Driver Side Research Articles

Occupational noise exposure of operators of heavy trucks.

Over 400 measurements were taken across Canada to assess the noise exposure of truck operators. The exposure of the driver was evaluated using both 3-dB (Leq) and 5-dB (L5dB) exchange rates. Driving with windows closed and radio not operating resulted in the lowest exposure. The drivers' Leq ranged from 78 to 89 dBA, with a mean of 82.7 dBA; operating the radio increased the mean by 2.8 dB; driving with the driver's side window open increased the mean exposure by 1.3 dB; and driving with the window open and operating the radio resulted in an increase of 3.9 dB. Trucks with cabs mounted over the engine appear to be quieter than standard trucks by about 2.6 dB. Operations on four-lane highways are 1.6 dB noisier than on two-lane highways, most likely as a result of higher speeds on the former. Long haul (city-to-city) operations on hilly terrain appear to be quieter than on flat terrain by about 2.2 dB, again probably indicating the strong effect of speed. Regression analysis was used to obtain relationships between a number of variables such as Leq and L5dB, etc. These measurements indicate that the exposure of a driver is almost certain to exceed the current threshold limit value for noise (85 dBA for 8 hours with a 3-dB exchange rate) when driving with the radio on and the driver's side window open. Comparable numbers in terms of L5dB are also reported.

The Cost-effectiveness of Air Bags by Seating Position

Motor vehicle crashes continue to cause significant mortality and morbidity in the United States. Installation of air bags in new passenger vehicles is a major initiative in the field of injury prevention. To assess the net health consequences and cost-effectiveness of driver's side and front passenger air bags from a societal perspective, taking into account the increased risk to children who occupy the front passenger seat and the diminished effectiveness for older adults. A deterministic state transition model tracked a hypothetical cohort of new vehicles over a 20-year period for 3 strategies: (1) installation of safety belts, (2) installation of driver's side air bags in addition to safety belts, and (3) installation of front passenger air bags in addition to safety belts and driver's side air bags. Changes in health outcomes, valued in terms of quality-adjusted life-years (QALYs) and costs (in 1993 dollars), were projected following the recommendations of the Panel on Cost-effectiveness in Health and Medicine. US population-based and convenience sample data were used. Incremental cost-effectiveness ratios. Safety belts are cost saving, even at 50% use. The addition of driver's side air bags to safety belts results in net health benefits at an incremental cost of $24000 per QALY saved. The further addition of front passenger air bags results in an incremental net benefit at a higher incremental cost of $61000 per QALY saved. Results were sensitive to the unit cost of air bag systems, their effectiveness, baseline fatality rates, the ratio of injuries to fatalities, and the real discount rate. Both air bag systems save life-years at costs that are comparable to many medical and public health practices. Immediate steps can be taken to enhance the cost-effectiveness of front passenger air bags, such as moving children to the rear seat.

Auto safety advice

There has been increasing media coverage about the dangers of air bags when infants, small children, pregnant women and short stature drivers are placed in the front passenger seat. Although it is fitting that the public be aware of such risks, we are deeply concerned that the well-established benefits of air bags are being overlooked by this intense media coverage. Air bags are performing well overall. They saved an estimated 1,100 lives during 1986-1995. Driver side air bags in passenger cars reduce overall fatality risk by an estimated 11 percent, including a 30 percent reduction in fatalities in head-on crashes.

Initial Driver Avoidance Behavior and Reaction Time to an Unalerted Intersection Incursion

Initial driver avoidance behavior and reaction time to an unexpected intersection incursion was determined using a state-of-the-art motion-based driving simulator (Iowa Driving Simulator). The intersection used for the experiment was on a two-lane rural highway (55 mph speed limit) that controlled perpendicular (crossing) traffic by stop signs. The subject vehicle did not have to stop and had the right-of-way on the highway. At one of three possible start times, an intersecting vehicle began moving into the intersection in front of the subject vehicle. This incurring vehicle intersected from either the driver's left or right side. Ninety-six subjects participated in the study. Subjects in the shortest, most severe collision avoidance situation were significantly slower to react and equally likely to steer or release the accelerator pedal as the initial avoidance maneuver. Subjects in the longest, least severe collision avoidance situation often released the accelerator pedal and braked prior to steering. Gender differences are also discussed.

Injury pattern and severity in lateral motor vehicle collisions: a Canadian experience.

