
The site, which reaches more than 10 million motorists every month, is being revamped to include high-impact homepage takeovers, rich media and Flash display creative, sold by Aegis's digital agency Diffiniti.
In addition, AutoTrader will continue with its brand icon Autobot to profile the site on some of the busiest websites in the UK, including Sky, MSN, Facebook and AOL.
Media planning and buying has been undertaken by MediaCom, with creative by Hurrell Moseley Dawson & Grimmer, and the drive will feature ads across TV, radio and online, continuing the theme of "The World of Cars Made Easy" and featuring the "Land" and "Underwater" creative.
Matt Thompson, marketing director at AutoTrader.co.uk, said the heavy investment was to stimulate demand for new and used cars for dealers.