The U.S. Government Needs Your Help To Decide If Cameras Should Be Allowed To Replace Mirrors

Image: Hussein Malla/AP

The U.S. government is seeking input from the public so it can decide if cameras should be allowed to replace mirrors in our cars, like they are in other countries. Specifically, Bloomberg notes, the feds want research, because they’ve got a number of concerns about this whole camera-instead-of-mirror concept.

Federal Motor Vehicle Safety Standard No. 111 requires that automakers outfit cars with an inside rearview mirror and at least the driver’s side outside mirror, plus the standard sets certain field-of-view and mounting requirements. The idea, NHTSA says, is to try to “[reduce] the number of deaths and injuries that occur when the driver of a motor vehicle does not have a clear and reasonably unobstructed view to the rear.”


Now, after receiving two petitions from “industry stakeholders,” NHTSA is considering amending the standard to allow camera-based rear visibility systems—also called Camera Monitor Systems—to comply with the law and act as mirror-alternatives.

These systems generally incorporate onto A-pillars rear-facing cameras, whose pictures are displayed onto monitors somewhere in the vehicle, sometimes mounted in the door like in this Audi E-tron that my coworker Mack took a picture of at the Frankfurt Motor Show this year:

Image Taken By: Mack Hogan

The two aforementioned petitions, NHTSA says in its recently published “Advance Notice of Proposed Rulemaking,” which seeks comments from the public, come from two sources: one from Tesla and the Alliance of Automobile Manufacturers, and the other from Daimler Trucks North America.

The latter discusses commercial vehicles and the former talks about light-duty cars and trucks, but both are pushing for Camera Monitor Systems because of their potential fuel economy benefits thanks to improved aerodynamics. Better field-of-view is also cited as a driving force behind the push towards digital mirror-replacements.


What NHTSA is specifically interested in when it asks for public comment to inform the agency’s next steps on this issue is data-based research on the safety of Camera Monitor Systems, specifically in comparison to the current FMVSS No. 111 mirror requirements.

NHTSA describes two safety concerns that it wants addressed, one dealing with a concept called “blooming,” which is image distortion resulting from a bright light source like headlights. From the notice:

Research conducted by NHTSA and others conducted between 2006 and 2017 has consistently shown that prototype and preproduction CMS systems can exhibit safety-relevant performance issues such as blooming. Moreover, the CMS-related research of which NHTSA is aware does not focus on human factors issues, such as how well drivers may be able to acclimate to the use of CMS and potentially different image locations.


But NHTSA isn’t just asking the public for all the answers to its homework. The agency cites a number of other studies on the technology including its own research comparing a prototype camera system in a 2016 Audi A4 with a conventional mirror setup in a 2017 model—research that yielded the following concerns:

 The image appeared to be horizontally compressed, such that objects displayed on the CMS screen were narrower and thus more difficult to detect.

 The CMS display was mounted lower than traditional mirrors, which may be temporarily disorienting for drivers. (It should be noted, however, that despite initial disorientation, drivers were able to acclimate to the CMS.)

 The display appeared very bright in certain conditions, even when set to “nighttime” mode, which may negatively impact the driver’s ability to see obstacles at night.

 The system appeared to have blooming and lens flare that exceeded the level permitted under the new ISO standard for CMS under certain conditions.

 In rainy conditions, droplets on the lens would obscure the image displayed to the driver.


In its notice, NHTSA lists over 20 subjects on which it would like to receive from the public “research, evidence, and/or objective data.” Those subjects are broken down into a number of areas, with the first being “Existing Industry Standards”:

1) Please provide research data concerning the safety impacts of replacing rearview mirrors with CMS. Please explain your view of the significance of those data. In addition, please explain your views on how CMS-equipped vehicles would impact light and heavy vehicle driver behavior and situational awareness while driving.

2) Are the physical properties of mirrors necessary to meet the stated purpose of FMVSS No. 111 to provide a “clear and reasonably unobstructed view?” As an example, because each eye of a driver viewing objects reflected in a mirror has a slightly different angle of view of those objects, just as the eyes of a driver viewing those objects directly would have, mirrors provide depth perception similar to that provided by direct vision. As another example, mirrors offer drivers the possibility to modify their field of view rapidly by looking at the mirror from different angles. To what extent could possible CMS features which cannot be provided using mirrors (e.g., zoom, night vision) offset the loss of these mirror-specific properties?

