Halloween pop-up stores have been around since the 1980s, but took off during the recession because suddenly vendors had tons of newly available retail space.
Merging near the obstruction makes full use of all available road space, and can reduce unnecessary congestion by as much 40 percent, according to research from Minnesota.
The continent's storage facilities are already more than 90% full, and filling the last bits of available space is expensive, since the contents must be kept under high pressure.