Trading truck mirrors for monitors: A test drive

Jim Park
Stoneridge mirrors
In infra-red view for night driving, colors are unnatural, but the clarity and detail of the image is greatly enhanced, especially on dark roads where lighting isn’t present.

TORONTO, Ont. — For the record, I have previously expressed a high degree of skepticism about replacing traditional mirrors with camera and monitor systems. Glass mirrors work well enough and drivers are very familiar with them. I can’t think of another safety system on a truck that drivers rely upon more heavily and have grown more accustomed to than mirrors.

That said, mirrors do leave areas of less-than-ideal visibility, but drivers compensate by looking twice at those so-called blind spots. Many trucks are fitted with fender-mounted mirrors — so-called “rookie-sticks” — which fill in the blanks quite nicely and are valued even by some veteran drivers.

I have heard many new tractor-trailer drivers say getting used to their mirrors was nearly as challenging as learning to shift a non-synchronized transmission. It does take time to mentally compensate for the lack of depth in a mirror, and to learn where the end of the trailer is relative to a certain point in the image reflected in the mirror.

In tight-turn maneuvers, the rear of the trailer can completely disappear from view, forcing the driver to adjust the field of view by leaning forward while turning. The smaller convex mirrors help in this regard, but the image reflected by the “fish-eye” convex is distorted and the distance between objects is greatly compressed. Still, drivers learn to compensate for this and usually safely navigate most tight situations.

All that to say, mirrors, despite their shortcomings, have been with us since the beginning, and asking drivers to switch to a new technology is going to pose its own set of challenges. If my recent experience with the MirrorEye Camera Monitor System from Stoneridge is any indication, the learning and acceptance curves will not be as steep as some may think.

Prior to test driving the MirrorEye camera monitor system, I had driven two trucks equipped with CMS. Those trucks also had conventional mirrors, so I ignored the new technology, except to glance at the monitor occasionally to verify or compare what I was seeing in the monitor to what I saw in the mirror. Since Stoneridge is presently the only supplier with a U.S. FMCSA exemption allowing it to operate trucks without conventional external glass mirrors, ignoring the A-pillar-mounted monitors wasn’t an option on this test drive. They were all I had.

I had the benefit of a pre-drive briefing with Stephen Fox, Stoneridge’s vice-president of business development, and Ray Kirkland, a research engineer and veteran driver who has been instrumental in developing the MirrorEye system. So I knew what to expect when I hit the road. I also learned that Stoneridge currently has MirrorEye systems installed at 14 fleets with an estimated 5 million miles of evaluation testing — and zero reported accidents stemming from the use of the system.

“Drivers respond to MirrorEye the same way they do with automated manual transmissions,” Kirkland told me. “It takes a bit of coaxing to get the veterans to try it, but none of them want to go back to conventional mirrors after they try it.”

Three colored lines embedded in the image seen in the monitor show the rear of a 53-foot trailer (red), a position 40 feet behind the trailer (yellow) and 80 feet behind the trailer (green). Note: this image is a screen grab from video shot by a GoPro camera, not a screen grab from the actual monitor.

Driving with MirrorEye

My 40 years of driving experience turned out not to be as a large a handicap as I had feared. I think most drivers will see themselves in my initial observations.

When I first sat in the driver’s seat, the left-hand monitor seemed way to close to me. It was mounted on the A-pillar after all, less than an arm’s-length from my face. As an aside, I wear bifocal glasses, with the lower part of the lens tuned for reading, which is usually done at about the same distance away from my face as the monitor. Consequently, I sometimes found myself looking through the lower portion of my glasses for a clearer image in the monitor. It’s not that the image in the monitor isn’t razor sharp. It is. But it wasn’t in the proper focal range for me. My mind’s eye papered over that problem soon enough and I hardly noticed it after a few minutes.

The next incongruity was looking out the window to where the mirror used to be. It’s instinctual, but that too soon became a non-issue. The monitor is front and center and there’s no missing it. Looking for the outside mirror was muscle memory more than anything else.

