Vision—Advanced Notes

Last Edited: January 29, 2020 // by TruckerScape, Inc.

Basics

The sections of this Advanced Vision tip contain detailed and somewhat technical and complicated descriptions of my tractor’s mirrors and views they provide.  Some description from the primary Vision Chapter is repeated to provide a foundation for your understanding.  But you don’t have to try to learn this detail.  It is presented to give you a sense for my efforts to identify, reinforce and apply the most effective ways to monitor traffic and maneuver through it.  In daylight, and especially at night and in other very dark conditions when I can see only headlights and taillights in the mirrors, the sooner I can establish the positions of vehicles around my truck the safer their drivers and I will be.

The locations in my mirrors of images of road lanes and vehicles in the lanes are key in these efforts.  These locations are nominal as they depend on my unique individual stature, seated posture behind the steering wheel and mirror aiming preferences, as well as lane variances and vehicle tracks within lanes.  Other drivers will have different image locations in their mirrors because they have different trucks, ergonomic preferences and mirror configurations.  But their vision objectives are the same as mine.

Seeing You in the Lanes Next to Mine

The Large Flat Mirrors

To see traffic behind my truck in the lane next to mine on either side, I primarily use two large, 12 inches high by 6 ½ inches wide, flat rectangular mirrors (top two corners rounded), one mounted on each tractor door.  These are aimed so I can look back along the sides of my trailer and behind it to the rear horizon.  The flat mirrors emulate in backward fashion our forward non-mirrored sight, with the road straight ahead converging to a spot or focal point in the distance and surrounding landscape and objects remaining relatively spread out in the periphery.

The Large Left Flat Mirror

On relatively straight and level stretches of highway, in the large left mirror I can see images of a strip of my lane along its left border that is not directly behind my trailer and the next lane to my left extending from slightly forward of the trailer’s midships (middle) section (forward of the turn signal/emergency flasher light) to the rear horizon at the focal point.  From my position in the driver’s seat, the focal point is close to the mirror’s inner (right) edge, bounded on the right by the image of the left side of my trailer, 5/10 up the mirror’s height (at the top of the lower right quadrant and the bottom of the upper right quadrant).

Out of an area in the mirror’s lower left quadrant bounded by the outer (left) section of the mirror’s bottom edge, the mirror’s bottom outer (left) corner and the lower section of the outer (left) edge extending from its bottom to 2/10 up the height of the mirror, images (from left to right) of the next lane to my left and the visible strip of my lane originate from a location alongside my trailer and slightly forward of the trailer’s midships.  As the lane images lead to the rear horizon in the mirror, they run upward in a left-to-right diagonal path, shrinking in size and converging to the focal point.

When You Pass Me

Vehicles gaining on my truck in the left lane next to mine from the rear horizon appear only as specks in the focal point at first.  As vehicles advance in that lane, their images expand and move from the focal point downward in a right-to-left diagonal path toward the mirror’s lower left quadrant and then exit mostly through the mirror’s outer (left) edge with small portions exiting through the lower left corner and the outer (left) section of the bottom edge, when the vehicles pass my trailer’s midships.  From the base at the bottom of the mirror’s outer (left) edge, exiting images of low profile sport cars and compacts extend from 3/10 to 4/10 up the mirror’s height while images of higher profile personal vehicles extend from 5/10 to 7/10 and images of trucks, buses and other large vehicles extend from 8/10 through the entire 10/10 of the mirror’s height.

The Large Right Flat Mirror

Similarly in the large right mirror I can see images of a strip of my lane along its right border that is not directly behind my trailer and the next lane to my right extending from the rear section of my trailer (alongside the tandems) to the rear horizon at the focal point.  From my position in the driver’s seat, the focal point is in the mirror’s upper left quadrant, 8/10 up the mirror’s height, close to the mirror’s inner (left) edge, bounded on the left by the image of the right side of my trailer.

Out of an area in the mirror’s lower right quadrant bounded by the entire length of the mirror’s bottom edge, the mirror’s bottom outer (right) corner and the lower section of the outer (right) edge extending from its bottom to 5/10 up the height of the mirror, images (from right to left) of the next lane to my right and the visible strip of my lane originate from a location alongside my trailer’s rear section.  As the lane images lead to the rear horizon in the mirror, they run upward in a right-to-left diagonal path, shrinking in size and converging to the focal point.

