Nearly three-quarters of motorists lost concentration while on the road last year, according to Brake.
The worrying findings of the road safety charity's survey have prompted calls to drivers to be extra careful at the wheel this busy bank holiday weekend.
Annoyance caused by other careless road users, workplace pressures and stressful situations at home are some of the reasons why drivers are unable to pay their full attention to what is happening around them, the study found.
Brake said 71% of all motorists it polled admitted to having lost focus at some point while driving last year.
Distractions caused by passengers was cited by 42% as the reason for losing concentration.
Brake senior campaigns officer Ellen Booth said: "Every death and serious injury on the roads is devastating and tears families apart. All too often these casualties result from careless errors that could easily be avoided if drivers gave their full attention to the road.
"If you are so upset or angry that you can't give driving your full attention, you need to pull over and cool off."
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