BMW led the manufacturer website league back in January 2008, but Volvo’s website went into first place after receiving an overhaul.
BMW is now joint second with VW. Mercedes-Benz has moved up from sixth place to join Audi in joint fourth. Honda had a surprising result, moving from fifth to seventh.
Global Reviews' 'Comparing the Car Sites' benchmark measures customers' experiences across nine car websites. The sites were assessed against more than 500 objective criteria including the information available to prospective buyers, customer support, service offered to vehicle owners, and general site usability.
The study found Mercedes and VW offer the best site navigation with scores of 82%. Honda scored 63%.
VW offer the best experience for prospective buyers with a score of 72% for this category. Porsche scored 53%. Volvo offers the best customer support online with a score of 70%. Lexus scored 39%.
Content and tools and the information and support given to vehicle owners are the areas where most sites could be improved.
Volvo leads the field again with a score of 62% for content and tools, and 43% for vehicle owner support. The industry average was just 40% and 30% respectively for these categories.
The study also found that users want access to comparison tools and car wizards to help them find the information they are looking for.
Adam Goodvach, Global Reviews director, said: "The vast majority of consumers depend on websites to research their options when buying a car.
"Car companies are missing a trick if they do not provide their customers with the best possible online experience."