Research conducted by Stafford-based driver training and fleet risk management firm Pro-Drive among fleet drivers has found the vast majority admitted that observation is their greatest weakness.
Researchers found 84% of drivers said looking at the road around them is their greatest failing, compared to 40% of drivers who said keeping safe distances is a major driving fault.
One-third of drivers said they fail to use their mirrors effectively, while other areas for concern include poor use of gears, 'coasting', approaching junctions too fast and lack of lane discipline at roundabouts.
The survey of 188 drivers, conducted as part of Pro-Drive's pre- and post-driver training assessment, also revealed that more than one-third of drivers had endorsements on their licences - mostly for speeding.
Graham Hurdle, managing director of Pro-Drive, said: 'For most company car and van drivers, the physical act of driving is so routine that they almost do it subconciously.
'As a result, when you are driving during the working day, your mind is elsewhere'
Pressure of work is a key problem when drivers are on the road during the day, as they attempt to rush between appointments.
Hurdle said: 'This underpins the message that driver training is not about teaching people how to drive.
'It is about working with fleet managers to identify the reasons why accidents happen and eliminating them.'