When You Pass Me

Vehicles gaining on my truck in the right lane next to mine from the rear horizon appear only as specks in the focal point at first.  As vehicles advance in that lane, their images expand and move from the focal point downward in a left-to-right diagonal path toward the mirror’s lower right quadrant and then exit mostly through the mirror’s outer (right) edge with small portions exiting through the bottom outer (right) corner and the outer (right) section of the bottom edge, when the vehicles pass my trailer’s rear section.  From the base at the bottom of the mirror’s outer (right) edge, exiting images of low profile sport cars and compacts extend from 6/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend from 8/10 to 9/10 and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

When I Pass You

When I pass vehicles in the left or right lane next to mine, the vehicles’ images reverse their exit path in the respective large mirror.  Images of vehicles on the left enter the large left mirror mostly through the outer (left) edge with small portions entering through the bottom outer (left) corner and outer (left) section of the bottom edge, shrinking in size and receding on an upward left-to-right diagonal path into the focal point.  On entry, images of low profile sport cars and compacts extend from the base at the bottom of the mirror’s outer (left) edge to 3/10 to 4/10 up the mirror’s height while images of higher profile personal vehicles extend from 5/10 to 7/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from 8/10 through the entire 10/10 of the mirror’s height.

Images of vehicles on the right enter the large right mirror mostly through the outer (right) edge with small portions entering through the bottom outer (right) corner and outer (right) section of the bottom edge, shrinking in size and receding on an upward right-to-left diagonal path into the focal point.  On entry, images of low profile sport cars and compacts extend from the base at the bottom of the mirror’s outer (left) edge to 6/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend from 8/10 to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

The Small Convex Mirrors

Once a vehicle in the left lane next to mine pulls forward of my trailer’s midships, I have to pick it 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 (the fender over the left steer wheel).  Similarly once a vehicle in the right lane next to mine passes my trailer’s rear section, I have to use the corresponding two small mirrors on the right side of my tractor.  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.  The mirrors’ curvature distorts and converges images of the road straight rearward and all the road’s surroundings at a sharp angle to a focal point (unlike the more natural, spread out view provided by the large flat mirrors).  Looking rearward at the road and periphery in the small convex mirrors somewhat resembles viewing them squeezed through a virtual cone from mouth to tip.

The Small Mirrors Below the Large Flat Mirrors

The convex mirrors below the large flat mirrors are the smallest (5 inches high by 6 ½ inches wide, bottom two corners rounded) on the tractor and require closer scrutiny to use.  On exit when my truck is being passed by other vehicles and on entry when my truck is passing them, even images of low profile sport cars and compacts in the left and right lanes next to my lane fill most of the outer sections of these mirrors.

The Small Mirror Below the Large Left Flat Mirror

On relatively straight and level stretches of highway, in the small convex mirror below the large left flat mirror, I can see images of a strip of my lane along its left border that is not directly behind my trailer and the next lane to my left extending from behind my tractor’s left door to the horizon at the focal point.  From my position in the driver’s seat, the focal point is in the mirror’s upper right quadrant, 7/10 up the mirror’s height, close to the mirror’s inner (right) edge, bounded on the right by the image of the left side of my tractor.

Out of an area in the mirror’s lower left quadrant bounded by the outer (left) section of the mirror’s bottom edge, the mirror’s bottom outer (left) corner and the lower section of the outer (left) edge extending from its bottom to 3/10 up the height of the mirror, images (from left to right) of the next lane to my left and the visible strip of my lane originate from a location alongside my tractor and slightly behind its left door.  As the lane images lead to the rear horizon in the mirror, they run upward in a left-to-right diagonal path, shrinking in size and converging to the focal point.

When You Pass Me

Vehicles gaining on my truck in the left lane next to mine from the rear horizon appear only as specks in the focal point at first.  As vehicles advance in that lane, their images expand and move from the focal point downward in a right-to-left diagonal path toward the mirror’s lower left quadrant and then exit mostly through the mirror’s outer (left) edge with small portions exiting through the lower left corner and the outer (left) section of the bottom edge, just before the vehicles get alongside my tractor’s left door.  From the base at the bottom of the mirror’s outer (left) edge, exiting images of low profile sport cars and compacts extend 8/10 up the mirror’s height while images of higher profile personal vehicles extend from 9/10 to 10/10 up the mirror’s height and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

The Small Mirror Below the Large Right Flat Mirror

Similarly in the small convex mirror below the large right mirror, I can see images of a strip of my lane along its right border that is not directly behind my trailer and the next lane to my right extending from behind my tractor’s right door to the rear horizon at the focal point.  From my position in the driver’s seat, the focal point is in the mirror’s upper left quadrant, 7/10 up its height, close to the mirror’s inner (left) edge, bounded on the left by the image of the right side of my tractor.

