In 2017 I was asked by Avon & Somerset Police to investigate the failure of a front offside (front right) tyre on a lorry that swerved out of control, crossed over the central barrier of the M5 motorway north of Bristol and collided with oncoming cars. 5 people in those cars died.
I found that both the front offside and the front nearside tyres were 18¼ years old.
The tread of the front offside tyre had been delaminating (separating) and ultimately the tread had started to peel off, exposing the underlying casing ply which then burst open. As always with lorries, buses and coaches, the vehicle veered sharply across to the side of the deflated tyre despite the efforts of the driver to resist the steering pull.
Once again, I found that the tyre failure was mostly attributable to ageing of the tyre.
I also found that the front nearside tyre’s tread had partly torn away, but it had only done so during the accident. However, I considered the ease with which it tore away to be surprising.
A further examination commissioned by DfT found that there had been significant deterioration of the rubber in the tread of both tyres (worse in the failed front offside one).
Following a coach crash in 2012 where I examined a 19½ year old front tyre and concluded that it had failed as a result of its age, there was pressure to ban the use of tyres that were 10 years old from the steered axles (the problem position on lorries and PSVs). I lobbied the Secretary of State for Transport and DfT to fund research into ageing of large tyres to find an appropriate maximum age, but all that resulted at that time was advice only for coach operators not to have such tyres on the front axle and to use them only on rear twinned wheel positions.
In my view, whilst helpful, that advice was illogical as it did not apply to lorries; that was sadly borne out by this 2017 lorry accident. I contacted the current Secretary of State to point this out. However, the week before the inquest into the M5 tragedy, DfT (who also gave evidence at the inquest) announced that the 10 year advice was being extended to commercial vehicles as well as buses and coaches.
DfT have announced that they are considering legislation to ban tyres over 10 years old from ‘larger vehicles’ including HGVs. However, in my view, legislation should apply not only to larger vehicles but should apply to cars/vans too. Additionally, it should apply to caravans, trailers and motor-homes, as they often have infrequent use and therefore can have treads with a (pattern) depth well in excess of the legal minimum despite the tyres being very old.