Fortifications are not the only form of defences. In some scenarios the defender may place obstacles. Obstacles are a hindrance to enemy movement and are split into two categories: razorwire and tank traps.
Razorwire. If the defender has suitable models then he may set up razorwire. Razorwire comes in 6" long sections. If the defender has obstacles then he gets 1D3+3 sections of razorwire to deploy at the start of the game.
Razorwire counts as difficult ground for all infantry, cavalry and bikes. Vehicles can drive over razorwire with no effect. Skimmers and jetbikes are not affected by razorwire, neither are jump pack troops.
Tank Traps. Tank traps also come in 6" long sections. If the defender has obstacles then he gets 1D3+3 sections of tank traps to position at the start of the game.
All vehicles, except skimmers, treat tank traps as impassable ground. Tank traps do not affect infantry movement, they can simply run around or clamber over them. Tank traps will provide cover for infantry.
Tank traps may be destroyed by enemy fire. They have an Armour Value of 10, and any penetrating hit destroys the section automatically. Glancing hits have no effect. They may be assaulted by infantry as if they were a stationary vehicle.