ATLANTA — The Internet is, by far, the most influential media channel for car shoppers, according to a new Polk study commissioned by AutoTrader.com.

The 2013 Polk Automotive Buyer Influence study found that while the amount of time consumers spend shopping for a car has decreased dramatically in the last two years, the percentage of shopping time spent online has increased substantially.

First conducted in 2011 and then fielded again in 2013, the study showed that new-car buyers who used the Internet in the shopping process reported spending 13.75 hours shopping for a vehicle, a decrease of 5.25 hours since 2011. Similarly, used-car buyers who used the Internet during the shopping process spent 15.25 hours shopping, a decrease of 2.75 hours since 2011.

Although consumers are spending less time shopping overall, they are spending a greater percentage of their shopping time online than they were in 2011. Previously, buyers spent an average of 60 percent of their shopping time online, but that percentage increased to 75 percent in 2013 (77 percent for new-car buyers and 73 percent for used-car buyers). These changes were likely driven by several factors, including the improved quality and quantity of listings, as well as better merchandising online, greater use of mobile devices and also macro factors such as the continually improving economy.

“The content that is offered to consumers via Internet is continuing to improve,” explained Isabelle Helms, senior director of research and marketing analytics at AutoTrader.com. “Dealers are becoming a lot savvier about how they should effectively promote their listings and advertise on third-party shopping sites. That is certainly one huge reason why the internet has become more efficient.

“I would also say that more and more consumers are becoming aware that these sources exist and that they should be leveraged during the shopping process.”

The study also revealed that the role of traditional media in the shopping process has decreased notably. Though all forms of traditional media showed decreases in usage, the biggest declines in usage of traditional media during the shopping process for car buyers were seen in print newspapers, television and direct mail.

For new-car buyers, use of television ads during the shipping process showed the biggest decline, dropping from 34 percent in 2011 to 22 percent in 2013. Close behind was print newspaper, which dropped from 28 percent in 2011 to 18 percent in 2013. Direct mail also dropped from 16 percent in 2011 to 8 percent in 2013. For used-car buyers, use of television also exhibited the biggest decline, though the decrease was slightly less pronounced.

Among Internet users, 62 percent of used-car buyers and 47 percent of new-car buyers indicated that the Internet was the primary source that led them to the dealership where they bought a car, which was fifteen times higher that of any other media source cited in the study.

“While dealers, OEMs and their advertising agencies have shifted more money into online advertising, there is still a large imbalance in the allocation between traditional and digital mediums,” said Kevin Filan, vice president of customer marketing and industry relations at AutoTrader Group. “We know from the study that buyers who use the Internet are spending the most time on third-party sites, so dealers and automakers should ensure they are marketing their brands, their dealerships and their inventory where the active car shoppers are going online.”