From what I've heard from other bikers interviewed on the news, they deliberately slow cars and attempt to stop traffic so that the other riders have a clear road to perform their illegal stunts. That's why they were attempting to take over all lanes of the highway.
Interesting that these other bikers say "they were attempting to take over all lanes of the highway" in order "that the other riders have a clear road to perform their illegal stunts" as though that was the bike gang's right.
Strangely, when I look at the video of these guys, they look like they are participating in the staging of an automobile accident. The Coalition Against Insurance Fraud calls this piece of choreography the Swoop and Squat. In their description, CAIF says "a suspect vehicle suddenly swoops in front of you and jams on the brakes, causing a rear-end collision." They go on to say that swoop driver, and passengers if any, "then make large collision and injury claims against your auto policy, for example."
http://www.insurancefraud.org/scam-alerts-staged-crash.htm#.UlEGQ-DPbtU
DMV.org elaborates that, as the S&S is in progress, "another vehicle will simultaneously pull up alongside your car, preventing you from a preventive swerve." Among their many tips, DMV suggests taking photos of all involved vehicles from many angles, "capture on camera the license plate"--interesting that, as other posters have already noted, many bikes had NO license plates.
http://www.dmv.org/insurance/how-to-handle-staged-car-accidents.php
Aol.autos posted a very informative article, with video, on Aug. 29, 2013. The video "shows some telltale signs that you might be the victim of a staged crash". The article states that "The National Insurance Crime Bureau said questionable claims were up 46%." The video says professional S&S drivers and their accomplices stage the crashes to make it look like the innocent driver was at fault, and they pick as their victims cars that look like the drivers would have insurance. The financial damage of these crashes is considerable. FBI statistics say staged accidents cost insurance companies about $20 billion per year. If that isn't bad enough, the article reveals that between 2007 and 2008 there were 71,452 fatalities as a result of automobile collisions. That is a frightening statistic, because if even just 2% of these crashes were the result of staged collisions, then 1,430 people died because of someone else's greed.
http://autos.aol.com/article/car-insurance-staged-accidents/
Wikipedia also had some intriguing details. The article about Staged Crashes notes that in 2011, "a group of seven people in North and South Carolina were arrested for allegedly stealing over $100,000 through staged crash schemes." The article also notes that the swoop care "is usually driven by an experienced ring member" because being a swoop driver is dangerous, sometimes fatal.
Staged crash - Wikipedia, the free encyclopedia It appears to be dangerous not only for the swoop driver, but for the accomplices as well. IMO things can go wrong even in a choreographed routine. When you're playing games with vehicles, IMO, people can get badly hurt. My guess is that, to be better prepared, the swoop driver would have to get in some practice on the actual streets he planned to S&S on. Preferably with his/her cronies. JMO.
The video of the NY melee, and related witness statement and photographs which were released show some classic S&S techniques, including a swoop vehicle, accomplice vehicles and people preventing the targeted driver from using defensive driving techniques to protect himself, his family, and other drivers on the road. As well, images show outright intimidation of the SUV driver. (Just why did those nice friendly bikers begin slicing the SUV's tires BEFORE he saved his family by driving away?) Instead of the swoop driver being injured, it was one of his cohorts. And that's a tragedy.
This staged crash thing, IMO, is its own industry. I hope that LE on many levels will have covert operatives investigating people (even people like FedEx drivers, plumbers, military reservists, musicians, off duty cops and corrections officers) who become involved with practicing S&S patterns on public thoroughfares. I further hope that LE and law makers will take a hard look at agents provocateur, like the swoop drivers, and increase the penalties for their reckless disregard for human life. When a man brakes short in order to prevent injuries to another person, it's a far different situation than when a man brakes short in order to defraud insurance companies or to keep a highway completely clear so his friends can pretend to be Hollywood Stunt Drivers. Someone should explain in exquisite detail the safety precautions that are in place to protect the drivers and actors and crew when tv and movie stunts are filmed. Movies are not real life. In real life, when you set up a stunt without precautions, someone can be maimed. Someone could be killed. And there might be no financial support to cover the costs of treatment and subsequent rehabilitation, or to cover funeral expenses, or support surviving family members. Movies are expensive in part because of the insurance they have to carry. In real life, sometimes the people who get hurt have no insurance to cover their expenses. JMO, but someone who thinks it's cool to perform stunts without safety precautions, without permits, is responsible for the outcome of those stunts in every way--including financially. I don't know if there are laws on the books to force the swoop driver to accept the burden of paying the injured man's expenses for the rest of his life, but I hope there is some equivalent.
Good luck with that Gloria. 
