Terrorists have turned to vans and trucks to murder more than a hundred people across Western Europe in a matter of months, per Daily Mail.

Why it matters: "It is 'nigh on impossible' for security services to monitor and stop potential terrorists planning such murders and the only way to prevent them is by using barriers to protect pedestrians, according to one expert."

Barcelona latest — BBC: "Spanish police say they have shot dead five suspected terrorists in the town of Cambrils in a second vehicle attack, hours after another in Barcelona killed 14 people and injured dozens. Police said the men were linked to the Barcelona attack, which [ISIS] said it had carried out."

"Police are still hunting the man who drove his van into crowds on Las Ramblas in Barcelona on Thursday. Spanish media have named Moussa Oubakir, 18, as the suspect."