Children travelling to school in Northern Ireland could be put at risk by proposals to move the clock forward, the public transport operator has said.
Time would move forward by an hour from GMT in the winter and a further hour in the summer, to match Central European Time, meaning lighter nights but darker mornings.
Westminster is considering the move, which proponents like sports organisations say would improve tourism and encourage outdoor activities in the evenings. Farmers in northern parts of the UK are among those opposed.
A submission from bus and train company Translink said: "The proposal would effectively mean darker mornings for longer in the autumn/winter, particularly in the mornings when most traffic is on the roads at one time, that is schools and commuters.
"This is potentially more risky for vulnerable groups such as schoolchildren."
Northern Ireland has shorter days than London in winter because it is north-west of the UK's capital.
MP Rebecca Harris is championing the Daylight Saving Bill in Parliament. The Northern Ireland Affairs Committee of MPs is considering the implications of her Private Members' Bill for Northern Ireland.
Among individuals and organisations submitting their views are Translink, which is responsible for transporting most of Northern Ireland's children to and from school.
Its statement to the committee added: "Darker evenings in our view are not as big an issue as the majority of our schools traffic is over by 4.30pm or 5pm and the evening traffic is more staggered, with most commuters making their homeward journey between 5.30pm and 6pm."
Organisations in favour of more research include the Royal Society for the Prevention of Accidents.