common bridge guardrail types:
1. W-Beam Guardrail a standard highway guardrail with a w-shaped profile;
2. Cable Barrier a flexible system of cables suspended between posts;
3. Beam Barrier a pre-fabricated beam that can be installed quickly;
4. Thrie Beam Guardrail three corrugations in a w-beam pattern for extra strength;
5. Post Block System posts and blocks used to mount guardrails;
6. Steel Railing steel railing designed to deter vehicles from running off the road;
7. Crash Cushion