As noted above a bike helmet doesn't cut it. It's usually the type of helmet you would be allowed to wear on a motorcycle although it would be one that doesn't have a face shield as you are behind a windshield.
2014 EBII 435i xDrive M-sport
Gone: 2011 TiAg F25 X3 xDrive35i M-sport
Gone: 2008 TiAg w/Coral Red E88 135i Cab M-sport