Sarah Boyack says car dependency is causing problems

However, the executive insists it is not anti-car, just anti-congestion.

Ms Boyack said: "Traffic congestion is squeezing time out of our lives.

"Congestion is bad for our health, bad for business and adds stress and hassle to our busy lives.

"This campaign is simply about encouraging people to think about whether any of the journeys they make each week could be made easier by leaving the car behind.

"The campaign is based on careful research. Many of those surveyed indicated that they would consider choosing a different way of travelling into a town or city.

"That choice could be to take the bus, train, cycle or walk. The journey could be to work or to the shops, without all the cost and hassle of parking."

The minister added: "We want to move away from the old stigma of public transport being a last resort."

Scotland's leading bus and rail operators, who stand to benefit most, are contributing more than a quarter of the total cost of the campaign.

Sue Nicholson wants people to think before travelling

They have promised to back up their cash with a range of improvements to services and incentives to travel.

The move has also been welcomed by motoring groups.

"I hope it will make people think about their travelling habits," said Sue Nicholson of the RAC.

"What we are trying to advocate is that people use transport responsibly, that to use a pun, it's horses for courses, that they choose the form of transport which is most efficient and most beneficial and they think about it every time they make a travel choice."

But environmentalists have accused the executive of sending out a mixed message.

Friends of the Earth said the cost of the campaign is a fraction of the amount being used to build new roads in Scotland.

While it is quick to back any move to cut congestion, Friends of the Earth said it would take much more than a six-week advertising campaign to unclog our towns and cities.