Although ubiquitous now, aero road helmets are a relatively new development. Giro made waves when it launched the Air Attack in the summer of 2012; some loved it, many hated it, but all cycling fans certainly noticed the distinct, rounded shape. Now, at the 2014 Tour de France, the vast majority of teams have helmet sponsors with aero options of some sort.
As with road bikes, the cycling industry is rotating through the process of differentiating new categories and then blurring the lines between them. There are a few clear out-and-out aero road helmets at the Tour like the Air Attack, the POC Octal Aero and the Scott Vanish Aero, which have