To determine the pattern and severity of injury and the outcome of front seat motor vehicle occupants after lateral impact crashes. Retrospective review undertaken in a Regional Trauma Unit (Sunnybrook Health Science Centre). Review of seriously injured front seat motor vehicle occupants admitted to a Regional Trauma Unit over a 46-month period (September 15, 1989, to July 15, 1993) for whom vehicle crash information and occupant seat belt use were known. Three hundred forty-eight front seat vehicle occupants were available for study; one hundred forty-one (41%) were involved in a lateral impact motor vehicle crash. Driver side lateral crashes (57%) were more common than passenger side impacts. Victims of lateral impact crashes had a significantly higher mean Injury Severity Score (25 compared with 20 for nonlateral crashes: p < 0.05), and the direction of impact was strongly associated with injury severity (p < 0.05). Lateral impact crashes resulted in substantially more significant chest (p < 0.01) and intra-abdominal (p < 0.0001) injuries. Type of injury was significantly different between the lateral and nonlateral impact groups for facial, chest, abdominal, and musculoskeletal injuries. The direction of impact in motor vehicle crashes is strongly associated with the pattern and severity of organ injuries. Further attention to automobile safety design is necessary to better protect occupants involved in lateral impact crashes.

Thoracic response and injury with belt, driver side airbag, and force limited belt restraint systems

Abstract The performance of belt, airbag, and force limited belt restraint systems for the driver were compared using frontal sled tests. Nine human cadaver and six dummy sled tests were conducted at 56 km/h using a test buck representing a mid-size vehicle. Subject instrumentation included upper and lower chestbands to measure local thoracic deformations and sternal and spinal accelerometers to record torso deceleration. Following the sled tests, radiographs and autopsy results were used to correlate cadaver injury with measured engineering parameters and dummy response. Chest compression, acceleration, change in curvature and Viscous Criteria were evaluated for all occupants. Occupant kinematics were determined from analysis of high speed film. Local differences in the chest loading behavior among the restraint systems were identified using the chestband contours. The results of the research indicate that improvements in thoracic occupant protection may be achieved with the use of force limited belt and pretensioner systems.

Air Bag-related Corneal Rupture After Radial Keratotomy

We studied a case of air bag-associated corneal rupture in a patient who had previously undergone radial keratotomy surgery. The patient was struck in the right eye when his driver's side air bag inflated during a low-speed collision. Inflation of the air bag resulted in rupture of the patient's right cornea. The rupture involved all but one of his old radial keratotomy wounds. Patients who have undergone radial keratotomy may be at increased risk for corneal rupture caused by air bag trauma. These patients may benefit by wearing protective eyewear while driving cars equipped with air bags.

A Fatality Associated with the Deployment of an Automobile Airbag

Airbags have become an increasingly accepted automobile safety feature that can reduce the morbidity and mortality associated with motor vehicle collisions. We present the following case report of an unusual fatality with multiple internal injuries from a minor mechanism motor vehicle collision. The cause of injuries was determined to be secondary to the deployment of a driver's side airbag without the concomitant use of a lap-shoulder belt.

Lead Contamination in Automobiles of Lead-Exposed Bridgeworkers

Abstract Occupational exposure to lead at construction sites during lead-based paint abatement has become a widely recognized problem in recent years. However, these exposures to lead may not be limited to the workplace. Lead may be carried away from work sites on workers' skin and clothing, resulting in para-occupational or “take-home” exposure to workers' families. An indicator of potential take-home exposure is the level of contamination in workers' automobiles. In a recent study of lead exposures during lead-based paint abatement at a bridge renovation site, dust samples were collected from the interiors of workers' automobiles using wipe and vacuum collection methods. Lead was present in each of the 27 automobiles that were sampled. High lead loadings were found on driver's side floors (geometric mean = 1900 μg/m2), armrests (1100 μg/m2), and steering wheels (240 μg/m2). Lead contamination inside automobiles did not appear to be associated with personal exposures to airborne lead in the work environm...

Cutting of Airbag Materials

There are currently two principle material types which are used in the manufacture of airbags. They are uncoated nylon (polyamide 66) and coated nylon. Two types of commonly used coatings are Silicone and Neoprene. In general, coated materials are used for driver's side airbags and side impact bags, while passenger side airbags are made from uncoated nylon materials. Different cutting methods are needed for the two different classifications of mate rials. Coated nylon can be cut with traditional mechanical tools such as dies or reci procating knife cutters, due principally to the fact that the coating prevents fraying. On the other hand, uncoated nylon must be cut with a hot tool, such as a laser to pre vent fraying; fraying could compromise the airbag integrity during deployment.