These two “issues” weren’t a factor for the right-hand monitor. It’s far enough away for clear focus through the top of my glasses and it’s close enough to where a mirror should be that my gaze hit the target every time. The advantage of the monitor’s position on the A-pillar is the elimination of the lateral blind spot caused by the ridiculously large aero-mirror cowlings all the OEM’s use. They may save a fraction of a mile-per-gallon, but visibility suffers and that’s not a good trade-off in my opinion. MirrorEye’s CMS solves that problem.

The view through the monitor is different from that of a mirror — not drastically, but noticeably. Again, there was this thing in the back of my mind that I expected to see, but it wasn’t what I saw. For example, the objects in the right-hand monitor appeared larger than they would in a mirror. Not a bad thing, but my initial thought was that objects beside me appeared closer because of size, perspective and all that. By closer I mean further forward toward the cab. MirrorEye alleviates that discrepancy with three clearly visible horizontal colored lines in the monitor — a red line about half-way up the screen, a yellow line slightly above the red line, and a green line just above the yellow one. The red line represents the rear of a 53-foot trailer, plus four feet. The yellow line is 40 feet behind that, and the green line represents 80 feet behind the trailer.

The lines were Kirkland’s brainchild and instantly remove any doubt the driver may have about where traffic is relative to the rear end of the wagon. Because my familiar reference points in a mirror no longer applied, these colored lines made up the difference.

The other thing that took getting used to is the field of view. It’s wider in the monitor than a traditional mirror, so you see more of what’s around you. That’s good. The awkward part was getting used to the fact that leaning forward or getting in closer to the monitor has no impact on what you see. Moving your head does with a mirror — considering angles of reflection and all that. That said, the driver can pan the field of view with a rotary control on the dash. And the field of view follows the trailer in a turn. MirrorEye has cleverly designed a tracking feature into the camera/monitor algorithms that pans the view to follow the back of the trailer. The trailer wheels are almost always in view during a turn.

Stoneridge control
A control module allows drivers to pan the field of view slightly left or right, retract the camera wings, and adjust the brightness of image in the monitor to suit their taste.

From the time we left Stoneridge headquarters in Novi, Mich., I was very aware of what was going on around me, more so than usual. I was aware of the different fields of view and the different perspective offered by the monitors, so I was trying to calibrate this new view of the world with my historic expectations. It took less than 30 minutes until I stopped looking out the window for the non-existent mirror. It took a little longer until I was comfortable with a passing maneuver.

I recall passing one of those slow-moving Michigan centipedes, looking into the monitor at about the time I felt it would be safe to pull back into that lane and thinking, “I’m not really seeing this, it’s just a visual representation of what’s happening beside me.” In a mirror, you get visual confirmation — eyes to brain. While the camera-monitor-eyes-brain connection is no different, it did take a few moments before I was totally comfortable trusting what the monitors showed me. I was fine from then on.

I even managed to navigate a double-roundabout on Michigan 23, just south of I-96. I came upon it unexpectedly and it rattled me a little, but the CMS got me through just the way a well-focused pair of mirrors would have.

Stoneridge mirrors
In infra-red view for night driving, colors are unnatural, but the clarity and detail of the image is greatly enhanced, especially on dark roads where lighting isn’t present.

Night Driving: The Acid Test

I was very pleasantly surprised at the night driving experience. The image in the monitor is not optical but infrared. The night image was fantastically clear and super well defined. I could even see the tar snakes and skid marks on the pavement surface when it was pitch black outside because IR doesn’t require light. The white lines were as bright as day, and best of all, there was absolutely no headlight glare from overtaking cars. The headlights appear as white circles or squares on the front of the car. That’s it. No glare at all.

