“Infomediary” auto resource sites -- such as Edmunds.com and Kelley Blue Book’s KBB.com -- get 77% of automotive web site traffic. But they are ineffective in driving traffic to buying sites or OEM sites.

That’s according to a new study by Jupiter Media Metrix, a research firm that tracks Internet trends and profitability.

The study, released today, says:

* “Infomediary” sites, while the most popular with consumers, only drive 18% of their traffic to buying services and OEM sites. Instead they usually drive most of their traffic back to major web portals.

* Major web portals such as Yahoo!, AOL and MSN – where consumers often begin their browsing sessions -- are the largest single source of traffic directed to the top OEM sites and buying service sites. OEM sites receive 36% of their traffic from portals and buying services sites receive 47%.

Jupiter analysts say OEMs should leverage the Internet to drive offline automobile purchases because consumers are still uncomfortable making such expensive purchases online.

However automotive web sites are still unequipped to provide that kind of information, say the analysts.

Only 30% of automotive sites allow customers to access inventory information at a particular dealer, according to a Jupiter.

The study concludes that consumers visit automotive sites for specific purposes during the buying process, but no single player currently satisfies all functional needs.

“The recent demise of several pure-play Internet buying services highlights the continued near-term supremacy of the off-line dealer in the automotive buying process,” says the study by analysts Eric Horowitz, Jenna Pelaez and Fiona Swerdlow.

They add, “While OEMs, dealers and online buying and information services all strive to connect consumers to cars, consumers are confounded by an abundance of online offerings often providing confusing information due to incomplete integration between online and offline channels.

“Consequently, consumers continue to visit multiple automotive sites for distinct purposes during the automotive buying process, limiting the seamless conversion of online shoppers into offline buyers.”