Are SUVs making our streets safer?

That could be the conclusion you’d draw if you looked at the statistics for 2013.

SUV sales are up 8.3 per cent. They now account for 29.7 per cent of all new cars sold, according to new data from the Federal Chamber of Automotive Industries, released today.

All that bulk and all that mass and the inevitable blindspots you get from behind the wheel of a two-tonne lump should mean worse road safety outcomes. But the road toll is down sharply.

In Victoria it has fallen to 212 in 2013 from 261 at the same stage in 2012, a fall of 19 per cent. The period between December 3 and December 31 accounted for 26 road deaths in 2012, taking the end of year total to 287. Even cyclist, motorcyclist and pedestrian deaths are down, from 81 to 71. It seems certain that road deaths will finish the year well below last year’s total.

NSW is in a similar situation. Its toll has fallen from 342 to 315 over the first 11 months of the eyar.

In Queensland the result is less dramatic, down from to 258 to 255.

Even in WA, where you imagine mining money funding a lethal combination of V8 utes and top-shelf rums, the toll is down from 167 to 149.

How can this counter-intuitive situation be explained?

The most popular SUV sold in Australia this year is the Mazda CX-5, with over 18,000 rolling off the lots.

It weighs around 1500 kg. But it comes with electronic brake force distribution, emergency brake assist, six airbags, blindspot monitoring, land departure warning, and dynamic stability control.

Side curtain airbags and electronic stability control are two of the features emphasised in the How Safe is Your Car campaign, run by the Victoria’s Transport Accident Commission (TAC).

“If all vehicles were fitted with ESC, single vehicle injury crashes could be reduced by approximately 30%, saving about 50 lives in Victoria each year,” The TAC website says, citing evidence from the Monash University Accident Research centre.

So SUVS are making the streets safer. But nor because they are SUVs. Just because they are new.

What’s really happening is that Australians are using their world-beating wealth to replace their old cars with new ones. Each year for the last three years, over a million vehicles have been sold in Australia. Cars seem to have been immune to general consumer caution.

New cars are safer, in part because the TAC has been nagging Australians to buy safer cars. (Although it doesn’t nag people to buy smaller cars).

The TAC, established in 1986, has been a crucial part of the ability of Australia to drop the national road toll from 3800 in 1970 to 1300 in 2012. It is an insurance company that is statutorily required to make payouts regardless of fault, giving it the strongest economic incentive to reduce accidents regardless of cause. This harnessing of incentives makes it a uniquely effective piece of the public policy apparatus and Victoria’s roads are regarded as among the safest in the world.

The TAC is currently targeting P-Platers (novice drivers), the next big area in which it thinks improvements can be made.

But while it harvests low-hanging fruit, the move to bigger and heavier cars creates a longer-term issue.

As more people drive a heavy car with a large crumple zone and an elevated driving position, encouraging people to get back into smaller lighter cars that can do less damage is going to be harder than ever. The data don’t break down deaths by type or weight of car, but I doubt they are concentrated in SUVs. If two modern cars with five star ratings crash, physics suggests you’d be better off in the bigger one.

If the TAC eventually decides that safety technology is maxed out, and moving people to lighter cars is the next lowest hanging fruit, it will be trapped on the horns of a game theory dilemma.