It’s 6:55 Saturday morning, and entire neighborhoods along a 10-mile stretch of secondary roads are vibrating as two heavy-duty dump trucks pass with engines growling. Few people are awake at this hour except for those heading to the gym, getting ready for work, or the lone homeowner eagerly awaiting the delivery of building materials from a landscaping supplier. The convoy’s lead driver is using a smart phone with GPS to find the delivery site — a modest three-bedroom, two-bath home undergoing renovation in suburbia. The homeowner flags him down in the street and the pair discuss a suitable drop zone. Meanwhile, the second driver waits a few doors down with the motor running until the first truck unloads its cargo.