New Study Indicates Rearview Mirror Is Optimal Display Location For Avoiding Accidents When Vehicles Are Reversing

That’s the primary conclusion of Exponent, a leading engineering and scientific consulting company, which recently concluded a two-month study evaluating driver interaction and performance with rearview camera systems. These systems typically consist of a rearward-mounted camera and interior display that provides a view of the area directly behind the vehicle in order to expand rearward visibility and help decrease the rearward blind zone. The displays currently are located in the interior rearview mirror or in one of several in-dash/centre console locations.



“A number of previous studies have shown that rear camera systems reduce reversing accidents and that mirror-integrated rear camera displays are more effective than those located in the centre console,” stated Douglas Young, Ph.D., who leads Exponent’s Human Factors group in Los Angeles, California, and oversaw the study along with vision experts Robert Rauschenberger PhD, and Genevieve Heckman PhD.



“Our conclusions supported these findings yet also revealed how mirror-integrated displays have additional, significant advantages,” said Young. “In short, by placing the rear camera display in the mirror, you can increase display usage, improve driver scan patterns, enhance productive gaze durations and minimise reaction times.”



The Exponent study ran more than 70 people through a series of backing manoeuvres using three 2011 Ford Edge models equipped with backup cameras. The first vehicle was equipped with an 8-inch display in the centre console, the second with a 4.3-inch display located slightly higher in the centre console, and the third with a 3.3-inch display in the rearview mirror. A sophisticated eye-tracking system monitored each driver’s eye movements during reversing tasks while a computer collected acceleration and brake-displacement data.



The study found that those driving a vehicle equipped with the mirror-integrated display had a scan pattern that closely resembled typical behaviours of drivers, spent more time utilising the display, had a higher percentage of productive glances to the display and mirrors, and reacted twice as fast in potential accident situations compared with those driving vehicles equipped with displays in the other locations.



Preventing accidents when vehicles are reversing has been a longstanding priority of the National Highway Traffic Safety Administration (NHTSA), which currently plans to finalise by 30 December 2011 new regulations requiring car makers to equip all new light vehicles sold in the USA with camera rearview systems and related displays. Currently, car makers around the globe are working diligently to ensure that all new vehicles will comply with the proposed regulations.



NHTSA’s initiatives are even affecting the automotive supply base, including Gentex Corporation, a supplier of “smart” rearview mirrors that control glare and house other electronic features, including displays. Gentex commissioned the Exponent study, primarily based on automaker requests for an evaluation of the mirror’s effectiveness as a location for displaying rear camera video.



“Most drivers agree that the mirror is the safest, most intuitive and ergonomic location for backup camera displays,” said Gentex senior vice president Mark Newton. “But we needed an objective evaluation of display performance and a better understanding of how drivers interact with rear camera displays. Based on these findings, we’re confident we can provide the automotive industry with the fastest, brightest, most effective rear camera displays available.”



”Additionally, Gentex chose Exponent to conduct this research because it is a research powerhouse that often is utilised by global car making OEMs to help resolve vehicle safety issues,” said Newton. “We felt it was important to select a company that our customers know and respect.”



Gentex believes the Exponent research has implications on future display strategies and vehicle design. As the need to display driver information in the vehicle increases, and as centre console displays become even more crowded with infotainment and other features not required for the driving task, Gentex believes its mirrors are a logical place to display additional alerts and notifications the driver needs to incorporate into the driving task.



“The mirror has always been used as a display,” said Newton. “It’s where the driver constantly looks for input needed to make driving decisions. It’s only natural, then, to deliver additional driver warning alerts via the mirror display.”



In the future, Gentex foresee mirror-borne displays that not only provide rear camera video, but also the alerts and notifications associated with advanced driver-assist systems like lane departure warning, forward collision warning and sign recognition.



Exponent is an engineering and scientific consulting firm providing solutions to complex problems. Exponent's multidisciplinary organisation of scientists, physicians, engineers and business consultants brings together more than 90 technical disciplines to address complicated issues facing industry and government today. The firm has been best known for analysing accidents and failures to determine their causes, but in recent years it has become more active in assisting clients with human health, environmental and engineering issues associated with new products to help prevent problems in the future. For more information, visit www.exponent.com.