Out of the bottom of the mirror extending from the mirror’s bottom left corner to its bottom right corner, images (from right to left) of the next lane to my right and the visible strip of my lane originate from a location alongside my tractor and slightly behind its right door.  As the lane images lead to the rear horizon in the mirror, they run upward in a near vertical right-to-left diagonal path, shrinking in size and converging to the focal point.

When You Pass Me

Vehicles gaining on my truck in the right lane next to mine from the rear horizon appear only as specks in the focal point at first.  As vehicles advance in that lane, their images expand and move from the focal point downward in a left-to-right diagonal path toward the mirror’s lower right quadrant and then exit mostly through the mirror’s outer (right) edge with significant portions exiting through the bottom right corner and the outer (right) section of the bottom edge, just before the vehicles get alongside my tractor’s right door.  From the base at the bottom of the mirror’s outer (right) edge, exiting images of low profile sport cars and compacts extend from 6/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend from 8/10 to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

When I Pass You

When I pass vehicles in the left or right lane next to mine, the vehicles’ images reverse their exit path in the respective small convex mirror below the large mirror.  When vehicles in the left lane next to mine have slipped back behind my tractor’s left door, their images enter the small mirror below the large left mirror mostly through the outer (left) edge with small portions entering through the lower outer corner and outer (left) section of the bottom edge.  As the vehicles slide farther back, their images shrink in size and recede on an upward left-to-right diagonal path into the focal point.  On entry, from the base at the bottom of the mirror’s outer (left) edge, images of low profile sport cars and compacts extend 8/10 up the mirror’s height while images of higher profile personal vehicles extend from 9/10 to 10/10 up the mirror’s height and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

When vehicles in the right lane next to mine have slipped back behind my tractor’s right door, their images enter the small mirror below the large right mirror mostly through the outer (right) edge with significant portions entering through the lower outer corner and outer (right) section of the bottom edge.  As the vehicles slide further back, their images shrink in size and recede on an upward right-to-left diagonal path into the focal point.  On entry, from the base at the bottom of the mirror’s outer (right) edge, images of low profile sport cars and compacts extend from 6/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend from 8/10 to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

The Small Fender Mirrors

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.  My tractor’s fender mirrors are larger (6 inches high by 8 inches wide, all four corners rounded) than the small mirrors below the large flat mirrors but their positioning and aiming limits my rearward view of the lanes next to mine.

Focal points in fender mirrors are tiny areas in the bottom of V-shaped notches formed by the images of the large mirrors’ support arms and the sides of the tractor where the arms are attached.  In daylight vehicles’ images are difficult to see when they first appear in the focal points, but headlight images are visible at night or in other dim conditions.

The Left Fender Mirror

On relatively straight and level stretches of highway, in the left fender mirror I can see images of a strip of my lane along its left border that is not directly behind my trailer and the next lane to my left extending from alongside my tractor’s left steer wheel to alongside my trailer’s tail at the focal point.  From my position in the driver’s seat, the focal point inside its reflected notch (described above) is in the mirror’s upper right quadrant, 6/10 up the mirror’s height, close to its inner (right) edge, bounded on the right by the image of the left side of my tractor.

Out of an area in the mirror’s lower left quadrant bounded by the outer (left) section of the mirror’s bottom edge, the bottom outer (left) corner and the lower section of the outer (left) edge extending from its bottom to 4/10 up the height of the mirror, images (from left to right) of the next lane to my left and the visible strip of my lane originate from a location alongside my tractor’s left steer wheel.  As the lane images lead to a location alongside my trailer’s tail in the mirror, they run upward in a left-to-right diagonal path, shrinking in size and converging to the focal point inside its reflected notch.

