Vehicle mismatch: injury patterns and severity

Light truck vehicles (LTV) are becoming more popular on US highways. This creates greater opportunity for collisions with passenger vehicles (PV). The mismatch in weight, stiffness, and height between LTV and PV has been surmised to result in increased fatalities among PV occupants when their vehicles collide with LTV. We reviewed cases of vehicle mismatch collisions in the Seattle Crash Injury Research and Engineering Network (CIREN) database to establish patterns and source of injury. Of the first 200 Seattle CIREN cases reviewed, 32 collisions with 41 occupant cases were found to involve LTV versus PV. The cases were reviewed by type of collision and vehicle of injured occupant: side impact of PV with LTV, front impact of PV with LTV, and front impact of LTV with PV. For each type of crash, injury patterns and mechanisms were identified. For side impact to PV, head and upper thorax injuries were frequently encountered due to LTV bumper frame contact above the PV side door reinforcement. For frontal impact to PV, severe multiple extremity fractures along with some head and chest injuries were caused by intrusion of the instrument panel and steering column due to bumper frame override of the LTV. Underriding of the PV when colliding with the LTV resulted in severe lower extremity fractures of the LTV occupant due to intrusion of the toe pan into the vehicle compartment of the LTV. The injuries and the sources identified in this case series support the need for re-designing both LTV and PV to improve vehicle compatibility. Revising Federal Motor Vehicle Safety Standard 214 to reinforce the entire door, consider adding side airbags, and re-engineering LTV bumpers and/or frame heights and PV front ends are possible ways to reduce these injuries and deaths by making the vehicles more compatible.     

Light truck vehicles (LTVs) contribution to rear-end collisions

Light truck vehicles (LTVs), comprising light-duty trucks, vans, and sport-utility vehicles (SUVs) drive higher and wider than passenger cars which could affect the visibility for the following passenger car driver. This paper investigates the contribution of LTVs to rear-end collisions resulting from horizontal visibility blockage using the University of Central Florida sophisticated reconfigurable driving simulator. Indeed, a sudden stop of a leading LTV, in the shadow of the blindness of the succeeding passenger car driver, may deprive the latter of a sufficient response time, which may lead to high probability of a rear-end collision. To investigate this issue, two scenarios were developed in the UCF driving simulator. The first scenario serves as a base scenario where the simulator car follows a passenger car, and the second scenario serves as a test scenario, where the simulator car follows an LTV. The results obtained by comparing the scenarios showed that LTVs produce more rear-end collisions at unsignalized intersections due to horizontal visibility blockage and due to the resulting drivers' behavior when driving behind an LTV.     

Modeling rear-end collisions including the role of driver's visibility and light truck vehicles using a nested logit structure

This paper presents an analysis of the effect of the geometric incompatibility of light truck vehicles (LTV)--light-duty trucks, vans, and sport utility vehicles--on drivers' visibility of other passenger cars involved in rear-end collisions. The geometric incompatibility arises from the fact that most LTVs ride higher and are wider than regular passenger cars. The objective of this paper is to explore the effect of the lead vehicle's size on the rear-end crash configuration. Four rear-end crash configurations are defined based on the type of the two involved vehicles (lead and following vehicles). Nested logit models were calibrated to estimate the probabilities of the four rear-end crash configurations as a function of driver's age, gender, vehicle type, vehicle maneuver, light conditions, driver's visibility and speed. Results showed that driver's visibility and inattention in the following (striker) vehicle have the largest effect on being involved in a rear-end collision of configuration CarTrk (a regular passenger car striking an LTV). Possibly, indicating a sight distance problem. A driver of a smaller car following an LTV, have a problem seeing the roadway beyond the LTV, and therefore would not be able to adjust his/her speed accordingly, increasing the probability of a rear-end collision. Also, the probability of a CarTrk rear-end crash increases in the case that the lead vehicle stops suddenly.     

Traffic safety and the switch to a primary seat belt law: the California experience

This study explores whether the change of an existing seat belt law from secondary to primary enforcement enhances traffic safety. In particular, we examine traffic fatalities and injuries in California from 1988 to 1997. During the first half of this period, California law provided for secondary enforcement of its mandatory seat belt law, but in 1993 it upgraded the law to primary enforcement. Controlling for the number of motor vehicle collisions, a Box–Tiao intervention analysis of the time series is used to compare the monthly fatalities and injuries before and after the change in the enforcement provision. The results show that California experienced an improvement in traffic safety in terms of a significant reduction in injuries, but the change in enforcement provision had no statistically significant impact on fatalities.     

