A video put together by Dan Guitierrez and Brian DeSousa of Dual Chase Productions demonstrates the safest way for cyclists to ride in Mandeville Canyon. The video emphasizes that despite popular opinion, riding to the right isn't always the safest or most courteous way to bike. For example, on a downhill, where a cyclist will easily be able to go the speed limit. Such a maneuver provides no safe maneuverability for either driver or cyclist should a car come out of a driveway into the cyclist's path or a car come around a blind curve at the automobile.
The video also advises cyclists to "take the lane" when they feel it appropriate. Far from being a "rude" gesture to drivers, it is often the safest thing a cyclist can do for parties. While the video doesn't address the etiquette and legality of two cyclists riding next to each other; there is no law against such an action and one can extrapolate from the video that there are times when it is both safe and smart to do so.
Lest anyone think this video was created just to support the two injured cyclists or to score political points; the suggestions mirror those put out in a more generic video done by Guitierrez and DeSousa that was released months ago.