Researchers who analysed 10,000 crashes say car size does matter

You may have noticed that big cars are popular in Australia. 

Sales of sedans and hatchbacks have followed the US trend into a long-term decline, changing the shape of our national passenger fleet. 

Pedestrian deaths have started rising in the US and, to a lesser extent, in Australia, leading to questions about the effects of this shift in popular car design.

A new study of more than 10,000 crashes could provide some clues.

To see how cars have changed, let's compare different car models over the years.

You will see them get longer and heavier, but when it comes to the safety of the woman and child pictured, the most important dimension to watch is their height.

When we turn back the clock to 2005, the most popular car was the sedan. 

You can see the woman is taller than the car, which is less than 1.5 metres high and weighs nearly 1.7 tonnes. 

If she were to be hit by it, the impact would likely be lower on her body — for example, her legs or waist — rather than her head. 

Ten years later, SUVs are on the rise. 

This is a 2015 medium SUV at a height of 1.7m and it tips the scales about the same point as the sedan from 10 years ago.

So, it's not huge. 

SUV sales overtook more traditional cars in 2017 and have continued growing in popularity ... and size. 

New Australian research shows that as our vehicle height grows, the risk to pedestrians does too.

For every 10cm of vehicle height, the odds of a pedestrian death rise by 11 per cent.

Last year, this ute was the most popular choice among Australian buyers. 

At about 1.9m, it's 30cm higher than the average woman or 15cm taller than the average Australian man. This means it towers over most pedestrians. 

And as our car trends follow the US, these large pick-up trucks are also becoming more common on our roads. 

This 2026 model stands about 2m high and weighs up to 3 tonnes.

And while they can be useful for towing or other heavy-duty jobs, the reality is that many are spending time in heavily populated areas.

You will have noticed the bonnet shape change over the years, from low and sloping to higher and blunter.

A US study of crash data found that for every 10cm increase in front-end height, the risk of pedestrian death increased by 22 per cent, with women, children and seniors more at risk than other people. 

Australian crash data showed no significant association between vehicle height and weight, and men's fatality risk. 

But for women, an increase in either of those two dimensions became "significant predictors of death", according to the researchers (more so for height than weight).

We don't have bonnet-height crash data in Australia, but we do now have analysis linking taller cars to increased risk of death. 

Will Australia continue to follow US trends?

Like the US, the number of pedestrian deaths in Australia has risen in the past five years (after years of trending down), while the fatality rate for passengers inside a vehicle has roughly stabilised.

Melbourne University researchers wanted to explore if there was a particular factor behind this trend. 

They looked at 10,376 crashes between 2012 and mid-2025 in Victoria, including details such as vehicle type, road environment, speed limits, time of day and the characteristics of drivers and pedestrians involved. 

When looking at vehicle type, they found station wagons carried a probability of pedestrian death 1.2 times that of passenger cars such as sedans and hatchbacks, and for utes the figure was 1.6 times.

When they modelled the outcome of crashes that only differed in vehicle size, they found that every 100kg of vehicle weight increased fatality odds by 6 per cent, and for every 10cm of vehicle height, the odds of a pedestrian death rose by 11 per cent.

The previous US study's finding on overall height was weaker than the Australian figures (6.6 per cent increase in fatality odds per 10cm of height), suggesting if Australian data on front-end height was available, it could show a stronger fatality association than the US data.

Associate Professor Milad Haghani, one of those behind the Australian study, says one of the main reasons for the increased risk is the point of impact on a human body.

"If the point of the crush is to the upper part of the pedestrian's body, and also if the pedestrian doesn't end up on the bonnet and instead ends up on the ground hitting their head on the concrete, those are elements that can increase the likelihood of fatality," he says.

They found women are disproportionately impacted because they are, on average, shorter than men, so their head and torso are at a critical point of impact.

Professor Haghani explains that a crucial finding was that the fatality risk remained, even in lower-speed crashes.  

"These are otherwise survivable crashes that are turning fatal as a result of vehicle design."

Researchers estimate that if cars remain at those early and mid-2000s heights and weights, it could save about 9 per cent of the lives lost.

"Some people might say that, 'Oh, well, you're at a higher level as a driver, you should see that', but that is not the case," Professor Haghani says.

"You see further down the road where it doesn't matter, but you don't see much right in front of your vehicle, which matters the most."

Last year, the Australasian New Car Assessment Program (ANCAP) tested five large utes as part of its safety rating process.

The utes all met Australia's road vehicle standards, but ANCAP chief executive Carla Hoorweg says there could be improvements.

She says improving safety is about ensuring vehicles have the right crash-avoidance technology to prevent a collision in the first place.

The utes underperformed in simulated scenarios of a child running in front of the vehicles at night and the driver's vision while the utes were turning.

"Where we see vehicles falling short is that they tend to have the technology, but it doesn't work in the breadth of scenarios of vulnerable road user dummies," Ms Hoorweg says.

Ms Hoorweg says one of the biggest risks to pedestrians is older cars that don't have as many safety features as newer vehicles.

Victoria Police Road Policing Assistant Commissioner Mick Hermans says too many pedestrians are being killed or seriously injured, but that there is a range of factors at play. 

"We tend to see a mix of both drivers and pedestrians at fault in fatal pedestrian collisions, with drivers most likely to fail to give way to pedestrians, while pedestrians are opting to cross a road mid-block rather than at a designated crossing," he says.

He says motorists need to pay attention to their surroundings, especially in built-up areas, and pedestrians need to look up when crossing the road and use designated crossings.

So what are the solutions? 

The National Transport Research Organisation has called for a review into the safety standards of large utes.

ANCAP is working on its next three-year vehicle safety protocols, which could include factors such as bonnet height, use of technology, Automatic or Advanced Emergency Braking and car design.

The Melbourne University researchers propose a range of solutions, including removing tax concessions, revising import safety regulations, and introducing specific licence conditions for large vehicles.

"The big cars have the momentum, and without any change in policy, the momentum is not going to go away," Professor Haghani says.