Business drivers are more likely to tailgate and speed on motorways and residential roads, according to new figures.
Three-quarters of at-work drivers admit to speeding on motorways, with an even greater number (77%) speeding through 30mph zones.
A further 61% admit to leaving less than a two-second gap between their vehicle and the driver in front.
Polling nearly 5,000 drivers, half of whom drove for work, a joint survey by road safety charity Brake and Green Flag found that business drivers outstripped general motorists on each count.
The survey did not ask business drivers why they behaved so poorly behind the wheel but Brake indicated that deadlines and other pressures were to blame.
“Work pressures are no excuse for impatient and aggressive driving,” said Cathy Keeler, head of campaigns at the charity.
However, fleet manager’s association ACFO has defended the efforts of its members to manage the occupational risk posed to their drivers.
Julie Jenner, ACFO chairman, said: “With company car drivers there has always been the pressure to perform and no doubt there are still some drivers who still take risks as part of their day-to-day job.
"But the duty of care message is getting through to fleet managers. The majority of speeding incidents are because of that driver’s way of driving.”
John Pryor, fleet manager at Arcadia Group, said individual driving style was a more likely influence on Brake’s figures, rather than company pressure or lax fleet management.
“Drivers have a responsibility to make sure that they are adhering to the law,” he said.
Steve Johnson, head of communications at DriveTech, said: ”Employers cannot monitor driver behaviour every minute of the day.
"Fleet managers should empower drivers to make sensible, rational decisions about their welfare whilst they are on the move, through a combination of education, information and retribution.”