While the percentage of travelers making online airline, rental car and hotel reservations has increased 15 percentage points during the past year, bookings for independent travel Web sites have increased by only 1 percentage point since 2007, according to the J.D. Power and Associates 2008 Independent Travel Web Site Satisfaction Study (SM).

The study, which is now in its fourth year, measures customer satisfaction with online booking for airline, hotel or rental car reservations made on seven major independent travel Web sites. Among the six factors that were measured during the study were competitiveness of price; ease of booking; usefulness of the information on the Web site and availability of booking options/travel packages.

The study finds that while 70 percent of travel reservations were booked online in 2008—up from 53 percent in 2007—only 16 percent were made through independent travel Web sites. Additionally, consumers who booked their travel using an independent Web site were considerably less satisfied compared with 2007, with satisfaction scores declining by 17 points on a 1,000-point scale to 785 in 2008.

For a third consecutive year, Hotwire.com ranks highest among independent travel Web sites, performing particularly well in competitiveness of pricing and ease of navigation. Priceline.com follows Hotwire.com in the ranking, also performing particularly well in competitiveness of pricing.

Additionally, the study finds that an independent Web site’s mix of travel services—how much of the site’s business is split between airline, rental car or hotel bookings—also impacts satisfaction scores.