John S.
Here's the chain of causation that leads to this situation.
1. California law stupidly says that if someone cuts into your lane right in front of you, and you hit him anywhere behind the lights, it's a "rear ender" and YOU are blamed.
2. A large number of skillful but stupid drivers take advantage of that law by performing a maneuver known as the "LA lane change": jam your front fender into a 2-3 foot gap between cars in an adjacent lane, then just follow it in, thus forcing the driver behind the gap to slam on his brakes and let you in.
3. Drivers who fall for the "LA lane change" get it done to them over and over again and become "rocks in the stream" of traffic, and are rightly regarded as complete idiots and buttholes by everyone else.
4. Naturally, all drivers with sufficient skill and brains start keeping up very closely, because it's the only way to prevent themselves from becoming part of that category.
Of course, this situation is marginally less safe than if everyone followed at a safe stopping distance. But the only step in the chain that can sensibly be changed is step 1. So long as that law stands, the possibility of these pileups must be regarded as one of the unavoidable risks of driving on the freeway.