The fatality and injury risk of light truck impacts with pedestrians in the United States

In the United States, passenger vehicles are shifting from a fleet populated primarily by cars to a fleet dominated by light trucks and vans (LTVs). Because light trucks are heavier, stiffer, and geometrically more blunt than passenger cars, they pose a dramatically different type of threat to pedestrians. This paper investigates the effect of striking vehicle type on pedestrian fatalities and injuries. The analysis incorporates three major sources of data, the Fatality Analysis Reporting System (FARS), the General Estimates System (GES), and the Pedestrian Crash Data Study (PCDS). The paper presents and compares pedestrian impact risk factors for sport utility vehicles, pickup trucks, vans, and cars as developed from analyses of US accident statistics. Pedestrians are found to have a two to three times greater likelihood of dying when struck by an LTV than when struck by a car. Examination of pedestrian injury distributions reveals that, given an impact speed, the probability of serious head and thoracic injury is substantially greater when the striking vehicle is an LTV rather than a car.     

The turning point in the number of traffic fatalities: Two hypotheses about changes in underlying trends

The number of traffic fatalities reached a peak in many highly motorised countries around 1970. Some previous studies have suggested that the turning point in the number of traffic fatalities was inevitable and did not reflect a change in the underlying trends influencing the number of traffic fatalities. Other studies suggest that trends in traffic growth and fatality rate changed from before to after the turning point. This paper proposes two hypotheses about the turning point in the number of traffic fatalities. One hypothesis is that the long-term trends in traffic growth and fatality rate were the same before and after the turning point. The other hypothesis is that the long-term trends in traffic growth and fatality rate were different before and after the turning point was reached, in particular that the annual percentage decline in fatality rate became greater after the turning point than before. Such a change would suggest that road safety policy became more effective. Analysis of data for six countries (Denmark, Great Britain, Netherlands, Norway, Sweden, United States) lends stronger support to the latter hypothesis than to the former. The lesson for policy makers, in particular in countries where the number of traffic fatalities is still growing, is that they should not expect a turning point to be reached without policy interventions.     

Traffic fatalities and economic growth

This paper examines the relationship between traffic fatality risk and per capita income and uses it to forecast traffic fatalities by geographic region. Equations for the road death rate (fatalities/population) and its components--the rate of motorization (vehicles/population) and fatalities per vehicle (F/V)--are estimated using panel data from 1963 to 1999 for 88 countries. The natural logarithm of F/P, V/P, and F/V are expressed as spline (piecewise linear) functions of the logarithm of real per capita GDP (measured in 1985 international prices). Region-specific time trends during the period 1963-1999 are modeled in linear and log-linear form. These models are used to project traffic fatalities and the stock of motor vehicles to 2020. The per capita income at which traffic fatality risk (fatalities/population) begins to decline is 8600 US dollars (1985 international dollars) when separate time trends are used for each geographic region. This turning point is driven by the rate of decline in fatalities/vehicles as income rises since vehicles/population, while increasing with income at a decreasing rate, never declines with economic growth. Projections of future traffic fatalities suggest that the global road death toll will grow by approximately 66% over the next twenty years. This number, however, reflects divergent rates of change in different parts of the world: a decline in fatalities in high-income countries of approximately 28% versus an increase in fatalities of almost 92% in China and 147% in India. The road death rate is projected to rise to approximately 2 per 10,000 persons in developing countries by 2020, while it will fall to less than 1 per 10,000 in high-income countries.     

The role of alcohol use on recent trends in distracted driving

Distracted driving is now an increasingly deadly threat to road safety. We provide evidence that intoxicated driving is increasingly responsible for recent increases in fatalities from distracted driving crashes. This study describes trends in deaths on U.S. public roads caused by alcohol-involved and distracted drivers using the Fatality Analysis Reporting System (FARS)—a census of fatal crashes on U.S. public roads. Fatality rates per vehicle-miles traveled are calculated using data from the Federal Highway Administration. Alcohol-involved drivers who are simultaneously distracted were responsible for 1750 deaths in 2009, an increase of more than 63% from 2005 when there were 1072 deaths. Alcohol use while driving is increasingly responsible for a growing number of fatalities from distracted driving, accounting for 32% of deaths from distracted driving in 2009 versus 24% in 2005. The fatality rate from these crashes increased from 35.9 to 59.2 deaths per 100 billion vehicle-miles traveled after 2005. Alcohol use is quickly increasing as an important factor behind distracted driving fatalities. This has implications for policies combating distracted driving that do not address the role of alcohol use in distracted driving.     

