Public transport is failing to entice commuters as it emerged just 6% of people use services to travel to work in the South West.
Figures showed around three quarters of people in the Westcountry reach their place of employment by car – above the national average of 67.7%.
Less than 4% of people in Cornwall use public transport while 6% do so in Devon.
The figures come as the price of petrol remains above £1.30 per litre and the price of diesel around £1.35 per litre – both almost double their cost ten years ago.
John Philips, South West secretary for the GMB who published the figures from the 2011 Census, said:
"These figures demonstrate why the massive hike in the price of fuel has hit this region very hard.
"The cost of putting fuel in the tank and paying fares to get to work is an essential and unavoidable item in the household budgets of nearly three quarters of the workers in this region who travel to work.
"The low numbers using public transport outside the main cities is a reflection on the sheer lack of availability giving people no alternative to using their car.
"The figures also demonstrate the importance of the local economy where people can walk to work."
Mr Philips made the statement as the GMB holds its annual congress in Plymouth from yesterday until Thursday.
Less than one fifth of people walk to work in Devon (16.9%) or Cornwall (15.3%). Just 1.8% of people cycle to work in the Duchy while the figure stands at 2.9% across the border.
Across the wider South West including Gloucestershire, 74% of the workforce travel to work as driver or passenger of a private vehicle.
Less than one fifth (18.4%) of people in the wider region get to work by either cycling (14.6%) or on foot (3.8%).