Rumble strips in the center of two-lane rural roads and on the shoulder of motorways are a countermeasure aimed to help drivers who unintentionally are about to leave the lane, for example, due to fatigue or inattention. Rumble strips are widely used. They are installed in the raised profile or as in-ground (milled or pressed). The design varies in width, depth, length, and design. The most effective are the in-ground ones. Evaluations show an effect of 10% reduction of all injury crashes and 37% reduction on target crashes (head-on, single crashes to the left, etc.). Rumble strips contribute to speed reduction of 2–5 km/h and an increased distance to them with 10–15 cm, something that is good for vehicle-to-vehicle interactions, but less good for pedestrians and cyclist using the shoulder. To summarize, rumble strips save lives to a rather small cost in relation to other infrastructure-based countermeasures.