There are many ways to make Caltrops, like this or use chain-link fencing, or just long nails bent around each other.etc.
Drop across a motorway in loads approximately 500 metres apart to create large-scale, and long-lasting traffic jams.
Ideal for blocking transport vehicles from entering or leaving distribution centers, warehouses, and other storage or manufacturing facilities. Can also be used to block traffic on important access roads to Industrial Zones, like Ring Road..