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.
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 (often called rookie sticks) that fill the blanks in 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.
In short, mirrors, despite their shortcomings, have been with us since the beginning. Asking drivers to switch from the tried and true (if slightly imperfect) to a new technology with an image on a monitor recorded by a camera is going to pose its own set of challenges. But 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 system, I had driven two other trucks equipped with camera systems. But 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 an exemption from the Federal Motor Carrier Safety Administration 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.”
Getting used to monitors
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 too close to me. It was mounted on the A-pillar 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 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. Not that the image in the monitor isn’t razor sharp. It just wasn’t in the proper focal range for me. But 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 instinct. But that, too, soon became a non-issue. The monitor is front and center and there’s no missing it. Looking for the 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 OEMs use. They may save a fraction of an mpg in fuel, but visibility suffers, and that’s not a good trade-off in my opinion. MirrorEye 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 – size, perspective and all that. By closer I mean further forward toward the cab. There are three clearly visible horizontal colored lines in the monitor, a red line about halfway 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 4 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 a bit of 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 the way moving your head does with a mirror. However, 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 always in view during a turn.
Driving with MirrorEye
From the time we left Stoneridge headquarters in Novi, Michigan, I was very cognizant 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 nonexistent 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.
I was very pleasantly surprised at the night driving experience. The image in the monitor at night 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 infrared 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 of 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 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.
I had limited opportunity 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 camera monitor system. The perspective is slightly different. For example, while parallel parking the truck, I had a hard time determining how much lateral separation 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 judgment 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 to readjust to. Again, it’s not any fault with the system 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. But 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.
As I noted at the beginning, I was skeptical going into this test drive. My initial feelings were that “they” were taking something known and familiar away from 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.
But Stoneridge has done an admirable job of replicating the mirror experience and actually improving it in some ways – especially with the infrared 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, FMCSA and others 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. As an 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.