Four-wheel drives might be safer for owners, but not for others on the road

An anomaly in Australia's tariff regime means that four-wheel-drive buyers also benefit from a tariff rate 10 per cent lower than the import duty on passenger cars - effectively a tax break for those who buy more dangerous vehicles.

One solution would be, until all vehicle tariffs are reduced to zero, for new four-wheel-drives to bear a tax equal to the difference between the tariffs on cars and four-wheel-drives.

And state governments should adjust registration charges so that four-wheel-drive owners pay the full cost that their vehicles impose upon others. If it can be shown that four-wheel-drives cost fewer lives in sparsely populated rural areas, the impost should be lower in these places.

One of the great successes in Australian public policy has been our ability to bring down the road toll.

Thanks to random breath-testing, seat-belt laws, airbags, and tough enforcement of speed limits, the fraction of the population killed on our roads each year is half of what it was in 1985.

By stemming the four-wheel-drive arms race, we can keep this deathly figure from rising again.