunk driving recidivists that contribute to an increased risk of drunk driving recidivism.     

The prevalence of drugs in motor vehicle accidents and traffic violations in Shanghai and neighboring cities

The objective of this study was to determine the prevalence of psychoactive drug use among motor vehicle drivers in Shanghai and its neighboring cities. We selected 10,002 drivers involved in a traffic accident or violation between 2007 and 2008 in Shanghai, Suzhou and Wuxi. We checked for the presence of psychoactive drugs from blood samples using liquid chromatography tandem mass spectrometry (LC–MS–MS). Of the 10,002 drivers, 10.5% tested positive for drugs (excluding alcohol). Cold medicines were the most frequently detected drugs including chlorpheniramine (4.78%), pseudoephedrine (2.15%) and paracetamol (1.32%). The use of multiple cold medicines was common. Illegal drugs such as methamphetamine (0.15%), ketamine (0.03%) and MDMA (0.01%) were also detected. The prevalence of psychoactive drugs among drivers involved in traffic accidents or violations in Shanghai and its neighboring cities was lower compared to previous reports in Europe. Furthermore, cannabis—which has been reported to be the most widely used psychoactive drug after alcohol—was not commonly encountered among Shanghai drivers.     

Primary prevention of drink driving by the large-scale use of alcolocks in commercial vehicles

Alcolocks are commercial breath test devices that prevent a motor vehicle from starting when a driver's blood alcohol concentration (BAC) is elevated. This report is an evaluation of the experiences and BAC data from the first use of alcolocks in commercial vehicles as a primary prevention strategy. In most applications, the alcolock is imposed only after an impaired driving conviction. This study, implemented in Sweden, estimates drink driving on a large scale in a variety of commercial vehicles. Officials from 118 companies were interviewed representing 3689 alcolock-equipped vehicles used by 9614 professional drivers, an 80% compliance rate. In a contrast group of 230 transport businesses without alcolocks the interview compliance rate was 57%. Survey results probed motivation for and experience with alcolocks. Analysis of BAC test patterns showed alcohol consumption among employees through prevalence estimates of drink-driving attempts at the rate of BAC> or =the legal limit 0.020%. Before alcolock installation, 64% of the employers suspected alcohol problems among their employees and their motive for installing alcolocks (cost averaged 1700 euro/vehicle) was to improve the transport quality. Several companies had technical problems with the alcolocks; but 98% recommended that other companies install alcolocks. Among 600, heavy vehicles, 0.19% of all starts were prevented by elevated BAC; most during weekends and mornings. Daytime Saturday and Sunday mornings 0.72% of the drivers had elevated BAC. CONCLUSIONS: The prevalence of drink driving among professional drivers is probably similar to that among drivers in general. Alcolocks would improve the safety margin and reduce public risk. Provided that the entire fleet of trucks, buses, and taxis in Sweden had installed alcolocks that would correspond to about half a million drink driving trips being prevented every year.     

Convicted of fatigued driving: Who, why and how?

Fatigue is a major cause of road traffic accidents. However, due to the blurred concept of fatigue and the lack of reliable testing devices (cf. the breath analyzer for alcohol levels), it is extremely difficult to incorporate fatigue in operationalized terms into either traffic or criminal law. Even though the Finnish Road Traffic Act explicitly forbids driving while tired, it is done only on a general level among other factors (sickness, etc.) that impair a driver's fitness to drive (Article 63). The present study was done to investigate the circumstances of fatigue driving offenses. From the Finnish Vehicle Administration driver record database we extracted all drivers (N = 768) punished under Article 63 from 2004-2005. Of these drivers, 90.4% committed a fatigue-related traffic offense. Accidents, predominantly single vehicle, were the most common (92.5%) consequence of fatigued driving. Although fatigue-related accidents are thought to be serious, our data shows that most of the accidents (81.6%) did not involve personal injuries. Almost every twentieth driver was punished because his vehicle was drifting on the road. The presence of alcohol or drugs was noted in 13% of the cases. Only 3.1% of the punished drivers officially denied being tired or falling asleep. Young men (≤35 yrs) represented 50% of all punished drivers. Time of day and seasonal effects were clear in this data. This study shows that even without a reliable fatigue detector and unambiguous criteria for recognizing the contribution of fatigue to accident causation, Finnish police and the courts punish a significant number of drivers every year on the basis of fatigue.     

