Police are warning people in Devon and Cornwall to take extra care on the roads following the clock change.
The time change - in the early hours of Sunday - will mean that although it will be lighter in the mornings, the nights will draw in earlier too.
A police spokesman said: "Cyclists and pedestrians are particularly at risk when daylight hours reduce in winter.
"Cyclists should check that they have suitable lights and that they work correctly."
Officers will be carrying out checks on cycle routes to ensure that cyclists are visible and that they have the correct lights fitted and working.