My journey with CMS began over a decade ago as my first commercial research project. I was truly fascinated with the tech and its potential benefits. Throughout the years, I have conducted dozens of experiments for both passenger and commercial vehicles.
I believe there is a substantial difference in the application of this technology between passenger cars and commercial vehicles. For commercial vehicles, particularly large trucks, the benefits of CMS are undeniable. The improved visibility, reduced blind spots, and enhanced safety features make a compelling case for their adoption. In these vehicles, the advantages far outweigh the challenges, hence the adoption by companies like Volvo, MAN, and Mercedes.
However, there are several challenges:
Managing screen brightness to match ambient light is crucial, ranging from high brightness during daytime to extremely low brightness at night. Additionally, the positioning of the displays should promote horizontal visual scanning while minimising sun reflections and reflections from the screen to the windows at night.
For effective distance estimation, the use of reference lines overlays is important. Honda Research has been a pioneer in their research into the usability verification of distance reference lines. These reference lines help drivers accurately evaluate the distance to other objects and vehicles.
CMS displays a flat digital feed that lacks the natural depth cues provided by traditional mirrors, which can complicate distance judgement and identification of details. This is particularly challenging for older drivers who may struggle with visual accommodation due to presbyopia. While magnification techniques can help, they require larger displays, posing additional design challenges. I believe that visual accommodation issues make the CMS application in passenger cars less promising.
Despite the design flexibility that CMS provides for the exterior, it takes its toll on interior design. Integrating displays within the instrument panel can be challenging, particularly in passenger cars. A good-sized display for a car is around 7 inches, which causes several packaging constraints and will undoubtedly meet resistance from interior designers.
The experimental protocols to test CMS are highly complex, but they help gather invaluable user feedback. Initial impressions and system acceptance are usually low, and driver adaptation can take significant time. I can still recall my initial excitement but also the disorientation and confusion I experienced during my first public road drive in the Audi e-tron.
CMS is a clear yes for large vehicles due to their significant benefits in visibility and safety. However, for passenger cars, the challenges and integration issues make them a no for now. Nonetheless, the Honda e boasts the best e-mirror system I have experienced in passenger cars, so it can be done!