Figures uncovered by the Liberal Democrats in Parliament show that over the past decade, the number of vehicles on roads in the old county of Avon have increased by 15%.
It means that congestion on local roads has gone up since Labour came to power in 1997, despite promises to reduce the number of people relying on cars to get about.
"When Labour came to power in 1997, John Prescott, who was then deputy Prime Minister, said, 'I will have failed if in five years' time there are not many more people using public transport and far fewer journeys by car. It's a tall order but I urge you to hold me to it.'
"The rise in traffic in Bristol and across England generally is clearly a huge failure by the Government who promised so much but have delivered more congestion, pollution and more expensive buses and trains.
"The Government needs to look seriously at how to provide better buses and trains at an affordable price before Bristol grinds to a halt.
"A Transport Bill is now being debated by Parliament and there are a number of plans in it that will give powers to councils to improve bus services. This is a welcome move but it is a pity that Labour have taken over a decade to get this far.
"Yet even now there is a danger that the powers to improve bus services will be watered down by the Government. Liberal Democrats will be pressing the Government hard to make sure this doesn't happen."