NYC truck attack: How terrorism has become simpler, more independent since 9/11

— -- The deadly truck attack in New York City Tuesday was the latest example of an evolution in the terrorist threat that values simplicity and low-tech weapons over the higher-profile attacks of the past, like the ones on Sept. 11, 2001, experts said.

"Today we face a very different terrorism threat than we did even five years ago," said John Cohen, an ABC News consultant and a former counterterrorism coordinator for the Department of Homeland Security.

"What we've seen instead of carrying out complicated attacks that result in thousands of deaths like the one we saw on 9/11. We're seeing increasingly these incidents targeting places called soft targets, which are places that are open to the public that are difficult to secure, and using weapons in the attack that are easily obtained, such as cars, trucks, knives and guns," he told ABC News.

Suspected terrorist Sayfullo Saipov, 29, came to United States from Uzbekistan in 2010 and lived here for seven years before plowing into people on a pedestrian and bicycle path in lower Manhattan on Halloween afternoon.

Eight people were killed in the attack, and more than a dozen others were injured.

He passed a background check when he started work as an Uber driver, the company said in a statement after the attack, and he held business licenses for two Ohio-based trucking companies that date back to when he lived in that state, before moving to Florida and later New Jersey, where he, his wife and three children were based at the time of the attack.

Investigators searching Saipov's online activities have found social media links to people who are or were subjects of terrorism-related investigations.

But the portrait that has emerged so far is of someone who found ISIS propaganda online, with no indication of his being part of a cell or in any way being directed to do what he allegedly did Tuesday.

New York Gov. Andrew Cuomo echoed that idea, telling CNN this morning that Saipov was a "lone wolf."

"There's an evolution of tactics for the jihads, right? It's no longer about the training camps in a geographic area. They now have a platform with the internet, and you can download material, and they have a simple template: Rent a car or truck, create mayhem," Cuomo said.

"He was associated with ISIS, and he was radicalized domestically," Cuomo said.

That changing tactic also means that trucks and vans — which were once seen as modes of transportation used to carry terrorists' weapons, like the truck bomb used in the 1993 World Trade Center bombing or the 1995 Oklahoma City bombing — are now being used as weapons themselves.

Cohen said the shift happened "in earnest in 2014."

"Al-Qaeda was emulating what ISIS was doing, which was, in addition to urging people [initially] to travel and come to them to be radicalized, they began urging people to stay at home and act independently,” Cohen said.

He added, “In doing that, they knew they couldn't train people to do complicated things like build bombs, so they urged them to use these obtainable items as the weapons and to target places that would be easy to attack.”

ABC News' Brian Ross, Aaron Katersky, Josh Margolin and Dylan Goetz contributed to this report.