When You Pass Me

Vehicles gaining on my truck in the left lane next to mine from the rear do not appear in the left fender mirror until they get alongside my trailer’s tail, where they first appear only as specks in the focal point inside its reflected notch.  As vehicles advance from that location, their images expand and move from the focal point downward in a right-to-left diagonal path toward the mirror’s lower left quadrant.  The images exit the mirror through its outer (left) edge when the vehicles get alongside my tractor’s left steer wheel.  From a base at the mirror’s outer (left) edge that is 1/10 up the height of the mirror, exiting images of low profile sport cars and compacts extend to 6/10 up the mirror’s height while images of higher profile personal vehicles extend from 7/10 to 8/10 and images of trucks, buses and other large vehicles extend from 9/10 through the entire 10/10 of the mirror’s height.

 The Right Fender Mirror

Similarly on relatively straight and level stretches of highway, in the right fender mirror I can see images of a strip of my lane along its right border that is not directly behind my trailer and the next lane to my right extending from alongside my tractor’s right steer wheel to the rear section of my trailer alongside the tandems.  From my position in the driver’s seat, the focal point inside its reflected notch (described above) is in the mirror’s upper left quadrant, 6/10 up the mirror’s height, close to its inner (left) edge, bounded on the left by the image of the right side of my tractor.

Out of an area in the mirror’s lower right quadrant bounded by the outer (right) section of the mirror’s bottom edge, the bottom outer (right) corner and the lower section of the outer (right) edge extending from the edge’s bottom to 3/10 up the height of the mirror, images (from right to left) of the next lane to my right and the visible strip of my lane originate from a location alongside my tractor’s right steer wheel.  As the lane images lead to a location alongside the rear section of my trailer in the mirror, they run upward in a right-to-left diagonal path, shrinking in size and converging to the focal point inside its reflected notch.

When You Pass Me

Vehicles gaining on my truck in the right lane next to mine from the rear do not appear in the right fender mirror until they get alongside the rear section of my trailer, where they first appear only as specks in the focal point inside its reflected notch.  As vehicles advance from that location, their images expand and move from the focal point downward in a left-to-right diagonal path toward the mirror’s lower right quadrant.  The images exit mostly through the mirror’s outer (right) edge with significant portions exiting through the bottom outer (right) corner and the outer (right) section of the bottom edge, when the vehicles get alongside my tractor’s right steer wheel.  From a base at the bottom of the mirror’s outer (right) edge (0/10 up the height of the mirror), exiting images of low profile sport cars and compacts extend from 5/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend from 8/10 to 9/10 and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

When I Pass You

When I pass vehicles in the left or right lane next to mine, the vehicles’ images reverse their exit path in the respective fender mirror.  When vehicles in the left lane slide back alongside my tractor’s left steer wheel, their images enter the left fender mirror through its outer (left) edge and bottom outer (left) corner.  Then as the vehicles slide farther back to a location alongside my trailer’s tail, their images shrink in size and recede on an upward left-to-right diagonal path into the focal point inside its reflected notch in the upper right quadrant.  From a base at the mirror’s outer (left) edge that is 1/10 up the height of the mirror, entering images of low profile sport cars and compacts extend to 6/10 up the mirror’s height while images of higher profile personal vehicles extend from 7/10 to 8/10 and images of trucks, buses and other large vehicles extend from 9/10 through the entire 10/10 of the mirror’s height.

When vehicles in the right lane slide back alongside my tractor’s right steer wheel, their images enter the right fender mirror mostly through the mirror’s outer (right) edge with small portions entering through the bottom outer (right) corner and the outer (right) section of the bottom edge.  Then as the vehicles slide farther back to a location alongside my trailer’s rear section, their images shrink in size and recede on an upward right-to-left diagonal path into the focal point inside its reflected notch in the upper left quadrant.  From a base at the bottom of the mirror’s outer (right) edge (0/10 up the height of the mirror), entering images of low profile sport cars and compacts extend from 5/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend from 8/10 to 9/10 and images of trucks, buses and other large vehicles extend through the entire 10/10 of the mirror’s height.

Seeing You Two Lanes Away My Lane

The Large Left Flat Mirror

On relatively straight and level stretches of highway, by leaning forward, in the large left mirror I can see the image of the lane two lanes to the left of my lane extending from even with the rear section of my trailer (even with the tandems) to the rear horizon at the focal point.  Recall that from my position in the driver’s seat, the focal point is close to the mirror’s inner (right) edge, bounded on the right by the image of the left side of my trailer, 5/10 up the mirror’s height (at the top of the lower right quadrant and the bottom of the upper right quadrant).

