‘Warning signs not effective’

Press, Volume CXIV, Issue 33650, 27 September 1974, Page 12

‘Warning signs not effective’

No great confidence should be placed in the effectiveness of road warning signs, says a research report by the Ministry of Transport.

Drivers .seemed to be unable to retain sign information for as long as it applied, the report says. The research was carried out on a straight flat section of sealed two-lane highway, with a 55 m.p.h. speed limit for cars and reasonably wide metal shoulders, near Foxton in the North Island. The' landscape was described as “typical New Zealand rolling farmland with only isolated houses.” Two hundred drivers were stopped and asked to recall sigsn parsed about a quarter mile back. In no cases did the probability of recall approach 50 per cent. Mr J. E. Sanderson, who prepared the report, says that drivers interviewed were better able to recall signs containing symbols rather than words, but thus could not be generalised. Significantly fewer drivers were able to recall one advertising sign included in the study. “The only interpretation that can be placed on the results is that the signs studied were not effective in

conveying their messages,” says the report.

The drivers might have failed to recall signs just passed because failure to heed them would not have posed dangers to the drivers.

In this case the motivation to retain the message until interviewed would probably have been comparatively low. “Failure to register and act on other types of warning signs such as advisory speed limits, could result in more dire consequences. Whether this would result in improved recall is worthy of study,” says the report. Failure to register the sign's information did not mean that drivers had not seen the sign. It could not be assumed that a well-designed sign legible from greater distances would be more effective.

The report suggests that duplication of the same sign, or of the same sign message in different forms — words and symbols — or painting on the road might increa.se the probability of the message being retained. The survey did not yield evidence that advertising signs on roadsides distracted attention from driving, because recall of advertising signs was lower than that of road signs, the report says.