More than a quarter of motorists text while driving, with those using cars for work more likely to offend.
And more than one in seven say they apply make-up or shave while at the wheel, the survey by road safety charity Brake and insurance company Direct Line found.
Of those who used a vehicle for work, 31% said they texted while driving compared with a figure of 28% for non-work drivers.
A total of 17% of for-work drivers admitted to attending to personal grooming while at the wheel compared with 14% for non-work motorists.
Drivers using vehicles for work were more likely (37%) to talk on hands-free mobiles while on the road than non-work drivers (24%).
The poll also found that 54% of for-work road users admitted to speeding on 60mph roads, compared with 34% for non-work drivers.
Also, 76% of for-work drivers admitted to speeding more than 5mph above the limit on 30mph roads, compared with 62% of non-work drivers.
Brake deputy chief executive Julie Townsend said: "It is appalling so many people who drive in a professional capacity are taking such horrendous and unnecessary risks.
"People who drive as part of their job should be taking great care.
"We are urging all employers to ensure they have comprehensive safe driving policies in place."
Direct Line spokesman Matt Owen said: "The risk that those who drive as part of their job are taking with their lives and the lives of others is substantial."