Out of an area bounded by the outer (left) edge of the mirror extending from 2/10 up the mirror’s height to 4/10 up the mirror’s height, the lane image originates from a location even with the rear section of my trailer.  As the image leads to the rear horizon in the mirror, it runs upward in a left-to-right diagonal path above and alongside the image of the first lane to the left of my lane (and thus at a shallower upward angle), shrinking in size and converging to the focal point.  Reflecting the greater distance from my truck, the lane’s image is smaller, about 4/10 the size of the image of the first lane to my left.

When You Pass Me

Vehicles gaining on my truck in the lane two lanes to the left of my lane from the rear horizon first appear only as specks in the focal point.  As vehicles advance in that lane, their images expand and move from the focal point downward in a right-to-left diagonal path toward the mirror’s lower left quadrant.  Their images travel in a path above and next to the path of images of vehicles in the first lane to my left and thus at a shallower downward angle.

When the vehicles pass the rear section of my trailer, their images exit through the mirror’s outside (left) edge from an area whose base (bottom) is 3/10 up the height of the mirror.  By the time they exit, images of vehicles two lanes to my left have grown to about 4/10 the size of vehicle images in the first lane to my left.  Images of low profile sport cars and compacts have grown to fill an area extending from the base (3/10 up the mirror’s height) to 4/10 up the mirror’s height, while images of higher profile personal vehicles have filled an area extending from the base to 5/10 up the mirror’s height and images of trucks, buses and other large vehicles have filled an area extending from the base to 7/10 of the mirror’s height.

The Large Right Flat Mirror

Similarly by leaning forward, in the large right mirror I can see the image of the lane two lanes to the right of my lane extending from 60 feet behind my trailer’s tail (approximately 4 compact-size 14 1/2-foot car lengths) to the rear horizon at the focal point.  Recall that from my position in the driver’s seat, the focal point is in the mirror’s upper left quadrant, 8/10 up the mirror’s height, close to the mirror’s inner (left) edge, bounded on the left by the image of the right side of my trailer.

Out of an area bounded by the outer (right) edge of the mirror extending from 5/10 up the mirror’s height to 6/10 up the mirror’s height, the lane image originates from a location 60 feet behind my trailer’s tail (approximately 4 compact-size 14 1/2-foot car lengths).  As the image leads to the rear horizon in the mirror, it runs upward in a right-to-left diagonal path above and alongside the image of the first lane to the right of my lane (and thus at a shallower upward angle), shrinking in size and converging to the focal point.  Reflecting the greater distance from my truck, the lane’s image is smaller, about 2/10 the size of the image of the first lane to my left.

When You Pass Me

Vehicles gaining on my truck in the lane two lanes to the right of my lane from the rear horizon first appear only as specks in the focal point.  As vehicles advance in that lane, their images expand and move from the focal point downward in a left-to-right diagonal path toward the mirror’s lower right quadrant.  Their images travel in a path above and next to the path of images of vehicles in the first lane to my right and thus at a shallower downward angle.

When the vehicles get 60 feet behind my trailer’s tail (approximately 4 compact-size 14 1/2-foot car lengths), their images exit through the mirror’s outside right) edge from an area whose base (bottom) is 5/10 up the mirror’s height.  By the time they exit, images of vehicles two lanes to my right have grown to about 2/10 the size of vehicle images in the first lane to my right.   Images of low profile sport cars and compacts have grown to fill an area extending from the base (5/10 up the mirror’s height) to 6/10 up the mirror’s height, while images of higher profile personal vehicles have filled an area extending from the base to 7/10 up the mirror’s height and images of trucks, buses and other large vehicles have filled an area extending from the base to 8/10 up the mirror’s height.

When I Pass You

When I pass vehicles in the lane two lanes to the left or right from my lane, the vehicles’ images reverse their exit path in the respective large mirror.  Images of vehicles two lanes to the left of mine enter the large left mirror through the mirror’s outside (left) edge from an area whose base (bottom) is 3/10 up the height of the mirror, when the vehicles have slipped back behind my trailer’s left rear section.  As the vehicles slide farther back, their images shrink in size and recede in a path above and alongside the path of images of vehicles in the first lane to my left (and thus at a shallower, almost level upward angle) into the focal point at the horizon.  The vehicle images are about 4/10 the size of vehicle images in the first lane to my left.  On entry, images of low profile sport cars and compacts fill an area along the mirror’s outer (left) edge extending from the base (3/10 up the mirror’s height) to 4/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 5/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base to 7/10 up the mirror’s height.

