Which of the following is an example of a systemic approach to road safety, as opposed to a hot-spot (reactive) approach?

1. Installing a traffic signal at an intersection that has experienced 15 crashes in the past year
2. Adding rumble strips along all two-lane rural highways based on crash type and risk factor analysis
3. Conducting a road safety audit at a specific high-crash intersection
4. Responding to citizen complaints about a dangerous curve