“As the recent terrorist attacks in Barcelona and Cambrils Spain attest, using vehicles as a readily available means to mow down pedestrians is a growing trend. And it is a frightening one. It involves turning an easily-acquired vehicle into a weapon to kill or maim in places where citizens presume they are safe. No firearms have to be acquired or bombs made. That is no doubt why vehicle rammings, along with knife assaults, are being advocated by jihadist organizations like ISIS and al Qaeda. Attacks can be done quickly and with little preparation, which decreases the possibility of discovery and intervention by security authorities before the attack. Since January 2015, there have been ten such vehicular assaults. Prior to the attacks in Spain, similar assaults occurred in France, Germany, Sweden, Austria, Belgium, Israel, the Palestinian territories, the United Kingdom, and the United States. This type of vehicular assaults can occur at public surface transportation locations such as bus stops or train stations. However, the data suggests that, so far, vehicle rammings are not as lethal as might be thought, and have not been used as often as one might expect against public transportation targets. This possibly could be because major train and bus terminals, and even bus stops in countries that have experienced these attacks, can be protected by bollards and additional police or military presence.”

Source and further reading: http://transweb.sjsu.edu/PDFs/research/terrorist-vehicle-attacks-on-public-surface-transportation-targets.pdf?platform=hootsuite