Vision

Last Edited: January 26, 2020 // by TruckerScape, Inc.

Basics

The key vision advantage I have in my truck is a higher observation point than you have in your car or pickup truck.  I can look well ahead over the tops of personal vehicle traffic, spot possible trouble and slow down or stop if necessary.  I’m always working to maintain a safe following distance to be able to take evasive action.  Trucks block my view ahead, but their drivers are able to take similar precautions and I stay alert to their actions.

Seeing You in the Lanes Next to Mine

Because my OTR (“over the road”) tractor is equipped with a double bunk sleeper and tows a tall box trailer, a rear window would serve no purpose.  I have to use side mirrors to see what is behind me and also much of what is beside me.  To see traffic behind me in the lane next to mine on either side I primarily use two large rectangular flat mirrors, one mounted on each tractor door.  These are aimed so I can look along the sides of my trailer and on to the horizon behind me.  The trailer tandems are still fully visible above the mirrors’ bottom rims, to help me align the trailer inside dock and parking lane lines.  You do not show up when driving close behind my trailer; hence the cautionary message on some trucks’ trailers “If you can’t see my mirrors I can’t see you.”

In the large left flat mirror I can see your vehicle alongside my trailer until you’ve reached the midships (middle) section (advanced past the trailer’s midships turn signal/emergency flasher light).  Forward of that point I have to pick you up in two small rectangular mirrors on the left side of my tractor.  One of these is mounted below the large mirror and the other toward the front of the tractor over its left fender.  In the right lane next to mine your vehicle’s image leaves the large right flat mirror sooner, when you’ve passed the rear section of my trailer alongside the tandems.  Forward of that position I have to use the corresponding two small mirrors on the right side of my tractor.

(The fender mirrors used to be mounted or braced on the fenders themselves.  This was common before the fenders became molded with the hoods as a single component.  Now on most later model tractors the supports are attached to the sides of the hood and angled outward to position the mirrors over the fenders.  We will still refer to them as fender mirrors.)

While the large mirrors are flat, the small ones are convex—“fish eyes.”  As with other convex mirrors, these mirrors make vehicles appear to be smaller and farther back than they actually are.  Vehicles approaching my truck from the rear horizon in the lane next to mine on the left appear in the convex mirror below the large left flat mirror only as specks at first, their images growing until they leave just before the vehicles get alongside my tractor’s left door.  Conversely, vehicles approaching my truck from the rear horizon in the lane next to mine on my right appear in the convex mirror below the large right flat mirror only as specks at first, their images growing until they leave just before the vehicles get alongside my tractor’s right door.

The fender mirrors enable me to see low along the sides of the tractor and trailer.  Vehicles in the left lane next to mine show up in my left fender mirror starting from alongside my trailer’s tail as specks, their images growing until they leave when the vehicles get alongside my tractor’s left steer wheel.  Vehicles in the right lane next to mine show up later in my right fender mirror, when they reach the rear section of my trailer alongside the tandems.  Their images grow until they leave when the vehicles get alongside my tractor’s right steer wheel.

Growth in size and clarity of fender mirror images lag those in the convex mirrors below the large flat mirrors due to optics limitations resulting from fender mirrors’ greater distances from me.  Fender mirrors are secondary to the mirrors below the large flat mirrors for tracking a particular vehicle until the vehicle has advanced alongside my tractor.  The right fender mirror becomes very important in viewing a vehicle, particularly a low, small one as it pulls alongside my tractor on my right (“blind”) side.

In earlier model tractors I drove, the outer rims of the convex mirrors gave me a limited view of traffic two lanes over from the one I occupied.  However image sizes were reduced and somewhat distorted.  The convex mirrors didn’t capture as much light as the large flat mirrors so you showed up less well in the dark or other dimmer conditions.  In fact, in dark conditions all I could see in the convex mirrors were points of light from your headlights.  Gauging your relative position behind or alongside my truck, especially on the right side, was even more difficult.  Rain hindered vision in all the mirrors, and my tractors’ fender mirrors did not have optional heating, so snow and ice coatings could limit their effectiveness.  In my current model tractor some of these limitations have been alleviated.

Recent Vision Improvements:  Seeing You Two Lanes over from My Lane

The large flat mirrors on my newest 2017 automatic shift tractor remain essentially unchanged, still providing views two lanes over from the horizon to even with the rear section of my trailer (even with the tandems) on my left and to 60 feet behind my trailer’s tail (approximately 4 compact-size 14 1/2-foot car lengths) on my right.  (The right large flat mirror, situated farther away from me and aimed at the lane next to my lane on my right provides a much more closed, restricted view than my left large flat mirror.)

