Bollards are designed to stop vehicles from entering restricted or sensitive areas, providing a high level of security against vehicular threats. They are often used at the perimeter of sensitive buildings to prevent potential attacks from vehicles. Fencing can deter or delay intruders but is less effective at stopping vehicles. Access control vestibules are more about managing individual access and less about vehicular threats. Security guards can be effective but may not be able to physically stop a vehicle without additional barriers like bollards.