Despite their low incomes, they have found no alternative to the extra burden of motoring costs to get to work or transport their children.
The study was done in Glasgow, but its authors said similar findings were likely in other Scottish cities.
The researchers said those forced to resort to car ownership were typically couples with young children living in deprived areas on the edge of cities with limited buses.
They would be seeking work or their jobs were likely to involve shift work or “gig economy”-type short-term contracts, such as in the retail and hotel sectors.
The research, published in the Transport Policy journal, stated: “A small but growing proportion of households (up to 8.5 per cent by 2011) are deemed ‘forced car owners’ by virtue of owning a car despite also reporting financial difficulties.
“Poor households are reluctant to relinquish their cars to ease money problems when under financial stress.
“For some, acquiring a car may be seen as necessary to better their circumstances.
“It is striking that in our analysis, those with financial difficulties are more likely to adopt a car than others.”
One of the authors, Dr Julie Clark, now a sociology and social policy lecturer at the University of the West of Scotland, said: “This challenges the assumption that the car is a sign of affluence, and that if you live in an urban area you can get about with no problem without one.”
Bruce Whyte, of the Glasgow Centre for Population Health, which helped fund the research, said: “The issue of ‘forced car ownership’ raises wider concerns.
“Long-term commuter trends reflect the rise of car dependency in Scotland.
“Car commuting has risen dramatically as bus use and walking to work has reduced equally dramatically.
“To reverse these trends will require greater investment in active sustainable modes of travel, in bus services in particular, but also train services and in more safe and attractive active travel routes to encourage more people to walk and cycle.”
Neil Greig, of the IAM RoadSmart motoring group, said: “This underlines the failure of long-term public transport policy to attract people out if their cars.
“If people need a car to get or keep a job then they will make sacrifices to do so.”
A spokeswoman for the Scottish Government’s Transport Scotland agency said: “We are investing over £1 billion annually in public transport and other sustainable transport options to encourage people out of their cars.
“The National Transport Strategy (NTS) refresh last year found households with higher incomes tend to have access to more cars or vans than those with lower incomes, which means that households with lower incomes are relatively more dependent on public transport and active travel.
“Changes in the cost of transport as they relate to accessibility and inequality will be further examined as part of the on-going review of the NTS.”