Retinal Hemorrhage Secondary Airbag-Related Ocular Trauma

A case is presented in which a driver, who was wearing a three-point restraint system, was involved in a collision that triggered deployment of the vehicle's driver's-side airbag. The victim complained of blurred vision after the crash and on examination was found to have suffered a retinal hemorrhage in his right eye. Since no other cause could be determined, his injury was considered to be a result of contact with the deploying airbag.

Physical and Chemical Characterization of Airbag Effluents

This paper describes a study aimed at characterizing the exposure to physical and chemical by-products from the deployment of airbag restraint systems. Specifically, the levels of particulates and the composition of gases and bag fabric speed were measured in the passenger compartment following deployment of either a driver's side or driver's side/passenger's side airbag system. A Fourier transform infrared analyzer (FTIR) and chemiluminescence analyzers were used for gas analysis, a cascade impactor and gravimetric filter measurements for aerosol determination and high-speed films to determine fabric speed. The measured gases were found to be within the recommended guidelines for human exposures, but no guidelines exist for particle exposures of this magnitude (150-220 mg/m3) but short duration. High-speed films were also taken of the deployments to obtain an estimate of the fabric speed as it leaves the module. The maximum average speed for both types of airbag was approximately 100 mph and in both cases average speeds ranged from lows near 50 mph to highs of over 200 mph.

Air and Knee Bolster Restraint System

Growing evidence from data base and laboratory studies demonstrates effective occupant protection with the airbag supplemental restraint and seatbelt restraint system. Concern that drivers of vehicles equipped with airbags may assume adequate protection without concomitant seatbelt use prompted the study of unbelted occupant behavior in frontal crashes. To evaluate the crash protection afforded unbelted drivers in airbag-equipped vehicles. Six laboratory sled tests were conducted with a production driver's side airbag and knee bolster restraint system but without a seatbelt restraint system. Four human cadavers and the Hybrid III dummy were used as occupants in 32 km/h and 48 km/h tests with a simulated mid-size vehicle. Head contact with the windshield/header region of the simulated vehicle and abdominal impingement on the lower rim of the steering wheel were noted in all tests. Autopsy examinations and radiographic images identified extensive spinal and thoracic trauma in addition to lower extremity and facial injuries. Injury Severity Scores were considered severe to critical for all occupants. The evidence suggests the need to emphasize the use of seatbelts in conjunction with airbags and to develop a redesigned airbag and knee bolster system to control occupant kinematics and loading more effectively.

Restraint effectiveness, availability and use in fatal crashes: implications to injury control.

The effectiveness and benefits of occupant restraint systems are compared by seating position in motor vehicles. While safety belts are 42% effective in preventing fatalities, the addition of the driver side airbag provides a 12% increase in effectiveness. The implications of safety belt use and airbag availability over the next decade are considered for fatal injury prevention. The analysis includes theoretical relationships and forecasts fatality prevention as lap-shoulder belt use increases and airbags phase into the vehicle fleet.

Evaluating Low-Speed Rear-End Impact Severity and Resultant Occupant Stress Parameters

Automotive Systems Analysis, Inc. (ASA) and Lowell Hicks, Inc. (LHI) have developed a ground-up set of sensor instrumentation and recording method to document vehicle-artifact/occupant-stress parameters occurring from a continuing series of low-speed rear-end multi-vehicle impact tests (approximately 2 to 8 MPH). This work has four goal areas: 1) calculate impacted vehicle (TARGET) barrier equivalent velocity (BEV) from isolator Artifacts; 2) correlate calculated BEV' to occupant stress; 3) calibrate injury potential of occupant stress impulse; 4) compare occupant stress with everyday volunteer activities. The test collision series now includes several different vehicle pairs with varying impact/escape speeds, weight ratios, and parallel parameters from a driver side manikin and passenger side volunteer. Observable physical vehicle isolator artifacts (piston stroke scrapes) were compared with computer-recorded linear sensor time traces, and these data were fitted to a 'calculated BEV' worksheet/algorithm. The worksheet/algorithm method shown here was found to be reasonably repeatable, per vehicle model and series tested. Next, manikin and volunteer occupant stress data, measured along with TARGET vehicle BEVs, were charted and compared with injury-threshold-impulse criteria referenced in the literature. Lastly, the occupant-stress impulses were compared with sample stress impulses for various volunteer physical activities, as a practical calibration of vehicle occupant stress.

