Passenger carriage and car crash injury: a comparison between younger and older drivers

This study was conducted to investigate the effects of passenger carriage, including the number of passengers and the ages of passengers, on the risk of car crash injury. The study utilised data obtained from a case–control study conducted in the Auckland region of New Zealand between 1998 and 1999. Cases were car drivers who involved in crashes in which at least one occupant was hospitalised or killed. Controls were selected from a cluster random sample of car drivers on the roads in the same region. Self-report information on the numbers of passengers carried and their ages at the time of crash or at the time of the roadside survey, as well as potential confounding factors, was obtained from the drivers, or a proxy, using an interviewer-administered questionnaire. A total of 571 cases (93% response rate), including 195 younger drivers (aged <25 years), and 588 controls (79% response rate), including 94 younger drivers participated in the study. After adjusting for other risk factors, the odds of car crash injury among younger drivers was 15.55 times (95% CI 5.76–42.02) for those who carried two or more same age passengers, and 10.19 times (95% CI 2.84–36.65) for those who carried two or more other age passengers, compared with unaccompanied drivers. In comparison, no increase in risk was observed for older drivers who carried two or more passengers regardless of age. The carriage of two or more passengers, irrespective of the ages of passengers, significantly increases the risk of car crash injury among younger drivers. Passenger restriction as part of the graduate licensing system was discussed in the light of these results.     

Suicidal ideation, antidepressive medication and car crash injury

OBJECTIVE: This study aimed to investigate the association between suicidal ideation, antidepressive medication and the risk of a car crash resulting in serious injury. DESIGN: This was a population-based case-control study. Cases were car drivers who were involved in crashes in which at least one occupant of their car was hospitalised or killed. Controls were selected using a cluster random sample of car drivers on the roads in the same region. Self-reported information on suicidal ideation in the 12 months prior to the crash or roadside survey, current usage of antidepressive medication as well as other crash-related risk factors was obtained from the drivers, or by proxy, using an interviewer-administered questionnaire. SETTING: The study was conducted in the Auckland region of New Zealand in 1998 and 1999. RESULTS: There was a significant association between drivers who had suicidal ideation but without current antidepressive medication and the risk of an injury crash (OR=4.16, 95% CI=2.14-8.10), when compared to drivers without any suicidal ideation. CONCLUSION: The risk of an injury crash was significantly increased for those drivers who reported to have previous or current suicidal ideation but without current antidepressant medication.     

Factors associated with young drivers' car crash injury: comparisons among learner,provisional, and full licensees

This exploratory study aimed to investigate factors associated with car crash injury among young drivers aged <25 years with different license status. Of special interest were the differences in risk patterns among different license holders of different age groups. Data utilised in this study were obtained from the New South Wales (NSW) police. The results indicated that female young drivers were more at risk of being killed or injured in a crash than males. Some risk factors, in particular environment-related factors, were identified as license-status-and-age specific. On the contrary, disregarding their driving experiences and ages, young drivers were more influenced by their own behaviours and driving conditions. Young drivers of 16–17 years with learner and provisional licenses tended to have increased risk of crash injury due to special road features. Night-time driving seemed to be a problem for older and more experienced drivers only. Fully licensed drivers of 18–19 and 20–24 years were more susceptible to the influence of alcohol. Risk-taking, speeding, fatigue, and carrying many passengers increased the risk of crash injury to car occupants for nearly all young drivers disregarding their ages and driving experiences. The results obtained provided indicative information on areas where the graduated licensing systems in NSW might be effective, and on other areas that might be lacking. A population-based case-control study was proposed to overcome the limitations of this study.     

The contribution of passengers versus mobile phone use to motor vehicle crashes resulting in hospital attendance by the driver

