Listening to sport on the radio affects drivers more than being drunk at the wheel, research has revealed.
With Wimbledon in full flow, a flurry of cricket matches and World Cup football until the middle of the month, sports fans could be putting their lives at risk, according to the study.
The danger increases if the driver has an emotional or financial attachment to the result - such as supporting a particular player or team, or having a bet on the outcome.
In these cases, motorists' reaction times are 20 percent slower than normal, the study by the respected Transport Research Laboratory showed.
If travelling at a speed of 110km/h, this distraction would add six metres to a car's stopping distance.
The report notes: "To put this into context, this increase in distance travelled is 10 percent further than the additional stopping distance when driving with a blood alcohol level at the UK legal limit (80mg/100ml)."
The study reveals that during the testing, there were nearly 50 percent more incidents of hard braking while motorists were listening to sports commentary on the radio, compared with driving without any distracting factors.
The report states: "This suggests that the motorists were not paying enough attention to the road and had to make late decisions to respond to the conditions and drivers on the road around them."
It adds: "Worryingly ... while motorists were found to realise that other distracting factors, such as stress and attending to arguing children, impaired their confidence and safety while driving, they did not feel that listening to sports commentary on the radio had an impact on their concentration, confidence or safety."
TRL's Dr Nick Reed added: "It particularly tense times, such as a penalty shootout, it may be safer to find a safe place to park and enjoy the action without risking an accident."
The study followed the reactions of 18 participants (nine male and nine female) aged between 25 and 45.
Participants were asked to listen to the radio sports commentary of three consecutive horse races while driving.
Beforehand they were asked to choose a horse for each race and told that they would be paid £1.50 for each horse in the top five.
"This was done to maximise engagement with the sports commentary," said the report.
Andy Goldby, road safety expert at insurance firm Direct Line, which comissioned the study, said: "When you're a sports fan and are both emotionally and mentally engaged in the outcome of the match, subconsciously more of your concentration is likely to be on the radio than on the road.
"We hope that by drawing attention to the increased risk of distraction, drivers will pay more attention to the road and less attention to the game." - Daily Mail