Automotive airbag-induced second-degree chemical burn resulting in Staphylococcus aureus infection

A young woman did not seek emergency treatment after a minor automobile collision as she thought that she had been spared serious injury by the inflation of the driver's-side airbag. She had a benign-looking erythema on her neck which, over the next several days, became a second-degree chemical burn infected with Staphylococcus aureus. The burn and subsequent infection took several weeks to heal and the patient had to endure a prolonged course of antibiotics, nonsteroidal antiinflammatory drugs, and continued irrigation. This case exemplifies why alkali chemical burns from an automotive airbag should be treated aggressively, despite their benign appearance, as they may take several days to evolve. Physicians should be warned that careful follow-up examination of patients seen in the hospital emergency department or in the physician's office is necessary to abate any hidden sequelae. Of course, the opportunity to decrease morbidity is lost if the patient does not seek emergency treatment.

PATTERNS OF FRACTURE AFTER AIR BAG DEPLOYMENT

The airbag restraint system has been described as a means of reducing fatalities in frontal crashes. This conclusion is based on crash investigations and statistical extrapolation, but few data exist to document specific fracture patterns and injuries after airbag deployment. Seven cases of driver's side airbag deployment after motor vehicle crashes were studied for extent of injury. Unrestrained (non-seatbelted) drivers demonstrated flexion injuries of the cervical and thoracic spine and direct impaction fractures of the face and sternum. One restrained (lap-shoulder belt) driver demonstrated an extension injury of the upper cervical spine. What may emerge from further study is a decrease in fatalities, but also a pattern of fractures specific to airbag use.

Corneal Edema, Hyphema, and Angle Recession After Air Bag Inflation

Several recent reports have documented severe ocular trauma after air-bag inflation during motor vehicle accidents.1,2Scott et al2reported a case in which a patient sustained periorbital fractures, retinal tears, and lens subluxation during a single vehicle accident in which the driver's-side air bag inflated. We describe herein a patient who developed localized corneal edema, hyphema, and angle recession following trauma after air bag inflation during a motor vehicle accident. Report of a Case. A 51-year-old man, wearing a three-point lap-shoulder seat belt and driving a late-model Mazda RX7 was involved in a two-car frontal collision in which both vehicles' driver's-side air bags inflated. The approximate speed of the vehicles was 15 to 20 mph. The other driver, who was also restrained with a three-point lap-shoulder seat belt, was unhurt. The make and model of her vehicle were not known. Our patient sustained abrasions to the right side

Retinal Detachment Caused by Air Bag Injury

A 40-year-old man drove his automobile into a road-side ditch to avoid an oncoming car. He struck a tree stump at a speed of 10 to 15 miles per hour, causing inflation of the driver's-side air bag, which struck his face and upper body. He did not strike any other components of the car's interior. He was wearing a three-point lap-shoulder belt and was not wearing glasses. Immediately after the accident, the patient noted visual loss in the right eye. A vitreous hemorrhage was noted by his ophthalmologist. One month later he was noted to have developed a retinal detachment in the right eye. His visual acuity was hand motions in the right eye and 20/15 OS. Examination results of the left eye were normal. In the right eye, intraocular pressure was 41 mm Hg and inferior angle recession was present. There were 2+ cells and 3+ flare in the

Air Bag: Friend or Foe?

As Moreand more cars are equipped with air bags, the number of reports of air bag—related eye injuries is also growing. 1-8 When a new product, originally introduced to enhance safety, is itself identified as the possible source of trauma, it is time to reevaluate the product's usefulness. Our search of the international literature found eight publications reporting on air bag—related eye injuries. Others appear in this issue of theArchives. 9-13 An analysis of the details of the ocular trauma, the outcome, and the circumstances of the motor vehicle crash (MVC), as found in these previously published reports, is as follows. See also pages 1317, 1318 and 1320 The title of the first report 1 left no doubt as to the cause of the injury: Severe Ocular Trauma From a Driver's Side Air Bag. However, if one reads the Comment section of this case report, serious doubts