Images of vehicles two lanes to the right of mine enter the large right mirror through the mirror’s outside (right) edge from an area whose base (bottom) is 5/10 up the height of the mirror, when the vehicles have slipped back 60 feet behind my trailer’s tail (approximately 4 compact-size 14 1/2-foot car lengths).  As the vehicles slide farther back, their images shrink in size and recede in a path above and alongside the path of images of vehicles in the first lane to my right (and thus at a shallower, almost level upward angle) into the focal point at the horizon.  The vehicle images are about 2/10 the size of vehicle images in the first lane to my right.  On entry, images of low profile sport cars and compacts fill an area along the mirror’s outer (right) edge extending from the base (5/10 up the mirror’s height) to 6/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 7/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base to 8/10 up the mirror’s height.

The Small Mirror Below the Large Left Flat Mirror

On relatively straight and level stretches of highway, in the small convex mirror below the large left flat mirror, I can see the image of the lane two lanes to the left of my lane extending from behind my tractor’s left door to the horizon at the focal point.  Recall that from my position in the driver’s seat, the focal point is in the mirror’s upper right quadrant, 7/10 up the mirror’s height, close to the mirror’s inner (right) edge, bounded on the right by the image of the left side of my tractor.

Out of an area bounded by the outer (left) edge of the mirror extending from 3/10 up the height of the mirror to 6/10 up the height of the mirror, the lane image originates from a location even with my tractor and slightly behind its left door.  As the image leads to the rear horizon in the mirror, it runs diagonally upward in a line above and alongside the image of the first lane to the left of my lane (and thus at a shallower upward angle), shrinking in size and converging to the focal point.  Reflecting the greater distance from my truck, the lane’s image is significantly smaller, about 4/10 the size of the image of the first lane to my left.

When You Pass Me

Vehicles gaining on my truck in the lane two lanes to the left of my lane from the rear horizon first appear only as specks in the focal point.  As vehicles advance in that lane, their images expand and move from the focal point toward the top of the mirror’s lower left quadrant (5/10 up the height of the mirror).  The images travel in a path above and alongside the path of images of vehicles in the first lane to my left but at a much shallower downward angle, an almost level path.  Just before the vehicles get even with my tractor’s left door, their images exit through the mirror’s outside (left) edge from an area whose base (bottom) is 5/10 up the height of the mirror.  By the time they exit, images of vehicles two lanes to my left have grown to about 4/10 the size of vehicle images in the first lane to my left.  Images of low profile sport cars and compacts extend from the base (5/10 up the mirror’s height) to 8/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base through the entire 10/10 of the mirror’s height.

The Small Mirror Below the Large Right Flat Mirror

On relatively straight and level stretches of highway, in the small convex mirror below the large right flat mirror, I can see the image of the lane two lanes to the right of my lane extending from even with my trailer’s midships (even with the turn signal/flasher light) to the horizon at the focal point.  Recall that from my position in the driver’s seat, the focal point is in the mirror’s upper left quadrant, 7/10 up the mirror’s height, close to the mirror’s inner (left) edge, bounded on the left by the image of the right side of my tractor.

Out of an area bounded by the outer (right) edge of the mirror extending from its bottom (0/10 up the height of the mirror) to 6/10 up the height of the mirror, the lane image originates from a location even with my trailer’s midships (even with the turn signal/flasher light).  As the image leads to the rear horizon in the mirror, it runs diagonally upward in a line above and alongside the image of the first lane to the right of my lane (and thus at a shallower upward angle), shrinking in size and converging to the focal point.  Reflecting the greater distance from my truck, the lane’s image is smaller, about 5/10 the size of the image of the first lane to my right.

When You Pass Me

Vehicles gaining on my truck in the lane two lanes to the right of my lane from the rear horizon first appear only as specks in the focal point.  As vehicles advance in that lane, their images expand and move from the focal point in a downward diagonal path toward the mirror’s lower right quadrant.  The images travel in a path above and alongside the path of images of vehicles in the first lane to my right and thus at a shallower downward angle.  When the vehicles get even with my trailer’s midships (even with the turn signal/flasher light), their images exit through the mirror’s outside (right) edge from an area whose base is 3/10 up the height of the mirror.  By the time they exit, images of vehicles two lanes to my right have grown to about 5/10 the size of vehicle images in the first lane to my right.  Images of low profile sport cars and compacts extend from the base 3/10 up the mirror’s height to 7/10 to 8/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 9/10 to 10/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base through the entire 10/10 of the mirror’s height.

