Not only should all motorists be more cognizant of riders but us two-wheelers need to put forth an equal amount of effort making sure we're seen.
Drivers need to check their mirrors before changing lanes in addition to looking over their shoulders, seems people forget about that last step these days.
Riders also shouldn't lane split to quickly and another tidbit that many riders don't know is that if you're splitting 15 mph over what the speed of traffic is doing you could get a reckless driving ticket (In CA that is). It's not a given but it's a trend that's starting to happen.
Here's a short article about sharing the road: