Japanese and European regulations permit CMS (camera monitoring systems) rather than traditional side- and rearview mirrors. US regulations don’t, but perhaps that will eventually change: Tesla and the Alliance of Automobile Manufacturers petitioned NHTSA five years ago, and Daimler Trucks North America put in a petition of their own a year later in 2015, to allow cameras instead of mirrors, citing improved fuel economy through reduced aerodynamic drag. Now NHTSA have issued a request for public comment and data in response to a comprehensive set of questions about the technology.
Camera monitoring systems are said to offer 35° view fields, compared with the 17° of conventional door mounted mirrors—though the latter figure depends on whether local regulations require plain flat driver-side mirrors with “unit magnification”, as in US Federal Motor Vehicle Safety Standard № 111, or allow convex and aspherical ones as in UN and Japanese regulations. A wider field of view helps to reduce blind spots. The images from the camera being displayed on in-car monitors can bring another safety benefit, because drivers needn’t move their eyes as far from the normal road gaze to see the side view, but only if the display is thoughtfully positioned and configured. If not, it can lead to the likes of this unfavourable review on a popular auto enthusiast website.
And it’s not just enthusiasts who have objections to some of the systems that have been commercialised; NHTSA say camera monitoring systems may also introduce new safety risks. A five-year agency study of CMS on heavy-duty vehicles found display screens were too bright, causing distraction and glare for drivers. And the agency’s tests two years ago of a prototype passenger car CMS found better-quality images than mirrors at dusk and dawn, but also displays that were too bright at night, distorted images and “bloom” from headlights in the image, and cameras easily obscured by raindrops.
Comments are due by 10 December.
