As many as 29% of drivers aged 18-30 said they were unprepared to drive alone when they passed their test, the survey by Co-operative Insurance found.
Also, 24% said an accident they had could have been prevented if they had spent more time learning to drive, with 62% in favour of a minimum learning period being introduced.
Based on responses from 2,000 drivers aged 18-30, the poll also showed that 21% avoided motorways after passing their test, while 14% considered themselves to be "'unprepared" to drive at all.
In addition, 29% felt they were not ready for night driving, 21% considered driving lessons did not prepare them to drive with passengers, 19% avoided city centres, 14% could not face driving in the rain and 8% avoided right turns.
A total of 18% passed their driving test after spending three months or less learning to drive and 50% took six months or less to pass.
James Hillon, director of general insurance at Co-operative Insurance, said: "A lot of public debate is taking place on how safety can be improved and insurance premiums cut for young drivers, but the views of young motorists themselves are rarely heard.
He went on: "Young people say that the current system fails to prepare them for driving on motorways, on their own or in poor conditions. They want to see a more comprehensive approach and are hugely in favour of a minimum learning period for all new drivers to fully prepare them and we fully support this.
"It's startling that one in four young drivers who have had an accident believe it could have been prevented if they had taken more time to learn to drive before taking their test."
Roads Minister Stephen Hammond said: "Improving young drivers' safety is a priority for the Government. That is why we have already improved the driving test so that it better reflects real-life conditions on the road, rather than focusing on specific manoeuvres.
"We are also considering a range of options to ensure learners and newly-qualified drivers are properly prepared for the road and we will publish our proposals later in the year."
AA president Edmund King said: "It is worrying that so many young drivers feel the driving test does not prepare them adequately for elements of life on the road.
"Changing the driving test alone isn't enough to cut young driver deaths. Road safety education needs to be a compulsory part of the national curriculum so that by the time someone is old enough to apply for their provisional licence, they already have a solid grounding in road safety and a sensible attitude towards driving.
"We also believe there are ways that safety could be improved by making changes to the way people learn to drive and we are interested to see what proposals the Government puts forward in its green paper on young driver safety due out this autumn.
"We would support the idea of allowing learner drivers on to motorways with a trained driving instructor and also a minimum learning period, if it was enforced by a logbook to ensure the learners had covered a wide-ranging syllabus before taking their test."