What is the significance of vulnerable road users (VRUs) in the context of highway safety?

1. VRUs are only a concern in developing countries
2. VRUs include pedestrians, cyclists, motorcyclists, and others with minimal crash protection, who are disproportionately represented in traffic fatalities and require targeted safety interventions
3. VRUs are vehicles that fail safety inspections
4. VRUs are roads that are vulnerable to flooding