Rumble strips are grooved or raised patterns on road surfaces that create noise and vibration when vehicles drive over them, alerting drivers who may be drowsy, distracted, or drifting from their lane. Shoulder rumble strips along road edges warn drivers leaving the travel lane. Centreline rumble strips prevent head-on collisions from crossing the centre line. Transverse rumble strips across lanes alert drivers approaching intersections, toll plazas, or work zones. Rumble strips are low-cost safety improvements that significantly reduce run-off-road and head-on collisions. Provincial highways commonly use rumble strips; municipalities may install them on appropriate roads. Design considers noise impact on nearby residents.