Rear view and braking technologies

Type: Vehicles

Risk Group(s): Vulnerable Road Users

Contributing Factor(s): Vehicle Factors

Road Safety Interventions: Policy/Legislation/Regulation, Technology

Filter By: Yes

Victims of backover crashes usually involve children, persons with disabilities, the elderly, and other pedestrians. A recent Insurance Institute for Highway Safety (IIHS) study reported that 292 people are killed and 18,000 area injured each year by drivers who back into them, usually in driveways or parking lots, and that young children and senior citizens are most likely to be killed in such crashes (Insurance Institute for Highway Safety, 2014).

An analysis of data on hospitalized child pedestrian victims of motor vehicle collisions that occurred between 1994 and 2003 and which were recorded in the Canadian Hospital Injury Reporting and Prevention Program (CHIRPP) revealed that 3.4% of child pedestrian victims less than 14 years of age were involved in back-over collisions. One third of these back-over collisions (1.1% of the total number of crashes in the data base) involved a vehicle backing out of a driveway. The authors of the study (Nhan et al., 2009) indicated that almost half of back-over collisions involved children over four years of age, but that children involved in back-over collisions on driveways were significantly younger than children involved in collisions that occurred at other locations.

Gladzuri (2005) examined the effectiveness of six commercially available reverse proximity sensor systems in reducing pedestrian-vehicle crashes while reversing. He found that the effectiveness of these systems was highly dependent on vehicle speed, where a 1 km/h reduction in reversing speed resulted in up to 20% increase in accuracy. The results also showed that all systems resulted in the avoidance 95% of test collisions when vehicle speeds were between 3-4 km/h.

Mazzae et al. (2006) conducted a study of methods to reduce collisions and casualties resulting from backing passenger vehicles. The examination included eight sensor-based systems and one rearview camera only system. Two of the sensor systems included rear video as part of the system. The testing involved the measurement of a variety of aspects of object detection performance, including static field of view, static field of view repeatability, and dynamic detection range for a variety of test objects. The ability of the systems to detect adult males, 1-year old, and 3-year-old children were assessed. Response time of sensor based systems was also measured. The results of the study showed that sensor-based systems were inconsistent, unreliable, and quite limited in range for detecting child pedestrians. The authors concluded that detection ranges exhibited by the systems were insufficient to prevent many collisions with pedestrians or other objects. The rearview video systems showed pedestrians or obstacles behind the vehicle and provided a clear image of the area behind the vehicle in daylight and indoor lighted conditions.

Kidd et al. (2013) conducted a study to identify the areas behind vehicles where younger and older children (12-15, 30-36, and 60-72 month olds) are not visible and determine the extent to which vehicle technologies such as backup cameras improve visibility and parking sensors detect objects in areas that are not visible. Rear visibility in 21 2010-2013 model year vehicles equipped with a backup camera or a backup camera and rear parking sensor system was assessed in a 20 feet wide area that extended 70 feet from the bumper. A 50th percentile male observer made judgements about the visibility of targets simulating the height of the three age groups of children. Visibility judgements were made using the left and right side mirrors, rearview mirror, glances over the right shoulder through the rear window, backup camera, and parking sensors, if available. The average blind zone for a 12-15 month-old child was twice as large as the average blind zone for a 60-72 month-old child. Average sight distance from the rear bumper to a 12-15 month-old child size object was also twice as far as it was for a 60-72 month-old size object. The authors noted that, in general, the size of the vehicle was positively associated with the size of the blind zone and the sight distance from the bumper. On average, backup cameras and backup cameras combined with parking sensors reduced the blind zone for the different target heights by approximately 90%.

An evaluation carried out by the American Automobile Association of 17 vehicles with factory installed and aftermarket rear-view camera systems on a range of vehicle body styles indicated that rear visibility increased by an average of 46%. The increased visibility ranged from 36% in smaller sedans to 75% in hatchbacks. Large trucks and sport utility vehicles scored in the mid-range of vehicles evaluated. The study indicated that during inclement weather (rain, snow, or slush) the rear-view camera lens can cloud and deliver blurry images, which require motorists to resort to manual methods to confirm that the blind zone is clear (American Automobile Association, 2014).

A 2014 study on rear view cameras conducted by the Insurance Institute for Highway Safety involved 111 volunteer drivers who were asked to perform normal driving behaviours prior to backing up. As vehicles that were equipped with parking sensors, backup cameras, both or neither were backing out of a parking spot, the cutout of a stationary child appeared at the rear of the vehicle or moved into the vehicle’s path from the driver’s side. The results showed that 100% of the vehicles without cameras or sensors hit the stationary object, 94% of vehicles equipped with sensors hit the object, 56% of vehicles equipped with cameras struck it, and 75% of vehicles equipped with both cameras and sensors struck the object. The results also showed that few of the volunteer drivers hit the object if it was moving. 13% of vehicles with no technology collided with the moving object, approximately 38% with the sensors hit it, 13% with the camera struck it, and approximately 7% with the camera and sensors hit it. Overall, the proportion of drivers who struck the stationary object was approximately four times greater than the proportion that collided with the moving object.

Mehler et al. (2014) reported on research findings in experimental settings by Mazzae (Mazzzae, 2008, 2010, 2013) which found that the use of backup cameras reduced crashes in an unexpected collision trial by approximately 30% in all three studies. The authors also cited figures provided by the National Highway Traffic Safety Administration (2010), which estimated that annual fatalities and injuries occurring from backing crashes could be reduced by 46% if all vehicles were equipped with rearview video technology.

Scope of the Problem

Nhan, C., Rothman, L., Slater, M., & Howard, A. (2009). Back-over collisions in child pedestrians from the Canadian Hospitals Injury Reporting and Prevention Program. Traffic Injury Prevention, 10:4, 350-353. Retrieved from http://trid.trb.org/view.aspx?id=898582