What constitutes good vision through a truck’s mirrors depends on whose eyes you look through. Truck engineers tend to use the “95th percentile” human as their model-typically a man about 5 feet 10 inches tall. If mirrors are made to accommodate that man as he sits in a typical truck seat, most of the rest of us can adapt to the situation. In this case, the seat and the mirrors can be adjusted so someone taller or shorter can still see out of them.

If you go to buy a truck, you can bet the mirrors will meet government standards as to size and design of the basic West Coast flat-glass mirrors.

However, you can’t specify that any mirror you buy-including aftermarket add-ons-meets some sort of standard as to outward visibility because there is none.

Happily, the instinct for survival seems to have kept the industry ahead of government regulations on this score. Here are some examples:

MOTORIZED MIRRORS

Several brands appeared in the early ’80s, and some died almost as fast as their mechanisms failed-victims of vibration, road spray, and dockside beatings. However, one brand, MotoMirror, persisted with improvements to its product and its sales pitch.

Truck builders saw the trend and began designing their own, primarily for use on aerodynamically styled tractors (usually these are made by outside vendors).

Today, motorized mirrors have dual-axis drives that move the glass up and down as well as side to side.

Some products have motorized flat glass and convex surfaces, each two-way adjustable. This range of adjustments adds convenience, especially when the right-hand mirror gets vibrated or banged out of adjustment, or when the co-driver takes over and finds the mirror is not set to his or her liking.

Innovation hasn’t stopped with acceptance, however.

One company, Ultra-View Mirrors, has a mirror that automatically moves to keep the rear corner of the trailer in view, using sensors to track the trailer (manual controls can override the system). Designed for 17-inch bracket attachments, the mirror is available in both West Coast and aerodynamic shells.

GLARE REDUCTION

Glare from headlamps has gotten worse since cars and trucks went to halogen lamps. One effective glare-stopper is the TruDim mirror from Mirror Systems Inc., which uses dichroic liquid crystal display technology. The mirror’s reflectance is reduced by electronic stimulation of liquid crystals, so drivers can dim glare instantly with the turn of a switch.

TruDim mirrors have been offered only through Freightliner for the past three years. The exclusivity deal is scheduled to expire next year.

HEATED GLASS

No image is of any use if it’s obscured by moisture or ice.

Heated mirrors, which have been around for more than two decades, use a simple, flat heating element applied to the rear of the glass. With a flip of a switch, electric current flows through the element, heating the glass.

However, devices that wipe away water or blow it off the glass haven’t caught on, probably because their mechanical complexity offsets the advantage offered.

SPOTS

Should you festoon the front of your tractors with auxiliary convex spot mirrors, whose brackets look like misplaced fishing poles? Yes, if the make and model of truck you buy comes standard with smallish windows and blind spots. No, if the vehicle has large windows, a steeply sloping hood, and other features that reduce the blind-spot problem.

And yes, if corporate lawyers warn that not having them gives the appearance that your company doesn’t care about reducing painful accidents.