However, the improved convex mirrors give me better views of traffic two lanes over from the lane I’m in.  The fender mirrors are widened, enabling me to see vehicles advancing on my left from just behind my trailer’s tail to even with my tractor’s left steer wheel and on my right from 30 feet behind my trailer’s tail to just behind my tractor’s right door.  The right fender mirror, situated farther away from me with resulting restricted optics, provides a more limited (smaller and more distorted) view of traffic two lanes over.

The small convex mirrors below the large flat mirrors provide views two lanes over from the horizon behind my trailer to just behind my tractor’s door on my left and to my trailer’s midships (even with the turn signal/flasher light) on my right, but their images are smaller than those in the larger fender mirrors.  As in the right fender mirror, the view of traffic two lanes to the right of mine in the right convex mirror below the large flat mirror is more limited (smaller and more distorted) than the view in its left counterpart.  For other vision improvement details see the Vision–Advanced Notes tip in the Truck Handling Characteristics and Limitations chapter.  You should keep in mind that other trucks may or may not have features comparable to these.

The convex mirror images are still less clear in nighttime, bad weather or other limited visibility conditions than in daylight, and the fender mirrors are still unheated for protection from ice and snow.  And remember, many trucks do not have these newer mirrors.  As a general rule it is still safest to assume that when your vehicle is two lanes to the left or right of a truck, it is not visible to the driver until it is even with, or in front of the tractor (see the Caution Zones tips).

One other related improvement on my newest 2017 tractor is cleaner flow of water and snow off the left and right windshield panes from wipers and wind, resulting in less fouling of the surfaces of the large flat mirrors and the convex mirrors below them.

Primary Vision Limitations

(Two side points:  First, it’s important to note that my truck’s large and small mirrors are generally functional on any straight or gently curving highway or surface street.  However on sharp turns such as through intersections, my side and rear mirrored vision is limited, because the large mirror on the inside of such turns becomes aimed toward the side of my trailer and on the outside of the turns becomes aimed away from the sides of my tractor and trailer.  On the inside of such turns the small convex mirrors on that side are functional though limited with smaller, distorted images and light restrictions.  They do not provide a useful view on the outside of such turns.  On turns to my left (“sight side”), I have a fairly broad direct view out my driver’s side window.  This view is what I and other drivers employ when we perform sight side backs into parking slots or docks.  On turns to my right (“blind side”), I have a very limited direct view out my truck’s right side window.

Second, mirror configurations and shapes vary on different tractor makes and models.  For example some tractors (especially older models) do not have fender mirrors, so their drivers must rely on direct views of vehicles alongside their tractors’ fronts, and solely on their small mirrors below the large mirrors for views of vehicles alongside their tractors and for views of vehicles on inside lanes during sharp turns.  Also, drivers adjust their mirrors somewhat differently according to the make and model of their truck, their individual stature and posture, and the way they prefer to sit behind the steering wheel.  In general though, all drivers have the same vision requirements.)

Because of these mirror limitations, it is safest to stay cautious and assume you’re out of the driver’s sight when alongside a truck turning in an intersection or making any other sharp turn, especially in either an inside or outside lane during a right turn or in an outside lane during a left turn.

Since Job One for me is to mind what is in front of me and manage my truck’s direction and speed, I cannot continually scan my side mirrors.  When in cruise mode on the open highway (typically on interstates or major highways with two or more lanes in each direction, in sparse traffic, usually in rural areas) in good weather, I scan the mirrors once every five to ten seconds.  In heavy traffic or other adverse conditions I check the mirrors more frequently.  Still, it is possible for you to pull alongside me or even pass me without my having spotted you in the mirrors.  You can surprise me, especially if you are driving at a much higher speed than I.

As you probably suspect, a low rising or setting sun reflecting in my mirrors makes it difficult to see you.  Another factor is the large shadows cast by my tractor and trailer.  Even in bright sunlight, when you are in the shadows the small mirrors may not show your vehicle very plainly.  Visibility in them is dimmed further if your vehicle is painted a dark color and your vehicle does not have running lights.  At night and in other dim visibility conditions, differentiating your lights from other lights reflecting in my small mirrors takes extra effort.  Whether routinely scanning my mirrors or preparing to change lanes, I have to check more carefully in the small mirrors.  Particularly on my right (“blind”) side I will check the small mirrors several times prior to and during a lane change.

There is an important difference in vision between the mirrors on my left side and those on my right, on highways and surface streets.  Because I sit closer to the mirrors on my left side, I get broader views out the left side of my truck in those mirrors than I do in the mirrors on my right side.  The views in the right side mirrors are more constricted, and therefore you generally show up less well on my right side.

Also, sitting close to the left (“sight”) side window, I have a fairly broad angle of direct (non-mirrored) sight alongside, below and behind my tractor on the left side.  And I can catch some traffic movement on that side as it is reflected from the large mirror into my peripheral vision.