Stoneridge has a done a very good job calibrating the brightness of the monitors. During the day, the image was as bright as my surroundings, and the same at night. It wasn’t too bright and distracting, nor too dim and difficult to resolve. In fact, the daytime image was as good as I’d expect from a mirror, and the night image much better than a traditional mirror.

Sunlight shining into the camera from behind produced a slight blooming effect, but the electronics subdued about 90% of it. The image in the monitor remained as clear as before, with a slight white glow where the ball of the sun was accompanied by red and green colored streaks. At one point, with the sun low in the sky and at my side, the glare on the monitor screen did wash out the image to some extent, the way a laptop screen gets washed out when it’s outside. This was really the only issue I experienced with the system.

Read more about the MirrorEye

I had few opportunities for backing maneuvers, but I can tell you it takes a bit of adjustment. Again, I think it’s more a matter of historic expectation rather than problems with the CMS. The perspective is slightly different. For example, while parallel parking the truck, I had a hard time determining how much lateral space existed between the left side of the trailer and a set of orange cones set up to represent a parking space. Because I could not confidently determine how much space I had on the left (where I could see clearly), my judgement on how much room I had on the right (where I could not see because of the articulation of the truck) was compromised. In real life, I would have just bailed out for a look.

Both Fox, onboard for the drive, and Kirkland, standing in the parking lot watching, agreed that backing is something you have readjust to. I’ll stress, it’s not any fault with the CMS generally, but using monitors rather than mirrors where precision maneuvering is necessary required a bit of mental recalibration.

There’s another monitor I haven’t mentioned yet, Stoneridge calls it the look-down monitor. Its camera is focused on the right-hand side of the tractor and it covers an area from the drive wheels to the front bumper. In this truck, the monitor was placed at the top center of the windshield. There’s no formal reason for putting it there except Kirkland says that’s where other drivers have told him they want it. To me, it was an unnatural place to look for objects sitting to the right of the truck. And during my driving career, I never did use those door-mounted look-down mirrors that sit above the passenger window. The look-down camera was certainly effective at providing a clear view of a traditional blind spot, but I have developed different ways of coping with that blind spot over the years.

I found the difference between mirrors and the monitors similar to what I experienced when I switched from a Nikon single-lens reflex camera with an optical view finder to a Fuji mirrorless camera with its digital viewfinder display. It was no better or worse, just different.

The monitors are clear and bright, but not overly so, and the field of view is wider. Objects in the right-hand monitor appeared larger than I had been accustomed to with mirrors, but that’s helpful. If nothing else, your muscle memory will trigger you to think it’s closer than it actually is, thus adding a level of caution.

As I noted at the beginning, I was skeptical going into this test drive. My initial feelings were that “they” were taking away something known and familiar to drivers, and replacing it with some engineer’s idea of a better way — all in the interest of saving a couple of points in fuel economy.

Since MirrorEye is the first, and so far, the only CMS provider to gain an exemption from maintaining glass mirrors as a redundancy, any previous driving experience I had with monitors doesn’t really count. Stoneridge has done an admirable job of replicating the mirror experience and actually improving it in some ways. Especially with the IR night driving setup.

What remains to be seen is how the standards and legal requirements for such systems will evolve. The National Highway Traffic Safety Administration, the Federal Highway Administration, Federal Motor Carrier Safety Administration, and Transport Canada will be tasked with defining how such systems should perform and other manufacturers will need to comply with those standards.

Stoneridge has set the bar pretty high. And as a very experienced driver, I’m going to jump on board and say this is a go for me. I think new drivers, those who haven’t yet acquired the mirror muscle memory, will have an even easier time adjusting.



Jim Park

Jim Park was a CDL driver and owner-operator from 1978 until 1998, when he began his second career as a trucking journalist. During that career transition, he hosted an overnight radio show on a Hamilton, Ontario radio station and later went on to anchor the trucking news in SiriusXM's Road Dog Trucking channel. Jim is a regular contributor to Today's Trucking and, and produces Focus On and On the Spot test drive videos.

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