Why are there metal containers on highways?

Crash cushion barriers, also known as crash attenuators or impact attenuators, are safety devices designed to reduce the severity of collisions. They are typically installed in areas where vehicles might accidentally veer off the road or need to be redirected. Here's a detailed look at crash cushion barriers and their uses:

- Purpose and Function: Crash cushion barriers are designed to absorb the energy of a collision, thereby reducing the impact force experienced by the vehicle and its occupants. This energy absorption helps to prevent severe injuries and fatalities. The barriers also help to redirect the vehicle away from hazardous areas, minimizing the potential for secondary accidents.

- Types of Crash Cushion Barriers:

  - Sacrificial Systems: These barriers are designed to deform or collapse upon impact, absorbing the energy and slowing down the vehicle gradually. Examples include sand-filled barrels and water-filled barriers.

  - Reusable Systems: These barriers can return to their original shape after an impact and can be used multiple times without replacement. Examples include spring-based or hydraulic-based systems.

- Common Applications:

  - Highways and Freeways: Installed at the ends of guardrails, bridge abutments, and other fixed objects to protect vehicles from direct collisions.

  - Construction Zones: Used to protect both workers and drivers by providing a barrier between the work area and traffic.

  - Intersections and Toll Booths: Placed at locations where vehicles may need to come to an abrupt stop or where there is a high likelihood of collisions.

  - Roadside Hazards: Installed near fixed objects such as poles, signs, or trees that are too close to the road and pose a collision risk.

- Design and Materials: Crash cushion barriers are made from various materials, including steel, plastic, and concrete, depending on the intended application and level of impact resistance required. The design often includes a series of interconnected modules that compress upon impact, dissipating the energy.

- Benefits:

  - Enhanced Safety: Significantly reduces the risk of fatal and severe injuries during a collision.

  - Vehicle Redirection: Helps to steer vehicles away from hazardous areas, reducing the risk of secondary accidents.

  - Protection of Infrastructure: Prevents damage to road infrastructure, such as bridge supports and signposts, which can be costly to repair.

  - Minimizing Traffic Disruptions: By containing and managing the impact, these barriers help to prevent accidents from causing major traffic disruptions.

In summary, crash cushion barriers play a critical role in road safety by absorbing collision energy, protecting vehicle occupants, and preventing damage to infrastructure. Their use in various high-risk areas helps to mitigate the impact of accidents, enhancing overall road safety.