Two tidbits of news from AutoTrader.com — new research that shows car buyers spend 18 to 19 hours online before they make a purchase, and a record for unique users in January at AutoTrader.com.

The two news releases come on the eve of the opening of the National Auto Dealers Association convention, which starts tomorrow in San Francisco.

Research among more than 4,000 U.S. consumers showed that 60 percent of shopping time was spent online. Internet research was the most influential element in the search for a vehicle for 58 percent of used-vehicle buyers and 50 percent of new-vehicle buyers, the report said.

The research was conducted by Polk for AutoTrader.com. More details of the research are in this news release.

AutoTrader.com also said its traffic was up 9 percent in January over January 2009, with a total of 17.4 million unique users. That beat the previous monthly record of 16.8 million unique users in May 2010.

AutoTrader said 1.2 million unique users visited the service through its mobile services and 16.2 million visited on the website. “The numbers have been analyzed and scrubbed to remove visitors who accessed both the AutoTrader.com core site and the mobile platform for a true view of unique visitors,” the company said.