GM posted a story on its site detailing how its engineers went about ensuring its 2013 Cadillac ATS provides the driver with a high level of visibility by using new visibility metrics. They evaluated a number of factors, including the exterior mirror and A-pillar size, seat height, forward vision distance, side vision distance, and whether any interior features blocked the view through a window (for example headrests).
GM said its engineers were able to achieve a high internal score for forward visibility by keeping the hood low and slimming the A pillars by using high-strength steel. They also positioned the A pillars a wide distance apart, and angled them toward the driver, to give the driver a broad field of view that requires minimal head movements. They also said they designed a narrow support structure for the exterior rear-view mirrors.
Other visibility aids include an available rear-view camera, which features “dynamic guidelines” that show the vehicle’s path and available space when parking.
Preserving driver visibility is challenging with today’s vehicles due to aerodynamics, safety, and design requirements, according to the automaker. For example, GM said steeply raked windshields and A pillars required to improve aerodynamics leads to visibility challenges. Also, thicker roof pillars needed to accommodate air bags, and higher deck lids in the back to provide cargo room, also can mean less visibility.
To engineer these changes, GM’s Cadillac division said it used a new digital display technique (called the “hedgehog” by the company’s engineers) to examine how the A pillars affect a driver’s sightlines. The tool allows the company’s engineers to see how changes in windshield angle or section size affect sightlines, including in different driving scenarios.