New laws come into force on Sunday that should protect company car drivers and those who use their own cars for work.
The Corporate Manslaughter and Corporate Homicide Act will force companies to make efforts to protect employees who drive for them.
However, new research from fleet management firm Arval shows that, while most firms are ready for the new laws, some are not.
The big issue is insurance on cars that belong to so-called 'grey fleets'. These are privately owned cars used for work, rather than company cars.
Since Arval's previous survey in October, 6% more companies are checking that drivers of non-company vehicles used for work have the correct insurance - but there are still many who have not.
Jenny Powley, director of Arval's large corporate group, said: 'Grey fleet vehicles that are unsafe and not fit for purpose put employees and other road users at risk. However, it is encouraging that the message we have taken to the market is starting to have an effect'.
The good news is that since the October survey, 46% of businesses that responded are reviewing their fleet duty of care, and a further 22% have already done so. Of these, 9% have not only completed a review, but have already implemented the necessary changes.