There is evidence that mobile phone use while driving (including hands-free) is associated with motor vehicle crashes. However, whether the effects of mobile phone use differ from that of passengers in the vehicle remains unclear. The aim of this research was to estimate the risk of crash associated with passenger carriage and compare that with mobile phone use. A case-control study (‘passenger study’) was performed in Perth, Western Australia in 2003 and 2004. Cases were 274 drivers who attended hospital following a motor vehicle crash and controls were 1096 drivers (1:4 matching) recruited at service stations matched to the location and time and day of week of the crash. The results were compared with those of a case-crossover study (‘mobile phone study’) undertaken concurrently (n = 456); 152 cases were common to both studies. Passenger carriage increased the likelihood of a crash (adjusted odds ratio (adj. OR), 95% confidence interval (95% CI), 1.6, 1.1–2.2). Drivers carrying two or more passengers were twice as likely to crash as unaccompanied drivers (adj. OR 2.2, 95% CI 1.3–3.8). By comparison, driver's use of a mobile phone within 5 min before a crash was associated with a fourfold increased likelihood of crashing (OR 4.1, 95% CI 2.2–7.7). Passenger carriage and increasing numbers of passengers are associated with an increased likelihood of crash, though not to the same extent as mobile phone use. Further research is needed to investigate the factors underlying the increased risks.     

A different perspective on conspicuity related motorcycle crashes

The most common type of conflict in which a motorcyclist is injured or killed is a collision between a motorcycle and a car, often in priority situations. Many studies on motorcycle safety focus on the question why car drivers fail to give priority and on the poor conspicuity of motorcycles. The concept of ‘looked-but-failed-to-see’ crashes is a recurring item. On the other hand, it is not entirely unexpected that motorcycles have many conflicts with cars; there simply are so many cars on the road. This paper tries to unravel whether – acknowledging the differences in exposure – car drivers indeed fail to yield for motorcycles more often than for other cars. For this purpose we compared the causes of crashes on intersections (e.g. failing to give priority, speeding, etc.) between different crash types (car–motorcycle or car–car). In addition, we compared the crash causes of dual drivers (i.e. car drivers who also have their motorcycle licence) with regular car drivers. Our crash analysis suggests that car drivers do not fail to give priority to motorcycles relatively more often than to another car when this car/motorcycle approaches from a perpendicular angle. There is only one priority situation where motorcycles seem to be at a disadvantage compared to cars. This is when a car makes a left turn, and fails to give priority to an oncoming motorcycle. This specific crash scenario occurs more often when the oncoming vehicle is a motorcycle than when it is a car. We did not find a significant difference between dual drivers and regular car drivers in how often they give priority to motorcycles compared to cars.     

Analysis of crash parameters and driver characteristics associated with lower limb injury

This study aims to investigate changes in frequency, risk, and patterns of lower limb injuries due to vehicle and occupant parameters as a function of vehicle model year. From the National Automotive Sampling System-Crashworthiness Data System, 10,988 observations were sampled and analyzed, representing 4.7 million belted drivers involved in frontal crashes for the years 1998–2010.A logistic regression model was developed to understand the association of sustaining knee and below knee lower limb injuries of moderate or greater severity with motor vehicle crash characteristics such as vehicle type and model years, toepan and instrument panel intrusions in addition to the occupant’s age, gender, height and weight. Toepan intrusion greater than 2 cm was significantly associated with an increased likelihood of injury (odds ratio: 9.10, 95% confidence interval 1.82–45.42). Females sustained a higher likelihood of distal lower limb injuries (OR: 6.83, 1.56–29.93) as compared to males. Increased mass of the driver was also found to have a positive association with injury (OR: 1.04, 1.02–1.06), while age and height were not associated with injury likelihood. Relative to passenger cars, vans exhibited a protective effect against sustaining lower limb injury (OR: 0.24, 0.07–0.78), whereas no association was shown for light trucks (OR: 1.31, 0.69–2.49) or SUVs (OR: 0.76, 0.28–2.02).To examine whether current crash testing results are representative of real-world NASS-CDS findings, data from frontal offset crash tests performed by the Insurance Institute for Highway Safety (IIHS) were examined. IIHS data indicated a decreasing trend in vehicle foot well and toepan intrusion, foot accelerations, tibia axial forces and tibia index in relation to increasing vehicle model year between the year 1995 and 2013. Over 90% of vehicles received the highest IIHS rating, with steady improvement from the upper and lower tibia index, tibia axial force and the resultant foot acceleration considering both left and right extremities. Passenger cars received the highest rating followed by SUVs and light trucks, while vans attained the lowest rating.These results demonstrate that while there has been steady improvement in vehicle crash test performance, below-knee lower extremity injuries remain the most common AIS 2+ injury in real-world frontal crashes.     

