Truck drivers were easy kidnapping targets because their fixed routes lacked protection.

Evidence

In particular, truck drivers who navigate public roads based on set routes that make them easy to follow and intercept with little protection or security. Pakistani workers, a prominent part of this workforce, were some of the first people abducted when convoys delivering goods, products, and equipment required by the American military were attacked. — Junaid Rana, Terrifying Muslims, 17