Dangers of snow tyres need to be addressed
Cars with snow tyres need to be flagged and their risks identified, the parents of a Nelson woman who had a bad crash in a car fitted with the tyres say.
Lucy Stronach was driving to Christchurch in a Suzuki Swift she had recently purchased on Trade Me when she crashed in the Lewis Pass.
It was raining, and she was in traffic when she slowed down for a corner. Her car slid across into the right-hand lane and spun out ending up on its side in a ditch.
Lucy's mother Joy Stephens said the accident could have been more serious, if not fatal.
"If a car was coming the other way when Lucy skidded into that lane she could have died," said Stephens.
The car was purchased with four snow tyres fitted. A coroner called for a ban on snow tyres in 2011 after a fatal accident where a car with snow tyres slid into the path of an oncoming vehicle.
Lucy put the accident down to taking the corner too fast in an unfamiliar car, despite being under the speed limit.
Those following her were surprised she had lost control as they were travelling at a similar speed.
When she got the car back from the panelbeaters seven weeks later it still felt slippery on the road, particularly in the wet.
Lucy's father Wayne Stronach discovered the car had snow tyres fitted and that they were not suitable for use outside of an alpine environment. He also discovered snow tyres were the cause of several fatal accidents in New Zealand.
Stephens said while snow tyres were legal she believed they were dangerous, especially in the wet, and she wanted people to be aware of their risks and the rules around their use.
To the untrained eye they looked like standard tyres.
A VTNZ pre-inspection report found the car was mechanically and structurally sound and in good condition for its age.
It noted the car had snow tyres fitted, but it was not mentioned in the inspector's notes to be of any concern.
Had the tyres been flagged as a safety concern they would have changed them.
"Normal people don't carry all that information in our heads," said Stephens. "We don't think people are informed because there is an issue with these tyres in the wet."
In the future, Stephens would like to see better information about snow tyres flagged in a warrant of fitness or on a pre-inspection report.
New rules concerning the use of snow, or winter tyres came into effect in April 2010.
A Ministry of Transport spokeswoman said if a vehicle had snow tyres, they had to be fitted to all the vehicle's wheels. The tyres also needed to have a tread depth of at least 4 mm.
Car tyres are checked when a vehicle is imported, and during the warrant of fitness or certificate of fitness inspection, and if a vehicle with winter tyres does not meet these two requirements it will fail the inspection.
A car may get a warrant of fitness with snow tyres, also known as winter tyres provided they are not mixed with normal tyres and have a minimum tread depth of 4 millimetres compared to the 1.5 millimetres required for standard tyres.
Following a car accident which resulted in the death of William Henry Paul in 2010, an inquest by coroner Tim Scott found snow tyres had been a major factor in the crash and recommended they be banned for use on cars in New Zealand.
READ MORE: Death prompts new call for ban on snow tyres
Paul was a front-seat passenger in a Toyota Corona fitted with four snow tyres when it slid on a corner and collided with a courier van on State Highway 56, near Taumarunui, in August 2010.
The New Zealand Transport Agency states winter tyres are made with a softer rubber compound than standard tires and have deeper treads specifically designed to maintain grip in cold weather, below 7 degrees celsius.
Winter tyres provide better grip than the traditional summer tyres in ice, snow and cold weather, but will provide less grip than summer tyres in non-wintry conditions.
They have a distinctive square-patterned tread and are usually marked with a 'snowflake and mountain' symbol, or the word 'studless' on the sidewall.
A spokeswoman for the Ministry of Transport said anyone selling a vehicle should advise the new owner if the vehicle has winter tyres fitted but it is up to the vehicle owner to ensure that they are using the appropriate tyre type for both the vehicle and the current road conditions.
If a vehicle owner is not sure what type of tyres are on their vehicle, they should seek advice from a garage or tyre retailer.
Information from the NZ Transport Agency says the vast majority of New Zealand motorists don't need winter tyres on their vehicles. They may be appropriate for a small number of motorists who regularly drive in wintry alpine conditions but they should be changed to conventional tyres at the end of the winter.
Legal requirements for winter tyres
- If you need winter tyres, they must be fitted on all road wheels
- Winter tyres must have a tread depth of at least 4 mm
Beware of older 'new' or used winter tyres. The soft rubber tread compound can harden, resulting in less grip and making the tyres dangerous to use.