Predicting seat belt use in fatal motor vehicle crashes from observation surveys of belt use

There is a large difference between the rates of observed seat belt use by the general public and belt use by motor vehicle occupants who are fatally injured in crashes. Seat belt use rates of fatally injured occupants, as reported in the Fatality Analysis Reporting System (FARS), are much lower than the use rates found in observation surveys conducted by the states. A series of mathematical models describing the empirical relationship between FARS and observed rates were explored. The initial model was a 'straw man' and used two simplifying assumptions: (a) belt users and nonusers are equally likely to be involved in 'potentially fatal collisions', and (b) belts are 45% effective in preventing deaths. The model was examined by comparing each state's FARS use rate with the predicted rate. The model did not fit the state data points even when possible biases in the data were controlled. We next examined the assumptions in the model. Changing the seat belt effectiveness parameter provided a reasonable fit, but required an assumption that seat belts are 67% effective in preventing fatalities. The inclusion of a risk coefficient for non-belted occupants also provided a reasonable fit between the model and data. A variable risk model produced the best fit with the data. The major finding was that a model consistent with the data can be obtained by incorporating the assumption that nonusers of seat belts have a higher risk of involvement in potentially fatal collisions than do seat belt users. It was concluded that unbelted occupants are over-represented in fatal collisions for two reasons: (a) because of a greater chance of involvement in potentially fatal collisions in the first place, and (b) because they are not afforded the protection of seat belts when a collision does occur.     

Evaluation of photo radar program in British Columbia

This article presents the results of an evaluation of the speed and traffic safety effects of the photo radar program in British Columbia (BC) after 1 year of full operation. Traffic speed data were collected from the photo radar units and from induction loops installed across the province. Traffic collision and injury data were obtained from police investigation reports and from BC ambulance services records. The study employed a number of analytical frameworks, including simple before and after comparison, time-series cross-sectional analysis, and interrupted time series analysis. The study revealed a dramatic reduction of speed at photo radar deployment sites. A reduction of 2.4 km/h in mean speed was also observed at selected monitoring sites where enforcement was not likely to be present. The reduction of speed was accompanied by a decrease in collisions, injuries and fatalities. The analysis found a 25% reduction in daytime unsafe speed related collisions, an 11% reduction in daytime traffic collision victims carried by ambulances and a 17%, reduction in daytime traffic collision fatalities.     

Restrained front seat car occupant fatalities--the nature and circumstances of their injuries.

The circumstances of a rural and urban sample of fatalities in vehicles less than six years old is described. The data originate from an in-depth, multidisciplinary study of accidents conducted in England since 1983. The sample is biased towards collisions that result in occupant injury, and this paper will concentrate on those accidents in which an occupant has been fatally injured. The initial police reporting of the fatalities included 11% of the deaths occurring from natural causes. Of the crash-related deaths with complete data, some 43% were frontal and lateral impacts, and they are analysed in greater detail. Thirty-six percent of restrained occupants died in lateral collisions. In both frontal and lateral crashes, large amounts of intrusion result in direct loading of the head and chest, particularly. Under-run crashes with large trucks constitute 30% of frontal death cases, and only 12% of fatalities received fatal injuries from belt loads. Of those cases, additional loading by unrestrained rear passengers could have been an important feature. Multiplicity of severe injuries is the rule for restrained fatalities, with head injuries as the most common cause of death. Eighty-two percent died within an hour of their crashes. Some consequences for vehicle compatibility in crashes are discussed.     

