April 1, 2013 10:00am by David Farrar

The Press on open road speed limits

For as long as many people can remember, the open-road speed limit for driving in this country has not changed. It has not increased significantly since the late 1960s when it was raised, under the old imperial system, from 55 miles per hour to 60mph – the equivalent of 96kmh, so not significantly different than the 100kmh that applies today on highways and motorways.

Umm, that is missing out a big chunk of history. The open road limit may have been 60 miles per hours, but in 1973 due to oil shocks, it dropped to 80 km/hr or 50 miles/hr.

It was only in 1986 it went to 100 km/hr.

So far from the open road limit rarely changing, the changes have been:

1962 – from 50 mph to 55 mph
1969 – from 55 mph to 60 mph
1973 – from 60 mph to 50 mph or 80 kmh
1986 – from 80 kmh to 100 kmh

Consider the cars that Kiwis were driving when the speed limit was last raised.

There is a world of difference between the engineering and safety standards of 21st-century cars and the likes of the Morris Minor, the original Mini, the Ford Cortina, the Holden Kingswood, the Rover 2000 and the Hillman Imp. Road engineering, too, has improved during those decades. Seen in this context, a proposal to raise the limit by only 10kmh on a relatively small number of top roads can be seen as very modest.

The difference in car safety and engineering is massive.

The speed limit is a maximum, not a target, and the rules – so often observed mainly in the breach – state that people should drive at a speed under the limit that is appropriate to the road, traffic, weather and other conditions.

If the speed limit is increased on engineered motorways, this should not be taken as an indication to drive at 110km on the open road or rural highways, where a 110kmh speed limit would not be appropriate.

Yep – drive the the conditions. Sometimes that will be 110 km/h and sometimes 70 km/h.