Substance use and social,health and safety-related factors among fatally injured drivers

Objective

The aim of this study was to examine different socio-demographic, health and safety-related factors, and psychoactive substance use among fatally injured drivers in road traffic accidents in Finland during 2006–2008.

Methods

An accident information register maintained by the Traffic Safety Committee of Insurance Companies (VALT) of the Finnish Motor Insurers’ Centre was used as basic data, and the basic data were complemented with further toxicological analytical information retrieved from autopsy reports from the Department of Forensic Medicine, Helsinki University. The data included all the drivers (n = 556) who were driving a motor vehicle and who died in a road traffic accident in Finland during 2006–2008.

Results

Of all the 556 fatally injured drivers 43% (n = 238) had psychoactive substance findings. 51% (n = 121) of substance positive drivers had a finding for alcohol only, the rest had a finding for one or more illicit/medicinal drugs impairing driving ability, and possibly also alcohol. Fatally injured drivers with alcohol findings were significantly younger (mean age 34 years) than sober drivers (mean age 44 years) or drivers with findings for drugs (mean age 45 years). Socio-demographic background did not differ substantially among drunken/drugged and sober drivers, although drivers with alcohol findings had a slightly lower education and socioeconomic position. Previous substance abuse problems were highly prevalent among drivers with substance findings and mental or both mental and physical health problems were more common among drivers with drug findings. The non-use of safety equipment and driving at a high speed were more common among fatally injured drivers with substance findings.

Conclusions

Substance abuse and mental health problems, as well as reckless driving behavior were more pronounced among fatally injured drivers with substance findings when compared to sober drivers. Thus, prevention and early intervention concerning substance abuse, mental health problems and DUI are essential. Improved traffic safety cannot be achieved by means of traffic policy only, but integration with other policies, such as health and social policy should be strengthened.     

Alcohol and fatal accidents in the United States--a time series analysis for 1950-2002

AIMS: To estimate the association between per capita alcohol consumption and fatal accidents in the United States and to compare the outcome with findings from Europe and Canada. DATA AND METHOD: Yearly data on fatal accidents by gender and age were analysed in relation to per capita alcohol consumption for 1950-2002 using the Box-Jenkins technique for time series analysis. FINDINGS: A 1-L increase in per capita consumption was on average followed by 4.4 male deaths per 100,000 inhabitants, but had no significant effect on female accident mortality. Regarding specific categories of accidents, the effect on fatal motor vehicle accidents accounted for a large part of the overall effect for men and was also significant for women. With respect to fatal falling accidents and other accidents, the only significant effects were found among young males. As concerns women, the association with per capita consumption in the US was weak in comparison with Canada and Europe. The US effect estimate for overall male accidents was however equally strong as in Northern Europe (5.2) or Canada (5.9), and stronger than that found in Central and Southern Europe (2.1 and 1.6, respectively). With respect to alcohol and fatal motor vehicle accidents, the association for men of 3.2 was stronger than in Europe and more similar to the Canadian finding (3.6). CONCLUSIONS: Per capita alcohol consumption has at least partly been an explanation for the development of male fatal accidents and particularly motor vehicle accident rates in the post-war United States. High traffic density and relatively high legal limits for drunken driving blood alcohol concentration (BAC) are suggested to explain the strong association found between alcohol and fatal motor vehicle accidents. The results also suggest that a reduction in per capita consumption would have its most preventive impact on fatal accidents among younger males.     

Factors associated with alcohol and drug use among traffic crash victims in southern Brazil

Objective

To investigate the prevalence of and factors associated with alcohol- or drug-related traffic crashes (TC) in a sample of TC victims who were admitted to the two emergency rooms of Porto Alegre in southern Brazil.

Methods

A cross-sectional study with consecutive samples was used. Victims of non-fatal TCs (as drivers, passengers or pedestrians) who had presented at emergency rooms during the 45 days of data collection were selected. Subjects participated in a structured interview, were breathalyzed and underwent salivary drug testing. A multinomial logistic regression model was used to verify factors associated with alcohol or drug use.