Critical Blind Spot

However, the direct sight angle out my right window is much narrower; hence the term “blind side.”  On the blind side I also have a limited direct view below the level of the side window because so much of the tractor’s interior and hood is in the way.  Once the front of your vehicle is even with the front of my tractor or slightly in front I can’t see much of you, especially at night or in other dim conditions.  Your headlights no longer show in the small mirror over my right fender and your taillights may be hidden from direct view.  Only a small part of your vehicle appears in the outer rim of the fender mirror and that fragment does not stand out in the darkened mirror reflection.

My newest tractor does have improved front and direct blind side vision, with a lowered and downward sloping dash, deeper side windows and a shortened and downward sloping hood.  The hood feature is engineered by shifting more of the rear of the engine under the dash and into the center of the cab, where it is covered by the center console.

Nevertheless, around my truck this is one of the riskiest positions for both you and me (see the Risk Zone:  Alongside the Front of My Tractor on My Right Side, Where You Do Not Show Up Well Directly out My Right Side Window or in the Convex Mirror Over My Tractor’s Right Front Fender tip).  In daylight I can see the top of your vehicle if it is a standard or large size sedan, SUV or pickup.  But if you’re driving a sports car or other low, small vehicle you virtually disappear from direct view.  I’ll know you’re there if I’ve seen you approaching and in some other instances I can just sense your presence.  In congested city traffic you may be trapped beside me, but in that case we’re usually driving more slowly and I will probably have noticed you.

But there is always the possibility that I need to change lanes to my right and have not noticed your vehicle.  In that position you are less likely to see my turn signal and warn me and/or move.  Please, let’s not chance my initiating a lane change and being startled to discover your vehicle there or tragically, hitting it.  In most circumstances, unless you are about to take an exit, it is wise to move out of that position as soon as it is practical, safe and lawful for you to do so.

Full Disclosure:  At 5 feet 8 inches tall, my lines of sight out my tractor’s right side window and across the interior and hood may be slightly more restricted than those of taller drivers.  However, I set my seat back almost perpendicular so I sit upright and slide my seat forward relatively close to the pedals and steering wheel.  Other (especially taller) drivers prefer a more reclined position with their seat back tilted rearward and the seat itself slid farther away from the pedals and steering wheel for more leg and arm room.  In that position, their lines of sight are probably not so much different from mine.

Other Vision Limitations

Another vision obstacle I deal with are the pillars (or posts) framing my truck’s front windshield.  These are thicker than those in your personal vehicle because they have to support the cab roof in an accident.  They, along with my side mirrors, block a significant swath of my direct vision to the side and front of my truck.  Especially when crossing a highway or street at an intersection that is not controlled by a traffic light or stop signs, I have to look several times in both directions to spot any approaching cross traffic (vehicle or person or animal) that has been momentarily hidden from my view.

One other blind spot is directly in front of my truck. I can look over my tractor’s hood and see an adult or large youngster in a crosswalk in front of me, but not a small child or pet.  I have to be especially watchful when stopped at an intersection or driving through a residential area.

There are special mirrors called cross over mirrors that improve truck drivers’ low front vision.  According to the New York City DOT (Department of Transportation) website, “Because of the height of large trucks, it can be difficult for truck drivers to see what is happening directly in front of their vehicles.  This has contributed to a significant number of pedestrian deaths in New York City.  Cross over mirrors must be installed on all trucks that qualify as Commercial Vehicles, are registered in New York State, and operate in New York City (except for expressways).

Cross over mirrors, installed in front of the cab of a truck, are a simple way of eliminating a truck driver’s front “blind spot” and allowing the driver to see any person at least three feet tall and passing one foot in front of the vehicle.  School buses have long been required to have cross over mirrors. The mirrors are relatively inexpensive and manufacturers typically offer them below list price, and provide bulk discounts.”¹  I wouldn’t be surprised if cross over mirrors become standard on all big rigs.

So much for my vision issues—your vision issues caused by my truck and how to deal with them will be covered in other chapters and tips.

Takeaways

Stay generally aware of how your vehicle appears in a truck driver’s direct and mirrored vision, and be especially careful if you’re driving a sports car or other low, small vehicle.

Your personal vehicle generally shows up less well on a truck driver’s right side than on the left.

When alongside a tractor on the driver’s right side, move away as soon as it is practical, safe and lawful to do so.

It is safest to assume that when your vehicle is two lanes to the left or right of a truck, it is not easily visible to the driver until it is even with, or in front of the tractor.

It is safest to stay cautious and assume you’re out of the driver’s sight when alongside a truck turning in an intersection or making any other sharp turn, especially in either an inside or outside lane during a right turn or in an outside lane during a left turn.

Citations

¹http://www.nyc.gov/html/dot/html/motorist/trucks.shtml#routes

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