Not sure if this is the same ad being filmed or not, but if so it was on the Mulholland Hwy in Southern California, near Malibu.


Youtube Link

Edit: My girlfriend, who grew up around there, says that road is usually choked with traffic during the week, and apparently is a very popular place to ride the "twisties" for motorcyclists. Probably not the best touring road, unfortunately. Looks great when they block off traffic to film car commercials though.