The number of test drives has halved in the last 12 months.
Research by Google also shows that the number of new car buyers visiting just one dealership before making a purchase has doubled to 32% in the same period.
Adrian Joseph, director – automotive at Google, said: “We are arguably in the midst of the biggest change in recent times within the automotive industry – a change driven by significant shifts in consumer behaviour enabled by technology and, in particular, the internet.”
He added: “The influence of some traditional media is falling dramatically. In short, the car-buying process is being turned on its head.
“This toxic situation has serious implications for dealerships, and understanding the online opportunity to affect consumer choice has never been more critical.”