Benefits from seat belts indicated in study

Press, Volume CXIV, Issue 33447, 31 January 1974, Page 13

Benefits from seat belts indicated in study

(New Zealand Press Association?

WELLINGTON.

In the first 10 months of compulsory seat-belt use there was a levelling off in fatalities among front-seat occupants at a time when deaths of other road users increased substantially, according to a Ministry of Transport interim report.

The researchers, Messrs M. Ross Palmer and J. B. Toomath describe the interim report as “an analysis of the first 10 months operations of the compulsory seat-belt law based upon the rather limited data available so far.”

They say the most significant findings were:—

A doubling of seat-belt usage with the introduction of legal compulsion. A levelling-off in the number of fatalities to front-seat occupants, at a time when fatalities to other

road users were increasing substantially. A general reduction in the severity of injuries suffered by belted occupants, indicated by a two-month study of accidents attended by traffic officers.

The wearing of seat belts by drivers and front-seat passengers of post-January, 1965, cars became compulsory—with some exceptions—on June 1, 1972.

Steady increase Over the last 10 years there has been a steady increase in the number of seatbelts both fitted and used. After the compulsory-use law, it has been estimated that the proportion of belts used by drivers and front seat passengers more than doubled, the report says. Rural drivers have taken to seat belts more than have their urban counterparts.

In August, 1971, 33 per cent of rural drivers were wearing the belts fitted in their vehicles. This increased to just over 50 per cent just before the compulsory law came in, and to 90 per cent soon afterwards.

In urban areas only 30 per cent of drivers were wearing their vehicles’ belts in August, 1971. This rose to 33 per cent just before the law came in, and to 85 per cent soon after.

Up to 60 p.c. •‘lt can be concluded that since the compulsory-wearing law was introduced, the proportion of drivers and frontseat passengers of cars on New Zealand roads wearing seat belts has increased to about 60 per cent. “What the checks do not show is how many of the belts are worn incorrectly. "In some cases at least, it is suspected that the belt is very loose or may be over the driver’s shoulder but not actually buckled up, to make a show of complying with the law.” The researchers say that taking into account the exempted vehicles (mainly heavy traffic) it is likely that on a typical length of road about 50 per cent of vehicles will have drivers and frontseat passengers wearing belts —either correctly or incorrectly. They add: “Before the compulsory law it would have been about 25 per cent.’’

“Deaths reduced” On fatalities, the report says that before-and-after comparisons suggest that the compulsory law has been effective in reducing deaths of drivers and front-seat passengers. “Had the major increase of 44.3 per cent in fatalities to other road users not occurred, the over-all increase in the first 10 months of the compulsory law would almost certainly have been less than in recent years.” Fatalities among drivers and front-seat passengers in rural areas increased slightly, while there was a drop in urban areas. The researchers say this is probably partially accounted for by the fact that when compulsory use came in, urban usage rose 157 per cent, while rural usage rose 80 per cent (having started at a higher usage rate).

Adults most During the first two months of the new law traffic officers were required to complete a questionnaire for each vehicle in an accident they attended if that vehicle was so damaged that it could not be driven away. This criterion meant the survey was not biased by occupant injury, say the researchers. Three conclusions are drawn.— Adult drivers (90 per cent) had a higher seat belt wearing rate than either youths (84 per cent) or the elderly (83 per cent). Adult and elderly left-front passengers (92 per cent) had a higher wearing rate than youths (80 per cent) and children (27 per cent). The vehicles which young drivers used had a smaller proportion of belts fitted (43 per cent) compared with adults and the elderly (55 per cent). This was probably because young drivers tend to have older vehicles.

Injuries reduced The researchers say their figures show "that the chances of being injured or killed are higher when a belt is not used. In fact there was three times the proportion of serious and fatal injuries when belts were not used (16 per cent) than when they were used (5 per cent). "The proportion of minor injuries was about the same —23 per cent (not used) and 20 per cent (used). “Over-all, 25 per cent of belt users were injured,

compared with 39 per cent for non-belt users.”

Dealing with the way injuries were caused, the researchers say ejection rates were higher when belts were not used, and the proportion of injuries caused by windscreens was slightly higher. “Where belts were used there was a higher proportion of injuries involving the steering wheel and controls and the seat belt itself, but the total number of injuries for belt wearers was much lower.”

Trunk injuries There was a higher proportion of head injuries and shock when belts were not used, and also more multiple injuries. However, there was a higher proportion of trunk injuries among belt users. The small sample size made comparisons of different seat belt types of doubtful value, the report says. “The major differences observed were with front impact type accidents where lap belts did not seem to be as effective as the other two types, and in accidents involving rolled vehicles where

combination lap and diagonal belts produced a lesser proportion of injuries than diagonal belts.” Injuries caused by seat belts amounted to 12 among about 1300 cases studied, and all were minor. Summarising, the researchers say the conclusions can only be tentative at this stage because of the short time the compulsory law has been in effect, and because data for accident injuries is not yet all available. Five more aspects of research are proposed.— Whether belt usage makes drivers more reckless. Whether incorrectly-used belts increase the chances of injury in any way. Whether non-belt users are more accident-prone as a class. Whether the legal compulsion to use belts antagonises certain drivers and thereby affects their driving behaviour adversely. Whether any possible disadvantage arising out of the above four points outweighs the proven advantages of seat belts.