Relative risk of injury and death in ambulances and other emergency vehicles

This study addresses of the impacts of emergency vehicle (ambulances, police cars and fire trucks) occupant seating position, restraint use and vehicle response status on injuries and fatalities. Multi-way frequency and ordinal logistic regression analyses were performed on two large national databases, the National Highway Traffic Safety Administration’s Fatality Analysis Reporting System (FARS) and the General Estimates System (GES). One model estimated the relative risk ratios for different levels of injury severity to occupants traveling in ambulances. Restrained ambulance occupants involved in a crash were significantly less likely to be killed or seriously injured than unrestrained occupants. Ambulance rear occupants were significantly more likely to be killed than front-seat occupants. Ambulance occupants traveling non-emergency were more likely than occupants traveling emergency to be killed or severely injured. Unrestrained ambulance occupants, occupants riding in the patient compartment and especially unrestrained occupants riding in the patient compartment were at substantially increased risk of injury and death when involved in a crash. A second model incorporated police cars and fire trucks. In the combined ambulance–fire truck–police car model, the likelihood of an occupant fatality for those involved in a crash was higher for routine responses. Relative to police cars and fire trucks, ambulances experienced the highest percentage of fatal crashes where occupants are killed and the highest percentage of crashes where occupants are injured. Lack of restraint use and/or responding with ‘lights and siren’ characterized the vast majority of fatalities among fire truck occupants. A third model incorporated non-special use van and passenger car occupants, which otherwise replicated the second model. Our findings suggest that ambulance crewmembers riding in the back and firefighters in any seating position, should be restrained whenever feasible. Family members accompanying ambulance patients should ride in the front-seat of the ambulance.     

Serious or fatal driver injury rate versus car mass in head-on crashes between cars of similar mass

This work was performed to determine relations between car mass and driver injuries (serious or fatal) when cars of similar mass crash into each other head-on. This type of crash is examined because it is considered similar in some respects to a barrier crash. Data from the United States Fatal Accident Reporting System (FARS) are used to examine driver fatality likelihood as a function of car mass when cars of similar mass crash into each other. Pedestrian fatalities involving cars of the same mass are used to estimate exposure. Two additional sources of data (State data from North Carolina and New York) are used to generate information on the number of drivers seriously injured or killed per police reported crash when cars of similar mass crash into each other. The present study finds that the likelihood of driver injury (fatal or serious) when cars of similar mass crash into each other increases with decreasing car mass, both for head-on crashes and for crashes in all directions. The study does not address possible mechanisms that might lead to such relations. All the data analyzed reveal a fairly consistent picture--a driver in a 900 kg car crashing head-on into another 900 kg car is about 2.0 times as likely to be seriously injured or killed as is a driver of a 1800 kg car crashing head-on into another 1800 kg car.     

The independent contribution of driver,crash, and vehicle characteristics to driver fatalities

Several driver, crash, and vehicle characteristics may affect the fatality risk of drivers involved in crashes. To determine the independent contribution of these variables to drivers’ fatality risk, we used data from single-vehicle crashes with fixed objects contained in the US Fatal Accident Reporting System. A multivariate logistic regression revealed that the odds ratio (OR) of a fatal injury increased with age, reaching 4.98 (99% confidence interval (CI)=2.01–12.37) for drivers aged 80+ compared with drivers aged 40–49 years. Female gender (OR=1.54, 99% CI=1.35–1.76) and blood alcohol concentration greater than 0.30 (OR=3.16, 99% CI=1.96–5.09) were also associated with higher fatality odds. In comparison with front impacts, driver-side impacts doubled the odds of a fatality (OR=2.26, 99% CI=1.92–2.65), and speeds in excess of 111 kilometers per hour (kph; 69 mph) prior to or at impact were related to higher fatality odds (OR=2.64, 99% CI=1.82–3.83) compared with speeds of less than 56 kph (35 mph). Three-point seatbelts were protective against fatal injuries (OR=0.46, 99% CI=0.39–0.53 compared with no belt). These data suggest that increasing seatbelt use, reducing speed, and reducing the number and severity of driver-side impacts may prevent fatalities. The importance of age and gender suggests that the specific safety needs of older drivers and female drivers may need to be addressed separately from those of men and younger drivers.     