Results

Of the 609 victims who participated in the interview, 72% were male, and the median age was 29 years (interquartile range 23.0–40.0 years). The drivers were mostly men (p < 0.001), with a higher binge drinking rate (p = 0.003) and marijuana use (p = 0.005) than seen in pedestrian and passengers. The prevalence of a positive blood alcohol concentration (BAC) ranged from 7.8% among the drivers to 9.2% among the pedestrians (p = 0.861), and the cannabis prevalence was 13.3% among the drivers. The variables associated with an alcohol-related accident were binge drinking in the prior 12 months (OR 2.4; CI 95% 1.1–5.1) and coming from a party/bar (OR 8.7; CI 95% 2.8–26.7). Alcohol abuse or dependence increased by 5.2-fold the chance of another substance-related TC.

Conclusion

The large number of individuals found in TC-related emergency room visits in a short time frame is evidence of the Brazilian epidemic of TC. The data showed that alcohol abuse or dependence also increases the risk of intoxication by other drugs, and they point to alcohol and drug use as a major problem requiring specific TC-related public policies and law enforcement.     

Killer crashes: Fatal road traffic accidents in the UK

Road traffic accidents are responsible for over 3000 deaths per year in the UK, according to Department for Transport (2004a) figures. Although progress is being made in a number of areas, vehicle occupant fatalities have not been falling in line with casualty reduction targets for the year 2010. A sample of 1185 fatal vehicle occupant cases was considered, from ten UK police forces, from the years 1994-2005 inclusive. The main findings were: (1) over 65% of the accidents examined involved driving at excessive speed, a driver in excess of the legal alcohol limit, or the failure to wear a seat belt by a fatality, or some combination of these. (2) Young drivers have the great majority of their accidents by losing control on bends or curves, typically at night in rural areas and/or while driving for ‘leisure’ purposes. These accidents show high levels of speeding, alcohol involvement and recklessness. (3) Older drivers had fewer accidents, but those fatalities they were involved in tended to involve misjudgement and perceptual errors in ‘right of way’ collisions, typically in the daytime on rural rather than urban roads. Blameworthy right of way errors were notably high for drivers aged over 65 years, as a proportion of total fatal accidents in that age group.     

The relationship between alcoholrelated traffic fatalities and per capita consumption of alcohol, Ontario, 1957–1983

In this research, the impact of per capita consumption of alcohol on alcohol-related traffic fatalities in Ontario between 1957 and 1983 was examined. Three measures of alcohol involvement were selected. The first, drinking drivers (police reported) involved in fatal accidents, was a direct measure. The second and third, single-vehicle fatal accidents and nighttime fatal accidents, were surrogate measures. Also, three corresponding measures of fatal accidents not involving alcohol (normal drivers [police reported] involved in fatal accidents, multiple vehicle fatal accidents, and daytime fatal accidents) were chosen to control for general road safety trends. The results of regression analyses indicated that both per capita consumption and general road safety trends were significant contributors to all three measures of alcohol-involved fatalities. These and other recent data suggest that any effort to prevent alcohol-related problems such as liver cirrhosis through control of per capita consumption will also have a beneficial impact on alcohol-related accidents.     

Traffic safety assessment and development of predictive models for accidents on rural roads in Egypt

This paper starts by presenting a conceptualization of indicators, criteria and accidents' causes that can be used to describe traffic safety. The paper provides an assessment of traffic safety conditions for rural roads in Egypt. This is done through a three-step procedure. First, deaths per million vehicle kilometers are obtained and compared for Egypt, three other Arab countries and six of the G-7 countries. Egypt stands as having a significantly high rate of deaths per 100 million vehicle kilometers. This is followed by compiling available traffic and accident data for five main rural roads in Egypt over a 10-year period (1990-1999). These are used to compute and compare 13 traffic safety indicators for these roads. The third step for assessing traffic safety for rural roads in Egypt is concerned with presenting a detailed analysis of accident causes. The paper moves on to develop a number of statistical models that can be used in the prediction of the expected number of accidents, injuries, fatalities and casualties on the rural roads in Egypt. Time series data of traffic and accidents, over a 10 years period for the considered roads, is utilized in the calibration of these predictive models. Several functional forms are explored and tested in the calibration process. Before proceeding to the development of these models three ANOVA statistical tests are conducted to establish whether there are any significant differences in the data used for models' calibration as a result of differences among the considered five roads.