A three-month trial of a 50km/h speed limit will begin in Queanbeyan and some other NSW centres soon. The ACT has said it will watch the trial carefully.
It is a pity we have to wait for a trial when the case for a reduction is so clear. Alas, it seems necessary to prove that the laws of physics apply in each and every country, state, province and territory. That proof has to be demonstrated mainly to politicians — who fear the vote-changing wrath of the minority who vigorously oppose speed reductions — rather than the broad mass of people who generally approve speed-limit cuts.
Sixty-two per cent of Australians agree that the limit should be lowered, according to a Federal Office of Road Safety survey. The people most in favour of the same or a higher limit are those aged 15 to 24 — the very people involved in the highest proportion of accidents.
Australia has one of the highest suburban limits in the world, largely through historic accident. It was raised arbitrarily in 1964 from 30mph to 35mph because of car and road improvements, though no account was made for the immutable and finite capacity of the humans in the car to absorb the information at the faster speed and respond to it. Then in 1974 with metrification the 35mph (56km/h) limit was rounded up to 60km/h with no reference to safety.
It is a question of physics. A reduction in speed results in a huge reduction in impact likelihood and force. If one car is travelling 60km/h and another 50km/h both brake at the same time, the car doing 60km/h will be doing about 40km/h at the point at which the other car has stopped. The force of the impact increases exponentially with speed.
A 1994 study by the NHMRC Road Accident Research Unit, the University of Adelaide and the Federal Office of Road Safety found that 32 per cent of pedestrians killed in 60 km/h zones would probably have survived if the vehicle had been travelling just 5 km/h slower before the emergency. When Denmark cut its limit from 60 to 50, pedestrian deaths fell 24 per cent. Death rates among hit pedestrians in countries with a 60km/h limit are more than 40 per cent higher than in 50 km/h limit countries.
The 60km/h limit is particularly nasty for the vulnerable in society _ the very young and the aged. These people who are less mobile and less able to cope with traffic are the very people who stay close to home in the suburban streets. Suburban streets become the place for their casualties (injury or death): 73 per cent of young cyclist casualties are on suburban streets; 65 per cent of young (0-16yrs) pedestrian casualties and 50 per cent of elderly pedestrian casualties. Of course, the new limit has to be enforced to be effective, but it should apply only where there are houses on both sides of a single-carriageway. It should not become a revenue-raising device on more open suburban arterials. But even without any greater enforcement measures, speeds will fall. The law-abiding will come down 10km/h from 60 to 50; the risk takers will come down from 70 to 60 and the lawless will come down from 80 to 70.
Why not 40km/h or 30km/h? The reason is that the 60 to 50 drop it has a huge effect on death and injury compared to a tiny inconvenience, which is unmatched at the lower levels which would require much greater inconvenience for less benefit.
One of those factors is the amount of information that has to be processed by the brain. In the context of a suburban street, with kids, dogs, signs, side streets and other traffic, there is too much information at around the 60km/h mark and a slight reduction in speed makes the amount of information manageable so that reactions are more effective.
A speed reduction would also cut noise, generally improve the environment in residential areas and discourage commuters from using local roads as thoroughfares.