When I Pass You

When I pass vehicles in the lane two lanes to the left or right from my lane, the vehicles’ images reverse their exit path in the respective small convex mirror below the large mirror.  Images of vehicles two lanes to the left of mine enter the small mirror below the large left mirror through the mirror’s outside (left) edge from an area whose base (bottom) is 5/10 up the height of the mirror, when the vehicles have slipped back behind my tractor’s left door.  As the vehicles slide farther back, their images shrink in size and recede in a path above and alongside the path of images of vehicles in the first lane to my left (and thus at a shallower, almost level upward angle) into the focal point at the horizon.  Images of vehicles two lanes to my left are about 4/10 the size of vehicle images in the first lane to my left.  On entry, images of low profile sport cars and compacts fill an area along the mirror’s outer (left) edge extending from the base (5/10 up the mirror’s height) to 8/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base to 10/10 of the mirror’s height.

Images of vehicles two lanes to the right of mine enter the small mirror below the large right mirror through the mirror’s outside (right) edge from an area whose base (bottom) is 3/10 up the height of the mirror, when the vehicles have slipped back even with my trailer’s midships (even with the turn signal/flasher light).  As the vehicles slide farther back, their images shrink in size and recede in a path above and alongside the path of images of vehicles in the first lane to my right (and thus at a shallower, almost level upward angle) into the focal point at the horizon.  Images of vehicles two lanes to my right are about 5/10 the size of vehicle images in the first lane to my right  On entry, images of low profile sport cars and compacts fill an area along the mirror’s outer (right) edge extending from the base (3/10 up the mirror’s height) to 7/10 to 8/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 9/10 to 10/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base through the entire 10/10 of the mirror’s height.

The Left Fender Mirror

On relatively straight and level stretches of highway, in the left fender mirror I can see the image of the lane two lanes to the left of my lane extending from even with my tractor’s left steer wheel to just behind my trailer’s tail at the focal point.  (Leftward angling of the mirror enables me to see farther behind my trailer two lanes to the left than one lane to the left.)  Recall that from my position in the driver’s seat, the focal point inside its reflected notch is in the mirror’s upper right quadrant, 6/10 up the mirror’s height, close to its inner (right) edge.  Its V-shaped notch is formed by the image of the large left mirror’s support arm and the left side of my tractor where the arm is attached.

Out of an area bounded by the outer (left) edge of the mirror extending from 4/10 to 7/10 of the mirror’s height, the lane image originates from a location even with my tractor’s left steer wheel.  As the image leads to a location behind my trailer’s tail in the mirror, it runs diagonally upward in a line above and alongside the image of the first lane to the left of my lane (and thus at a shallower, almost level upward angle), shrinking in size and converging to the focal point.  Reflecting the greater distance from my truck, the lane’s image is smaller, about 4/10 the size of the image of the first lane to my left.

When You Pass Me

Vehicles gaining on my truck in the lane two lanes to the left of my lane from just behind my trailer’s tail first appear only as specks in the focal point.  As vehicles advance in that lane, their images expand and move from the focal point in a downward diagonal path toward the mirror’s lower left quadrant.  The images travel in a path above and alongside the path of images of vehicles in the first lane to my left and thus at a shallower, almost level downward angle.

When the vehicles get even with my tractor’s left steer wheel, their images exit through the mirror’s outside (left) edge from an area whose base (bottom) is 5/10 up the height of the mirror.  By the time they exit, images of vehicles two lanes to my left have grown to about 4/10 the size of vehicle images in the first lane to my left.  From the base (5/10 up the height of the mirror) exiting images of low profile sport cars and compacts extend to 6/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend from 8/10 to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base to 10/10 of the mirror’s height.

The Right Fender Mirror

Similarly on relatively straight and level stretches of highway, in the right fender mirror I can see the image of the lane two lanes to the right of my lane extending from just behind my tractor’s right door to about 30 feet (approximately 2 compact-size 14 1/2-foot car lengths) behind my trailer’s tail at the focal point.  (The wide sight angle from my position in the driver’s seat to the right fender mirror enables me to see farther behind my trailer two lanes to the right than one lane to the right.)  From my position in the driver’s seat, the focal point inside its reflected notch (described above) is in the mirror’s upper left quadrant, 6/10 up the mirror’s height, close to its inner (left) edge.

