Almost half (45%) of drivers convicted of hit and run offences claim they would not have left the scene if they had known it was against the law, according to new research.
A survey also found that motorists aged 16-34 are most likely (33%) to have failed to stop after a crash because they are scared of the consequences.
The most common reason (31%) for older drivers committing the same offence is that they did not think the incident was serious enough.
Some 695 people convicted of carrying out a hit and run were polled for the study, which was conducted by the University of Leicester.
Dr Matt Hopkins, a senior lecturer at the university, said: "For a number of drivers there is clearly confusion about the legal requirement to report an accident.
"Importantly, some differences are observed between younger and older drivers that could be developed into preventative strategies."
Ashton West, chief executive of the Motor Insurers' Bureau (MIB), which commissioned the research, said: "There is a real need to understand why there are so many hit and run accidents.
"The completion of this independent research will provide useful insights which we will share with the Government, police, the insurance industry and other interested bodies so that we can take action to tackle this problem together."
Under the Road Traffic Act 1988 a driver involved in an accident must stop and give their name and address to any other person involved.
The incident must be reported to the police "as soon as is reasonably practicable" if someone is injured or if personal details are not exchanged.
Failure to do so is punishable by a maximum sentence of six months' imprisonment.