Calls have been made to enforce the law and get tough on cyclists who ride on the road without lights at night.
Exeter resident Jeremy Cushing described some cyclists as "lunatics" and claimed students were among the worst offenders.
And he claimed there is little attempt to enforce the law on cyclists using lights in Exeter.
He said: "I drive around Exeter several day a week, often between 4pm and 5pm. At this tome of year it means I drive in the dark.
"I am appalled by the number of cyclists who use the roads without lights. It seems that there is no fear of consequences, and indeed I am not aware that there is any effort to enforce the law."
He added: "For a motorist it’s terrifying: and if I run into one of these lunatics – who to make things worse normally seem to be wearing dark non-reflective clothing –no doubt it will be assumed that it is all my fault.
"I should say that the worst offenders are university students. I have to drive past the university regularly at around the end of the academic day and there are smarms of them. What is the university doing about this?”
It is illegal to ride a bike at night without lights and the laws are quite specific.
The Highway Code states: "At night your cycle must have white front and red rear lights lit. It must also be fitted with a red rear reflector, and amber pedal reflectors, if manufactured after October 1985."
A spokesman for CTC, the national cycling charity, said: "It is illegal to cycle on a public road after dark without lights and reflectors. Exactly which lights and reflectors, where to fit them and when to light up, is defined by the Road Vehicles Lighting Regulations (RVLR).
"It has to be said that the fine details of RVLR are seldom enforced, and provided you show some kind of white light in front and red behind, you are unlikely to be challenged.
"If you are involved in a night-time accident however, any slight illegality with respect to your lights or reflectors may be regarded as contributory negligence."