Out of an area bounded by the outer (right) edge of the mirror extending from 2/10 up the height of the mirror to 6/10 up its height, the lane image originates from a location just behind my tractor’s right door.  As the image leads to 30 feet behind my trailer’s tail in the mirror, it runs diagonally upward in a line above and alongside the image of the first lane to the right of my lane (and thus at a shallower, almost level upward angle), shrinking in size and converging to the focal point.  Reflecting the greater distance from my truck, the lane’s image is smaller, about 4/10 the size of the image of the first lane to my right.

When You Pass Me

Vehicles gaining on my truck in the lane two lanes to the right of my lane from 30 feet behind my trailer’s tail first appear only as specks in the focal point.  As vehicles advance in that lane, their images expand and move from the focal point in a downward diagonal path toward the mirror’s lower right quadrant.  The images travel in a path above and alongside the path of images of vehicles in the first lane to my right and thus at a shallower, almost level downward angle.

When the vehicles get just behind my tractor’s right door, their images exit through the mirror’s outside (right) edge from an area whose base (bottom) is 5/10 up the height of the mirror.  By the time they exit, images of vehicles two lanes to my right have grown to about 4/10 the size of vehicle images in the first lane to my right.  From the base (5/10 up the height of the mirror) exiting images of low profile sport cars and compacts extend to 6/10 to 7/10 up the mirror’s height while images of higher profile personal vehicles extend to 8/10 to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base through the entire 10/10 of the mirror’s height.

When I Pass You

When I pass vehicles in the lane two lanes to the left or right from my lane, the vehicles’ images reverse their exit path in the respective fender mirror.  Images of vehicles two lanes to the left of mine enter the left fender mirror through the mirror’s outside (left) edge from an area whose base (bottom) is 5/10 up the height of the mirror, when the vehicles have slipped back even with my tractor’s left steer wheel.  As the vehicles slide farther back, their images shrink in size and recede in a path above and alongside the path of images of vehicles in the first lane to my left (and thus at a shallower, almost level upward angle) into the focal point (where vehicles are just behind my trailer’s tail).  Images of vehicles two lanes to my left are about 4/10 the size of vehicle images in the first lane to my left.  On entry, images of low profile sport cars and compacts fill an area along the mirror’s outer (left) edge extending from the base (5/10 up the mirror’s height) to 6/10 to 7/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 8/10 to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base to 10/10 of the mirror’s height.

Images of vehicles two lanes to the right of mine enter the right fender mirror through the mirror’s outside (right) edge from an area whose base (bottom) is 5/10 up the height of the mirror, when the vehicles have slipped back just behind my tractor’s right door.  As the vehicles slide farther back, their images shrink in size and recede in a path above and alongside the path of images of vehicles in the first lane to my left (and thus at a shallower, almost level upward angle) into the focal point (where vehicles are about 30 feet, approximately 2 compact-size 14 1/2-foot car lengths, behind my trailer’s tail).  Images of vehicles two lanes to my right are about 4/10 the size of vehicle images in the first lane to my right.  On entry, images of low profile sport cars and compacts fill an area along the mirror’s outer (right) edge extending from the base (5/10 up the mirror’s height) to 6/10 to 7/10 up the mirror’s height, while images of higher profile personal vehicles extend from the base to 8/10 to 9/10 up the mirror’s height and images of trucks, buses and other large vehicles extend from the base through the entire 10/10 of the mirror’s height.

Seeing You Three and More Lanes Away My Lane

Since they are “out of range,” i.e. outside the Caution Zones (see the Caution Zones chapter), vehicles three or more lanes away from my lane are of little concern to me.  Compared to images of vehicles one or two lanes away from my lane, images of vehicles gaining on my truck in three or more lanes away first appear in my truck’s mirrors at successively greater distances behind my trailer in successively smaller sizes and cross my mirrors in successively higher paths.  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.  With mirror views on my right side more constricted, images of vehicles in lanes to my right first appear at greater distances behind my trailer than those in lanes to my left.

Takeaways

Truck drivers have limited and somewhat complicated views of lanes and traffic to their left and right.

It is 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.

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