More than one in 10 women say they avoid driving on motorways due to nerves, according to a new study.
Almost half of all motorists know someone who refuses motorway driving, the survey of more than 29,000 drivers found.
The research said one in four drivers was even nervous when they know a friend or relative was making a journey on a motorway.
The AA Charitable Trust, which commissioned the study, also found that one in 50 people using the AA's online journey planner chose routes that avoid motorways.
Latest government figures suggest that motorways in Britain are actually safer than other types of road, as they accounted for 5.4% of all fatalities last year despite carrying around 21% of traffic.
Some 2,000 free two-hour Drive Motorway courses are being made available by the AA Charitable Trust to help motorists overcome their fears.
The charity's director Edmund King warned that a growing number of drivers did not understand the new smart motorways, where the hard shoulder is used as a running lane to increase capacity.
"One of our concerns has been the lack of lay-bys on stretches of smart motorway where the hard shoulder has been removed," he said.
"The current rules state you only need lay-bys every 2.5km (1.6 miles), whereas we would like to see twice as many.
"The hard shoulder can also be a very dangerous place but it is not as dangerous as breaking down in a lane of live traffic. If you do get stuck in a live lane the advice is to ring 999.
"Drive Motorway will give comprehensive advice on what drivers should do if they breakdown on such a stretch of motorway and will help alleviate fears about motorway driving."