What is the purpose of rumble strips placed on the side of roadways?

Rumble strips are designed to create a physical and auditory alert for drivers who may be drifting off the roadway. When a vehicle runs over these strips, the vibration and noise serve as a warning to the driver, prompting them to take corrective action and steer back onto the roadway. This feature is particularly important for preventing accidents due to unintentional veering off the road, especially in areas where there may be a higher risk of run-off-road crashes.

While signaling the end of a construction zone or indicating a speed limit change serves specific traffic management purposes, it does not address the primary safety function of rumble strips. Additionally, while rumble strips can aid in guiding drivers back onto the road indirectly by alerting them to their position, their primary design is to act as a warning system for drivers as they approach the edge of the roadway. Thus, the correct answer highlights the primary safety objective of rumble strips.