Story highlights More than 120 people have been killed in vehicle ramming attacks in the West since 2014, including Thursday's in Barcelona, writes Peter Bergen

Terrorist groups have favored these low-tech attacks since they require no training or expertise, Bergen writes

Peter Bergen is CNN's national security analyst, a vice president at New America and a professor of practice at Arizona State University. He is the author of "United States of Jihad: Investigating America's Homegrown Terrorists."

(CNN) The attack on one of Barcelona's historic streets Thursday is the latest in a series of vehicle ramming incidents in the West that have killed 129 people since 2014.

At least 14 people were killed and 80 injured when a van, which witnesses said was traveling at a high speed through the tourist area, mowed down people in Barcelona.

Since 2014 there have been 14 vehicle ramming attacks in the West, according to a count by New America, a nonpartisan think tank.

Like school shooters, terrorists learn from other attacks. Vehicle attacks have become a method of choice for terrorists in the past three years since they require no training or expertise and they inflict just as much terror as more conventional tactics such as bombings.

Three years ago, Abu Muhammad al-Adnani, ISIS' spokesman, called for attacks in the West using vehicles as weapons.

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