Vehicle fuel economy is the determining factor when consumers go to purchase a car, according to a report by the University of Michigan's Transportation Research Institute.

The study analyzed the importance of fuel economy through an online survey. Of the 674 respondents, 98 percent reported that fuel economy was important to some degree when making vehicle purchasing decisions and 49 percent rated it as "very important." 

The report compiled by the institute's Michael Sivak and Brandon Schoettle also found that 52 percent of respondents do not care how a vehicle is able to achieve fuel savings and reduce emissions.

Respondents preferred gasoline-hybrid technology over all others at both lower ($2.50 per gallon) and higher ($5 per gallon) gas prices. Continuously variable transmissions and cylinder deactivation were the second and third highest rated (although in reverse order at the higher gasoline price).

The willingness to pay for improved fuel economy was clearly associated to the degree of improvement. About 90 percent of respondents would pay $1,000 for a 5 percent improvement, while 75 percent would pay for a 10 percent improvement and 50 percent (median) for a 25 percent improvement.

The report gathered its findings from "Motorists' Views of Fuel Economy and Advanced Vehicle Technologies," which was conducted in April. Read more about the study here.