Passenger car collision fatalities--with special emphasis on collisions with heavy vehicles

Between 1995 and 2004, 293 passenger car occupants died in collisions with other vehicles in northern Sweden (annual incidence: 3.3 per 100,000 inhabitants, 6.9 per 100,000 cars, or 4.8 per 10(9)km driven); half of these deaths involved heavy vehicles. The annual number of passenger car occupant deaths per 100,000 cars in car-truck/bus collisions has remained unchanged since the 1980s, but in car-car collisions it has decreased to one third of its former level. As crash objects, trucks and buses killed five times as many car occupants per truck/bus kilometer driven as did cars. The collisions were characterized by crashes in the oncoming vehicle's lane, under icy, snowy, or wet conditions; crashes into heavy vehicles generally occurred in daylight, on workdays, in winter, and on 90 and 70 km/h two-lane roads. Head and chest injuries accounted for most of the fatal injuries. Multiple fatal injuries and critical and deadly head injuries characterized the deaths in collisions with heavy vehicles. An indication of suicide was present in 4% of the deaths; for those who crashed into trucks, this percentage was doubled. Among the driver victims, 4% had blood alcohol levels above the legal limit of 0.2g/L. Frontal collision risks might be reduced by a mid-barrier, by building less injurious fronts on trucks and buses, by efficient skid prevention, and by use of flexible speed limits varying with road and light conditions.     

Characteristics of fatal motorcycle crashes into roadside safety barriers in Australia and New Zealand

This paper reports on the findings of a retrospective case series study of fatal motorcyclist–roadside barrier collisions. Cases were retrieved from the National Coroners Information System (NCIS), the coronial case files of Australian jurisdictions, and the Crash Analysis System (CAS) of the New Zealand Transport Agency. Seventy seven (77) motorcycle fatalities involving a roadside barrier in Australia and New Zealand were examined. The fatalities usually involved a single vehicle crash and young men. The roadside barriers predominantly involved were steel W-beams, typically on a bend in the horizontal alignment of the road. A majority of fatalities occurred on a weekend, during daylight hours, on clear days with dry road surface conditions indicating predominantly recreational riding. Speeding and driving with a blood alcohol level higher than the legal limit contributed to a significant number of these fatalities.     

San Francisco pedestrian injury surveillance: mapping, under-reporting, and injury severity in police and hospital records

GOALS: Police reports of severely injured pedestrians help identify hazardous traffic areas in San Francisco, but they under-report non-fatal collisions. We set out to: identify injured pedestrians who were missing from police collision reports, see what biases exist in injury reporting and assess the utility of broad categories of police severe injury (including fatal) for mapping and analysis. METHODS: We linked data on injured pedestrians from police collision reports listed in the Statewide Integrated Traffic Reporting System (SWITRS, n = 1991) with records of pedestrians treated at San Francisco General Hospital (SFGH, n = 1323) for 2000 and 2001. Data were analyzed using bivariate statistics, logistic regression and mapping. RESULTS: : We found that police collision reports underestimated the number of injured pedestrians by 21% (531/2442). Pedestrians treated at SFGH who were African-American were less likely then whites (odds ratio = 0.55, p-value < or= 0.01), and females were more likely than males (odds ratio = 1.5, p-value < or = 0.01) to have a police collision report. Over 70% of pedestrians deemed by the police to have a severe injury received treatment at SFGH, regardless of the collision's distance from SFGH. The sensitivity of a police-designated severe injury (including fatal) was 69% and the specificity was 89% when compared with a known SFGH assessment. But, sensitivity declined when we included pedestrians without a SFGH record. CONCLUSION: Though collision reports have demonstrated limitations, broad categories of police severity may be sensitive enough to map locations where numerous severe injuries occur, for timely countermeasure selection.     

Traffic volume and collisions involving transit and nontransit vehicles.

This study reports an analysis of collisions occurring between public transit vehicles operated by the San Francisco Municipal Railway System (Muni), the public transit agency for the City of San Francisco, and nontransit vehicles. The analysis, focusing on weekday collisions during 1987, demonstrated a strong association between hourly transit collisions rates and hourly traffic volume. The collision rate varied from 0.01 per 1,000 Muni vehicle-hours of operation during the interval 5 A.M. to 6 A.M., a time of very low traffic volume, to 0.93 (approximately 1 collision per 1,000 Muni vehicle-hours of operation) during the interval 5 P.M. to 6 P.M., a time of very high traffic volume. Using a power function to predict either the total number of collisions, or the rate of collisions per 1,000 Muni vehicle-hours, almost 90% of total variation was accounted for by traffic volume. A very similar pattern was found for collisions judged either avoidable or unavoidable. A peak in the collision rate between 2 A.M. and 3 A.M. could not be accounted for by traffic volume alone. That peak occurred in the one-hour interval following the 2 A.M. closing of bars in San Francisco, and was composed entirely of a sharp increase in unavoidable collisions. Increasing traffic volume appeared to operate through two mechanisms: (i) an increase in the number of opportunities for a collision, defined as a quantity proportional to the product of the number of Muni and non-Muni vehicles; (ii) an increase in the probability of a collision occurring between any given pair of vehicles.     

