Chapter 4 of 518% of exam
Speed & Conditions
Posted limits assume good conditions, and Massachusetts expects you to slow down when the road or weather is poor. Choosing a safe speed is one of a driver's most important decisions.
Default limits
Unless otherwise posted, a thickly settled or business district is commonly 30 mph and a school zone is commonly 20 mph. Always obey posted signs, which set the legal maximum.
Reasonable and proper speed
Even below the posted limit, you must drive at a speed that is reasonable and proper for traffic, road, and weather. Heavy traffic or poor visibility calls for a slower speed.
Adjusting to conditions
In rain, snow, or fog, reduce speed and increase your following distance because traction and visibility drop. Brake gently and steer smoothly on slick surfaces.