Sports fans, who may currently be distracted by coverage of Wimbledon, the World Cup and international cricket matches, may be putting themselves and the lives of others at risk.
The risk increases if the listener has an emotional attachment to a team or an interest in a particular outcome.
Reactions can be slowed by up to 20 per cent scientists at the Transport Research Laboratory (TRL) found – adding a six metre stopping time if a car is travelling at 70mph.
The report said: “To put this into context, this increase in distance travelled is 10 per cent further than the additional stopping distance when driving with a blood alcohol level at the UK legal limit (80mg/ml).
The number of incidents of hard breaking at the last minute almost doubled when motorists were listening to sports commentary.