Active transportation: Do current traffic safety policies protect non-motorists?

Objective

This study investigated the impact that state traffic safety regulations have on non-motorist fatality rates.

Methods

Data obtained from the National Highway Traffic Safety Administration (NHTSA), the Federal Highway Administration (FHWA), and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) were analyzed through a pooled time series cross-sectional model using fixed effects regression for all 50 states from 1999 to 2009. Two dependent variables were used in separate models measuring annual state non-motorist fatalities per million population, and the natural log of state non-motorist fatalities. Independent variables measuring traffic policies included state expenditures for highway law enforcement and safety per capita; driver cell phone use regulations; graduated driver license regulations; driver blood alcohol concentration regulations; bike helmet regulations; and seat belt regulations. Other control variables included percent of all vehicle miles driven that are urban and mean per capita alcohol consumption per year.

Results

Non-motorist traffic safety was positively impacted by state highway law enforcement and safety expenditures per capita, with a decrease in non-motorist fatalities occurring with increased spending. Per capita consumption of alcohol also influenced non-motorist fatalities, with higher non-motorist fatalities occurring with higher per capita consumption of alcohol. Other traffic safety covariates did not appear to have a significant impact on non-motorist fatality rates in the models.

Conclusion

Our research suggests that increased expenditures on state highway and traffic safety and the initiation/expansion of programs targeted at curbing both driver and non-motorist intoxication are a starting point for the implementation of traffic safety policies that reduce risks for non-motorists.     

The effect of Operation 24 Hours on reducing collision in the City of Edmonton

In the City of Edmonton, in order to reduce the prevalence of collisions, the Operation 24 Hours program (OPS24) was developed by using existing police and transportation services resources. The program uses traditional manned police speed enforcement method, which are supplemented by traffic safety messages displayed on permanent and mobile dynamic messaging signs (DMS). In this paper, collision data analysis was performed by looking at the daily number of collisions from 2008 to 2011 that covers 28 Operation 24 Hours (OPS24) events. The objective of the collision data analysis is to analyze if there is a reduction in collision frequencies after OPS24 was held and examined how long the collision reduction effect last. Weather factors such as temperature, thickness of snow, and wind gust have been considered by many as a great influence on collision occurrences, especially in a city with long and cold winter such as Edmonton. Therefore, collision modeling was performed by considering these external weather factors. To analyze the linear and periodic trend of different collision types (injury, fatal, and property damage only (PDO)) and examine the influence of weather factors on collisions, negative binomial time series model that accounts for seasonality and weather factors was used to model daily collision data. The modeling also considered collision proportion to account for missing traffic volume data; the Gaussian time series model that accounts for seasonality and weather factors was used to model collision proportion. To estimate the collision trend and test for changes in collision levels before/after OPS24, interrupted time series model with segmented regression was used. While for estimating how long the effect of the OPS24 last, change point method was applied.     

Exploring the impact of a dedicated streetcar right-of-way on pedestrian motor vehicle collisions: A quasi experimental design

Background and Objectives

The frequency of pedestrian collisions is strongly influenced by the built environment, including road width, street connectivity and public transit design. In 2010, 2159 pedestrian collisions were reported in the City of Toronto, Canada with 20 fatalities. Previous studies have reported that streetcars operating in mixed traffic pose safety risks to pedestrians; however, few studies evaluate the effects on pedestrian-motor vehicle collisions (PMVC). The objective of this study was to examine changes in the rate and spatial patterning of PMVC, pre to post right-of-way (ROW) installation of the St. Clair Avenue West streetcar in the City of Toronto, Canada.

Methods

A quasi-experimental design was used to evaluate changes in PMVC rate, following implementation of a streetcar ROW. Collision data were extracted from all police-reported PMVC, complied and verified by the City of Toronto, from January 1, 2000 to December 31, 2011. A zero-inflated Poisson regression analysis estimated the change in PMVC, pre to post ROW. Age and injury severity were also examined. Changes in the spatial pattern of collisions were examined by applying the G function to describe the proportion of collision events that shared a nearest neighbor distance less than or equal to a threshold distance.

