Drivers are bombarded from a variety of media with imagery that competes effectively to capture and hold their attention. But the one area in which effective messaging can be a matter of life and death—road signage—the need for critical review is ever present.

 

In large cities the lettering styles, size, colour and location of street signs may vary from one neighbourhood to another. For a driver visiting an area for the first time, crossing a neighbourhood border and making the adjustment to another signage method may be just one more challenge in an already difficult matter of getting to a new destination. For instance, heritage neighbourhoods may have signage that was designed primarily to meet the needs of pedestrians. This is great for walking tourists but difficult for visiting drivers.

 

A recent newspaper report on the problem of the lack of street sign standardization between and within Canadian cities identified the key factors that make for effective road signage. Lettering size is crucially important to legibility. Traditional road signage has letters that are 10 cm (approximately 4 inches) high. Signage experts say that this allows the average downtown driver two seconds of warning between comprehension and, for example, arriving at an upcoming intersection. The “two second rule” means that on streets without left turn bays, those annoying drivers who fail to signal until the very last moment, in fact may be reacting as fast as is humanly possible.

 

The trend in newer signage seems to be towards characters that are roughly twice the size of traditional signs, that is, 20 cm or 8 inches high. Traditional road signage has generally used all capital letters. New signage is moving away from this system, with lettering that is upper and lower case—traditional text style. Studies have shown that word shape based on the pattern letters with variation on the height of letters, is actually more important for word recognition than letter-perfect spelling.

 

Colour is also critical, and may have been established on the basis of assumptions from long ago, rather that any real scientific analysis. North American highway signage is almost universally white on dark green. White on dark blue is also effective. Red, white, yellow, and black are reserved for traffic control signage. Signage colour may increasingly become the focus of effectiveness studies.

 

None of this is to say that in any particular way current signage is no good. Just that there will always be room for improvement. Please drive safely.