Modelling crash propensity of carshare members

Carshare systems are considered a promising solution for sustainable development of cities. To promote carsharing it is imperative to make them cost effective, which includes reduction in costs associated to crashes and insurance. To achieve this goal, it is important to characterize carshare users involved in crashes and understand factors that can explain at-fault and not-at fault drivers. This study utilizes data from GoGet carshare users in Sydney, Australia. Based on this study it was found that carshare users who utilize cars less frequently, own one or more cars, have less number of accidents in the past ten years, have chosen a higher insurance excess and have had a license for a longer period of time are less likely to be involved in a crash. However, if a crash occurs, carshare users not needing a car on the weekend, driving less than 1000 km in the last year, rarely using a car and having an Australian license increases the likelihood to be at-fault. Since the dataset contained information about all members as well as not-at-fault drivers, it provided a unique opportunity to explore some aspects of quasi-induced exposure. The results indicate systematic differences in the distribution between the not-at-fault drivers and the carshare members based on the kilometres driven last year, main mode of travel, car ownership status and how often the car is needed. Finally, based on this study it is recommended that creating an incentive structure based on training and experience (based on kilometres driven), possibly tagged to the insurance excess could improve safety, and reduce costs associated to crashes for carshare systems.     

Factors associated with fatal and injurious car crash among learner drivers in New South Wales,Australia

This exploratory study investigated factors associated with car crash injury among learner drivers across difference ages by using data routinely collected by the NSW police. The results obtained indicated that some factors are commonly associated with car crash injury across nearly all ages. On the other hand, some others are more age specific. On the whole, female learner drivers were more at risk of being killed or injured as compared to males. The drivers of 16 years old had an increased risk of crash injury due to environmental factors, such as special road feature, and distraction outside the vehicle. The increased risk of crash injury for older drivers (> or =25 years) was associated with distractions from both inside and outside vehicle. Night time driving posed a special risk to learner drivers aged 20-24 years old, but not other age groups. Speeding was a common factor for the increased risk of crash injury across all age groups. The implication of the results and limitations of the study were discussed.     

Overall injury risk to different drivers: combining exposure,frequency, and severity models

Traffic crash risk assessments should incorporate appropriate exposure data. However, existing US nationwide crash data sets, the NASS General Estimates System (GES) and the Fatality Analysis Reporting System (FARS), do not contain information on driver or vehicle exposure. In order to obtain appropriate exposure data, this work estimates vehicle miles driven (VMD) by different drivers using the Nationwide Personal Transportation Survey (NPTS). These results are combined with annual crash rates and injury severity information from the GES for a comprehensive assessment of overall risk to different drivers across vehicle classes.Data are distinguished by driver age, gender, vehicle type, crash type (rollover versus non-rollover), and injury severity. After correcting for drivers' crash exposure, results indicate that young drivers are far more crash prone than other drivers (per VMD) and that drivers of sports utility vehicles (SUVs) and pickups (PUs) are more likely to be involved in rollover crashes than those driving passenger cars. Although, the results suggest that drivers of SUVs are generally much less crash prone than drivers of passenger cars, the rollover propensity of SUVs and the severity of that crash type offset many of the incident benefits for SUV drivers.     

Injury trends of passenger car drivers in frontal crashes in the USA

Injuries trends of passenger car drivers in head-on collisions are identified based on crash data extracted from the National Automotive Sampling System. Annual injury incidence levels are estimated for years 1990-2007. Over that period, the number of crashes is predicted to rise by 71%. However, the number of serious injuries to drivers is expected to rise by only 41% and driver fatalities are anticipated to decrease by 9%. Meantime, the types of injuries suffered by drivers are changing. Year-to-year shifts in injury patterns result from changes in vehicle size classes within the US vehicle fleet population and increases in seat belt use and air bag availability. The effectiveness of air bags in saving lives is estimated to be 30%, and with more air bag-equipped cars on the road, the probability of sustaining a life-threatening head or a torso injury is reduced. Air bags, however, are not as effective in preventing upper and lower extremity injuries, and thus arm and leg injuries will become more prevalent in years to come.     

