Fleet managers are more likely to be restricted over the hours that their employees can drive following agreement at the EU Council of Ministers reforming the EU working time directive.
The Government, which has long opposed a strict EU maximum 48-hour working week, has agreed to changes, although it still retains an opt-out.
The Department for Business, Enterprise and Regulatory Reform, was adamant that the, while it has agreed to new terms, the right for UK workers to choose to work longer than 48 hours a week is still secure.
Business secretary John Hutton said: "This agreement means that people remain free to earn overtime and businesses can cope during busy times.
"Securing the right for people to work longer if they choose to do so is hugely valuable to the British economy."
The agreement sets a cap of an average of 60 hours for those who have opted out, and sets new conditions on the use of the opt-out.
Workers will not be able to sign away their rights in the first month and the opt-out will need to be renewed each year.
Also, the UK has relented on its opposition to extend permanent employee rights to temporary workers.
Under another council agreement, these would be granted to temporary employees after 12 weeks of work.