Mr Dey told MSPs on Thursday that “demand management options including pricing and the cost of motoring” will be examined as part of what he described as a “world-leading” reduction.
A consultation on the “route map” to achieve it referred to UK research last year that showed “the public mood on road pricing has moved on since the 2000s” – when its consideration by Labour while in power at Westminster was shelved.
It said the Social Market Foundation study found: “In 2021, more people support than oppose road pricing as a concept, with a majority of people agreeing that road pricing would reduce congestion and pollution.”
The 12-week consultation also pointed to Scotland’s Climate Assembly, whose members were selected to be broadly representative of the population, reporting 63 per cent backed phasing in increased road taxes for cars to subsidise public transport.
Mr Dey said voluntary measures to reduce traffic would come first, such as encouraging people to switch to online options or more local destinations, cycle, walk, wheel or use public transport, or combine or share car journeys.
However, attempts by his predecessors to curb car use since devolution two decades ago have failed. Road traffic reached an an all-time high before the Covid pandemic, with total vehicle mileage approaching 30 billion a year.
Mr Dey said research would be commissioned to “explore equitable options for demand management to discourage car use, to enable the development of a new Framework for Car Demand Management by 2025”.
He said: “We know that we need to take bold action to tackle the climate emergency and this world-leading commitment makes the scale of our ambition clear.
“We cannot reach net-zero emissions through technological solutions alone, so we need individuals, communities and businesses in all parts of Scotland to look at their own habits and behaviours and think about how they could make changes.
"We don’t expect car use to drop at the same rate in urban and rural areas and the route map makes clear that there’s no one-size-fits-all approach.”
Mr Dey also acknowledged some groups would find cutting car use difficult.
He said: “The principle of a just transition is at the heart of our route map, supporting our work to tackle inequality and child poverty.
"We recognise that for some people reducing car use, especially in the short term, will be more challenging, including disabled people and their families.
"But we also need to recognise the unfairness of a status quo where the ‘car is king’ and where car use is made too easy.”
The minister said a range of initiatives that should reduce traffic were in the pipeline, such as free bus travel for under-22s from January 31, low-emission zones in city centres this year, and superfast broadband for the whole of Scotland.
Professor Iain Docherty, Dean of the Institute of Advanced Studies at the University of Stirling, and Scotland’s leading transport academic, said Mr Dey’s “openness to addressing who pays for transport and how, including consideration of different forms of road pricing, is very welcome”.
"Due to the embedded carbon in road vehicles and the manufacturing supply chain, even if we move as quickly as possible to a fleet of all electric and hydrogen vehicles, we’ll have to do with fewer of them in future,” he said.
"So achieving meaningful reduction in car use is essential for decarbonisation, but also has many more immediate benefits in terms of better air quality and making local neighbourhoods safer and more inclusive.”
But Neil Greig, the Scotland-based policy and research director of the IAM RoadSmart motoring group, said: “The majority of Scots struggle to own and run a car because it is the only viable option for them to get around and they will be hard pushed to recognise the picture painted by this document that car use is ‘too easy’.
"Potholes, congestion, parking zones, 20mph limits and record fuel prices should already be changing behaviour, but they are not.
"The Scottish Government has a mountain to climb to demonstrate that active travel and public transport are viable options for Scots trying to get to work, play and contribute to the economy.
"Cars in Scotland have never been cleaner, or our roads safer, and yet this document seems very light on new initiatives and additional funding that might actually change behaviour, as opposed to simply hoping people will get the message.
"We remain fundamentally opposed to any new and unfair Scotland-only road pricing schemes that don’t reduce motoring costs in other ways, such as tolls for busy roads, but lower fuel taxes.”
Steven Heddle, environment and economy spokesperson for the Convention of Scottish Local Authorities, with which the road map was devised since councils are responsible for most of the country’s roads, said: “Our current level of car use is unsustainable and incompatible with our climate targets.
The Orkney Islands councillor said: “The purpose of the route map is to help us find fair and sustainable ways to reduce car use wherever possible.”
Edinburgh City Council transport convener, Councillor Lesley Macinnes, said: ““None of us can afford to ignore the challenges in combating negative impacts of climate change and we must look to all sorts of solutions to meet those challenges.
"Our own City Mobility Plan, commits to a 30 per cent reduction in car kilometres – higher than the national goal – and our ambitious transport polices will move us in that direction. We need to be open to a number of radical measures which will help us to tackle the huge contribution that transport makes to health-related issues as well as air pollution and city congestion.”