Paediatric slow-speed non-traffic fatalities: Victoria, Australia, 1985–1995

An important group of fatal incidents are slow-speed pedestrian non-traffic incidents to children, which account for 14% of accidental deaths from all causes in Victorian children under 5 years of age between 1985 and 1995, and 12% of pedestrian deaths of all ages. In Victoria, Australia, the database of the state Consultative Council on Obstetric and Paediatric Morbidity and Mortality was utilised to identify paediatric slow-speed pedestrian non-traffic-accident deaths in the local population. Additional data relating to the car and its driver, the child, and the circumstances of the incident were abstracted from records kept by the State Coroner and the Victorian compulsory third party traffic injury insurance organisation. Twenty eight Victorian children were identified who had died in one of three types of incident (driverless cars, child interacting with the vehicle and driver, and drivers who were unaware of the child's proximity). These incidents were more common in rural areas compared with urban, usually occurring at the child's home. The child was with or near an adult on all occasions. The vehicle was usually being driven by a relative, and was reversing in a higher proportion of ‘unaware’ incidents compared with the ‘interactive’ type. The association of ‘off-road’ family vehicles and trucks with these incidents appears to be increasing, especially in recent years. These findings suggest some countermeasures, including the separation of vehicle driveways from children's play areas, and object vicinity ultrasonic warning devices for vehicles.     

Evolution of the crashworthiness and aggressivity of the Spanish car fleet

This paper investigates the relationship between a passenger car's year of registration and its crashworthiness and aggressivity in real-world crashes. Crashworthiness is defined as the ability of a car to protect its own occupants, and has been evaluated in single and two-car crashes. Aggressivity is defined as the ability to protect users travelling in other vehicles, and has been evaluated only in two-car crashes. The dependent variable is defined as the proportion of injured drivers who are killed or seriously injured; following previous research, we refer to this magnitude as injury severity. A decrease in the injury severity of a driver is interpreted as an improvement in the crashworthiness of their car; similarly, a decrease in the injury severity of the opponent driver is regarded as an improvement in aggressivity.Data have been extracted from the Spanish Road Accident Database, which contains information on every accident registered by the police in which at least one person was injured. Two types of regression models have been used: logistic regression models in single-car crashes, and generalised estimating equations (GEE) models in two-car crashes. GEE allow to take account of the correlation between the injury severities of drivers involved in the same crash. The independent variables considered have been: year of registration of the subject car (crashworthiness component), year of registration of the opponent car (aggressivity component), and several factors related to road, driver and environment.Our models confirm that crashworthiness has largely improved in two-car crashes: when crashing into the average opponent car, drivers of cars registered before 1985 have a significantly higher probability of being killed or seriously injured than drivers of cars registered in 2000–2005 (odds ratio: 1.80; 95% confidence interval: 1.61; 2.01). In single-car crashes, the improvement in crashworthiness is very slight (odds ratio: 1.04; 95% confidence interval: 0.93; 1.16). On the other hand, we have also found a significant worsening in aggressivity in two-car crashes: the driver of the average car has a significantly lower probability of being killed or seriously injured when crashing into a car registered before 1985, than when crashing into a car registered in 2000–2005 (odds ratio: 0.52; 95% confidence interval: 0.45; 0.60).Our results are consistent with a large amount of previous research that has reported significant improvements in the protection of car occupants. They also add to some recent studies that have found a worsening in the aggressivity of modern cars. This trend may be reflecting the impact of differences in masses and travel speeds, as well as the influence of consumer choices. The precise reasons have to be investigated. Also, the causes have to be found for so large a discrepancy between crashworthiness in single and two-car crashes.     

Hearing loss and automobile airbag deployments

In an on-going research program, on the causation of injuries in motor vehicle accidents, at the University of Michigan Transportation Research Institute, crashes with airbags have been, and are continuing to be, investigated. In order to determine the occurrence, if any, of ‘hearing problems’ associated with airbag deployments, drivers and passengers who had been involved in ‘airbag’ automobile crashes were interviewed by telephone. From the crashes investigated, 225 attempts were made to contact drivers who were exposed to airbag deployments. From these telephone interviews, contacts were made with 177 car occupants. Only three reported that they had experienced any type of hearing-related problems subsequent to their crash. One other case is reported of a driver who had pre-crash hearing loss. It appears that permanent hearing deficit due to airbag deployment, both in cars with the steering wheel airbag alone, and in those with a passenger side airbag, is an infrequent event (1.7%) from the data of this study.     