3) We seek comment on the performance of current world-market vehicles equipped with CMS when evaluated according to the ISO 16505/UNECE R46 standards. In particular, we seek comment on the performance requirements in these standards, and the on-road performance of CMS that meet these standards. Please identify any performance requirements for CMS that you believe are not stringent enough, are too stringent, or are unnecessary, and explain the basis for your beliefs. Please identify any requirements that you believe should be added and explain the basis for your beliefs. Which CMS have performed relatively well, and which have performed relatively poorly, on the road? What explains the difference in performance?


The second category is “System Field of View and Related Test Procedures”:

4) We seek comment on whether and, if so, why minimum field of view requirements for CMS should differ from the current minimum field of view requirements for mirrors under FMVSS No. 111. Petitioners have stated that providing drivers with expanded views, larger than those required by FMVSS No. 111, would be advantageous. What data exist to support this assertion? What, if any, potential advantages and disadvantages, such as increased eye glance durations, may be observed for wide-view images? Please provide research or data that addresses how wider views will affect image quality.

5) We seek comment on whether NHTSA should permit CMSs that use multiple cameras to provide multiple fields of view to the driver in the same image display area. In particular, we seek comment on the safety benefits/disbenefits of permitting multiple fields of view. As an example, CMS that operate using multiple fields of view might have missing sections on the processed image, or image latency issues stemming from increased processing time. What are the concerns, if any, regarding a multi-camera visibility system and how can they be mitigated?

6) NHTSA considered whether there might be any opportunities to combine either the cameras or the displays for the CMS with the camera or display for backup camera system that is required by FMVSS No. 111. The agency tentatively concludes that there would not be any such opportunities. Although CMS and backup camera systems would likely operate in a similar way, the systems serve different safety purposes and are used in different circumstances. Specifically, the purpose of a CMS would be to assist the driver in avoiding all crashes during normal driving, while the purpose of a backup camera is to assist the driver in avoiding backover crashes while in reverse. Perhaps more important, given the likely differences between the field of view and display image quality parameters that would apply to CMS versus backup camera systems, NHTSA believes it is unlikely that it would be technically possible to combine the two systems in such a way that they share either a camera or display monitor.40 NHTSA requests comments on this tentative conclusion.


Next, NHTSA wants to learn about “Image Quality and Related Test Procedures”:

7) We seek comment on the minimum quality of the image presented on a CMS electronic visual display to provide the same level of safety as traditional FMVSS No. 111- compliant mirrors, as well as how image quality could be objectively measured. In 40 NHTSA believes that sharing a camera would not be possible because the CMS camera would need to be aimed much higher than the backup camera, and that sharing a single display area would not be possible because both the CMS and backup camera images would need to be displayed simultaneously to provide the driver with all required fields of view when the vehicle is in reverse. particular, we seek comment on what would be the appropriate minimum camera and visual display parameters and performance metrics for a CMS (i.e., camera/display resolution, screen brightness, contrast, color, tone, and their adjustments). Should the parameters and metrics for a CMS differ from those for a backup camera system and, if so, how and to what extent? To what extent do existing CMS regulations (e.g., ISO 16505/UNECE R46) provide objective and repeatable performance requirements and test procedures to evaluate image quality? To the extent that those regulations do not provide such requirements and procedures, what changes or additions would need to be made? What new procedures, if any, would be needed to evaluate image quality appropriately and what has been done to develop such procedures?

8) We seek comment on what disruptive display aberrations (blooming, etc.) should be addressed if the agency were to develop a CMS performance standard. To what extent do existing CMS regulations (e.g., ISO 16505/UNECE R46) provide objective, and repeatable performance test procedures to evaluate display aberrations? What new procedures, if any, would be needed to evaluate display aberrations appropriately and what has been done to develop such procedures?


The next three subjects deal with “Rearview Image Display Type Related Human Factors”:

9) We seek comment on what research has been done to identify and address human factors issues like eye strain or visual fatigue from long periods of intermittent electronic visual display viewing. While we are particularly interested in research comparing driver eye strain and/or visual fatigue for users of a CMS versus users of traditional rearview mirrors, other analogous research could be useful.