Results

A total of 23,607 PMVC occurred on roadways during the study period; 441 occurring on St. Clair Ave, 153 during the period of analysis. There was a 48% decrease in the rate of collisions on St. Clair [Incidence rate ratio (IRR) = 0.52, 95% CI: 0.37–0.74], post ROW installation. There were also decreases noted for children (IRR = 0.13, 95% CI: 0.04–0.44), adults (IRR = 0.61, 95% CI: 0.38–0.97), and minor injuries (IRR = 0.56, 95% CI: 0.40–0.80). Spatial analyses indicated increased dispersion of collision events across each redeveloped route segment following the changes in ROW design.

Conclusions/Implications

Construction of a raised ROW operating on St. Clair Ave. was associated with a reduction in the rate of collisions. Differences in pre- and post collision spatial structure indicated changes in collision locations. Results from this study suggest that a streetcar ROW may be a safer alternative for pedestrians compared to a mixed traffic streetcar route and should be considered by city planners where appropriate to the street environment.     

Visual assessment of pedestrian crashes

Of the numerous factors that play a role in fatal pedestrian collisions, the time of day, day of the week, and time of year can be significant determinants. More than 60% of all pedestrian collisions in 2007 occurred at night, despite the presumed decrease in both pedestrian and automobile exposure during the night. Although this trend is partially explained by factors such as fatigue and alcohol consumption, prior analysis of the Fatality Analysis Reporting System database suggests that pedestrian fatalities increase as light decreases after controlling for other factors.This study applies graphical cross-tabulation, a novel visual assessment approach, to explore the relationships among collision variables. The results reveal that twilight and the first hour of darkness typically observe the greatest frequency of pedestrian fatal collisions. These hours are not necessarily the most risky on a per mile travelled basis, however, because pedestrian volumes are often still high. Additional analysis is needed to quantify the extent to which pedestrian exposure (walking/crossing activity) in these time periods plays a role in pedestrian crash involvement. Weekly patterns of pedestrian fatal collisions vary by time of year due to the seasonal changes in sunset time. In December, collisions are concentrated around twilight and the first hour of darkness throughout the week while, in June, collisions are most heavily concentrated around twilight and the first hours of darkness on Friday and Saturday. Friday and Saturday nights in June may be the most dangerous times for pedestrians. Knowing when pedestrian risk is highest is critically important for formulating effective mitigation strategies and for efficiently investing safety funds. This applied visual approach is a helpful tool for researchers intending to communicate with policy-makers and to identify relationships that can then be tested with more sophisticated statistical tools.     

An analysis of Malaysia road traffic death distribution by road environment

Various initiatives, strategies and programmes have been taken by the Government of Malaysia to resolve issues pertaining to road traffic deaths. Nevertheless, the implementation of the programmes outlined in Malaysian Road Safety Plan 2006 needs to be enhanced in order to achieve the set targets. In this regard, it is imperative for all parties concerning road safety to determine the factors that significantly contribute to road traffic deaths. According to the Ministry of Works, Malaysia, the blackspot treatment programme (which is centred on the elimination of road hazards by engineering approaches) is successful in reducing the number of injuries due to road traffic accidents up to a certain extent. This study is focussed on analysing road traffic deaths caused by various road environment elements recorded by the police from 2000 to 2011 in order to determine their distribution, proportion and relationship with fatal accidents. The Chi-square test and Marascuilo procedure with 5% level of significance are used in this study. Based on locality, the number of road traffic deaths in rural area (66%) is significantly higher compared with that in urban areas (34%). Based on road category, the number of road traffic deaths is the highest for federal roads, whereas the highest rate of fatalities per kilometre is recorded for expressways. Based on road segment, the number of road traffic deaths is the highest for straight road segments, followed by bends. In addition, the number of road traffic deaths is the highest for Y/T junctions, followed by cross junctions. The lowest number of road traffic deaths is recorded for interchanges and roundabouts. The results show that only 11.25% of the total road traffic deaths are related to road defects. The highest proportion of deaths due to road defects (48.6%) is associated with lack of street lighting provision, whereas road shoulder edge drop-off and potholes contribute 15.4% and 11.2% of road traffic deaths, respectively.