The influence of passengers on the risk of the driver causing a car collision in Spain. Analysis of collisions from 1990 to 1999

Objective: To determine how the number of passengers, their age and their sex influence the risk of different types of Spanish drivers causing a collision between two or more cars.Methods: We selected, from the Spanish database of traffic crashes resulting in personal injuries or death, those collisions between two or more cars that occurred between 1990 and 1999 in which only one of the involved drivers committed a driving infraction. These drivers were considered the cases; non-infractor drivers were considered their matched controls. We collected information on the number, age and sex of the passengers in each vehicle, along with some potential confounding variables of the drivers and the vehicles involved. Crude and adjusted odds ratios were calculated for the main categories of driver and passenger.Results: A protective effect for the presence of passengers was detected (adjusted odds ratio: 0.69; 95% CI: 0.67-0.70). The protective effect was higher for drivers aged more than 45 years and lower for the youngest drivers (<24 years old). The strongest association was observed for female passengers who accompanied male drivers. The protective effect was lower for passengers older than 64 years.Conclusion: Our results suggest that drivers are less likely to cause a car collision between two or more cars that results in personal injuries or death when they are accompanied by passengers, regardless of driver or passenger characteristics.     

Relative fatality risk in different seating positions versus car model year

Fatality risk of drivers compared to right-front passengers is examined vs. car model year (MY) using Fatal Accident Reporting System (FARS) data for 1975 through 1986. Confounding effects are removed by comparing unrestrained occupants matched in sex and age (to within three years). MY ≥ 1968 cars, which complied with Federal Motor Vehicle Standard 203 (impact protection for the driver) and FMVSS 204 (rearward column displacement), are compared to MY ≤ 1966 cars, which did not comply with these standards. It is found that, compared to right-front passengers in the same cars, drivers had higher relative fatality risks in MY ≥ 1968 cars and lower relative fatality risks in MY ≤ 1966 cars. Because there are so few fatal frontal crash data for MY 1966 and MY 1968 cars, definitive conclusions regarding the effectiveness of FMVSS 203 and 204 in reducing driver fatalities are not possible. However, our analysis, together with the assumption that right-front-passenger fatality risk was the same in 1966 and 1968 MY cars, does suggest that a previous 12% effectiveness estimate is more likely to be high than low.     

Crash protectiveness to occupant injury and vehicle damage: An investigation on major car brands

This study sets out to investigate vehicles’ crash protectiveness on occupant injury and vehicle damage, which can be deemed as an extension of the traditional crash worthiness. A Bayesian bivariate hierarchical ordered logistic (BVHOL) model is developed to estimate the occupant protectiveness (OP) and vehicle protectiveness (VP) of 23 major car brands in Florida, with considering vehicles’ crash aggressivity and controlling external factors. The proposed model not only takes over the strength of the existing hierarchical ordered logistic (HOL) model, i.e. specifying the order characteristics of crash outcomes and cross-crash heterogeneities, but also accounts for the correlation between the two crash responses, driver injury and vehicle damage. A total of 7335 two-vehicle-crash records with 14,670 cars involved in Florida are used for the investigation. From the estimation results, it's found that most of the luxury cars such as Cadillac, Volvo and Lexus possess excellent OP and VP while some brands such as KIA and Saturn perform very badly in both aspects. The ranks of the estimated safety performance indices are even compared to the counterparts in Huang et al. study [Huang, H., Hu, S., Abdel-Aty, M., 2014. Indexing crash worthiness and crash aggressivity by major car brands. Safety Science 62, 339–347]. The results show that the rank of occupant protectiveness index (OPI) is relatively coherent with that of crash worthiness index, but the ranks of crash aggressivity index in both studies is more different from each other. Meanwhile, a great discrepancy between the OPI rank and that of vehicle protectiveness index is found. What's more, the results of control variables and hyper-parameters estimation as well as comparison to HOL models with separate or identical threshold errors, demonstrate the validity and advancement of the proposed model and the robustness of the estimated OP and VP.     

Accident involvement and crash injury rates: An investigation by make, model and year of car

Accident involvement and crash injury rates per million miles of vehicle travel are estimated by make, model and year of car. The accident and injury information was obtained from the North Carolina accident files, while exposure data were derived from paired odometer readings recorded on a statewide sample of motor vehicle inspection receipts.

The resulting estimates show a steady decrease in annual mileage with vehicle age. For the newer model years, large cars have generally higher annual mileages than small cars, and station wagons higher mileages than sedans or hardtops. The accident involvement and injury rates decline for the newer model cars, especially for larger-sized cars. Full-sized cars have the lowest overall accident and injury rates. Among standard-sized cars, two-door cars have higher accident and injury rates than four-door cars, and hardtops higher than sedans or station wagons.