10) We seek comment on research concerning differences in the ability of drivers to visually discern and focus on objects in an electronic visual display as compared to objects reflected by traditional rearview mirrors.

11) We seek comment on how a driver should be alerted that a CMS is not operating correctly, such as during a malfunction or a software update.


Here’s what NHTSA wants you to comment on related to “Side Rearview Image Display Locations, Driver Acclimation, and Related Test Procedures”:

12) We seek comment on whether and how placing the CMS displays in non-traditional locations (e.g., in the center console) would affect vehicle safety, as compared to placing the displays close to where the outside rearview mirrors would be mounted near the Apillars. In particular, we seek research concerning the impact of different image locations on the level of safety and performance among any driver demographic, and whether different image locations may lead to driver confusion.

13) We seek comment on whether research has been performed concerning the impacts of glare from sunlight and other vehicles’ headlights on the CMS display, and whether test procedures have been developed to measure glare. If performance requirements and test procedures have not yet been developed to address these problems, when and how can they be developed? What are potential strategies to mitigate glare to ensure that useful images would be provided to drivers over the greatest range of conditions possible.


Then there’s “Camera Durability, Reliability, and Related Test Procedures”:

14) We seek comment on the anticipated lifespan of the electronic visual display and camera components that would be installed in a typical CMS. Will the performance (e.g., display brightness) of components be maintained within specifications consistent with desired image quality over that lifespan, or will performance decrease due to age and/or being subject to outdoor conditions with wide temperature ranges and precipitation?

15) We seek comment on the anticipated reliability of CMS as compared to outside rearview mirrors, including any reliability data that may be available for production or prototype CMSs.

16) We seek comment on the anticipated replacement cost for a CMS that becomes inoperable due to damage or malfunction, and how that cost compares to the replacement cost of traditional powered and unpowered outside rearview mirrors.

17) We seek comment on whether and, if so, how a CMS can be weatherproofed to prevent condensation, or large water droplets, forming inside the camera enclosure, which could reduce image clarity. NHTSA has observed condensation in cameras mounted on the underside of outside rearview mirrors of recent model year production vehicles resulting in part of the camera view being unusable (e.g., the water blocks a portion of the camera’s field of view). How should adequate weatherproofing be defined? Would the durability tests in FVMSS No. 111, S14.3 for backup cameras be sufficient, and if so, why? What other test procedures exist for demonstrating adequate weatherproofing of cameras, and have those procedures been validated?

18) Depending on the mounting location, cameras may be subject to environmentally-caused lens obstructions (e.g., dirt, ice, rain drops). We seek comment on how to prevent or mitigate such lens obstructions. What performance requirements and associated test procedures simulating these conditions have been developed to evaluate whether the camera is providing a useful image?


Here’s “System Availability when Vehicle Ignition is Off”:

19) Although it is not one of the primary safety purpose of rearview mirrors, drivers often use the outside rearview mirrors after turning off the ignition and preparing to exit the vehicle to determine whether it is safe to open the vehicle door when parked alongside a traffic lane. We seek comment on whether NHTSA consider requiring that a CMS be capable of serving this function by being operational in some capacity either at all times or for a specified period of time after opening the driver’s car door. What new performance criteria would need to be developed for this purpose and what has been done to develop those criteria?


In addition, NHTSA states that it wants to understand the economic impacts of the technology, and how much consumers are interested in vehicles with camera-based rear visibility systems. It also wants to know how much the tech this is going to cost the consumer relative a standard mirror setup, and how much the reduced drag (and the resulting fuel economy benefit) would offset those additional costs.

Hopefully, enough data gets sent their way to get this “promising technology” (as NHTSA puts it) green-lit for production, especially if it really does provide a noticeable fuel economy benefit and improved visibility and styling at a reasonable cost to consumers.


You can read about how to submit your comments to the feds here in the actual notice.

Share This Story

Get our newsletter

About the author

David Tracy

Sr. Technical Editor, Jalopnik. Always interested in hearing from auto engineers—email me. Cars: Willys CJ-2A ('48), Jeep J10 ('85), Jeep Cherokee ('79, '91, '92, '00), Jeep Grand Cherokee 5spd ('94).