Assured Clear Distance Ahead
Faster drivers must yield to slower and stopped traffic ahead. All vehicle operators must travel no faster than is safe and will allow them to stop within their sight distance. This legal principle is known as assured clear distance ahead.
“The Assured Clear Distance Ahead (ACDA) is the distance ahead of a vehicle or craft which can be seen to be clear of hazards by the driver, within which they should be able to bring the vehicle to a halt. It is one of the most fundamental principles governing ordinary care and the duty of care and is frequently used to determine if a driver is in proper control and is a nearly universally implicit consideration in vehicular accident liability.”
The North Carolina Driver’s Handbook provides guidance on this:
“The faster you are moving, the farther ahead you must be able to see to allow enough distance for stopping.” (p. 46)
“Never drive at a speed at which you cannot stop within the distance you can see on the road ahead” (p. 62)
Slow or stopped traffic may be present on any road at any time. Drivers must always be prepared to encounter garbage trucks, school buses, farm tractors, construction equipment, police officers, pedestrians, bicyclists and traffic congestion on most roads. Driving in a way that would endanger other road users who are stopped or traveling slowly is unlawful.
§ 20-141. Speed restrictions. (a) No person shall drive a vehicle on a highway or in a public vehicular area at a speed greater than is reasonable and prudent under the conditions then existing. … (m) The fact that the speed of a vehicle is lower than the foregoing limits shall not relieve the operator of a vehicle from the duty to decrease speed as may be necessary to avoid colliding with any person, vehicle or other conveyance on or entering the highway, and to avoid injury to any person or property.
§ 20-140. Reckless driving. (b) Any person who drives any vehicle upon a highway or any public vehicular area without due caution and circumspection and at a speed or in a manner so as to endanger or be likely to endanger any person or property shall be guilty of reckless driving.
Most drivers have no difficulty limiting their speed and seeing and slowing in time to avoid hitting vehicles traveling slowly ahead on the roadway. Impaired driving, reckless driving, distracted driving and bicycling at night without an adequate rear light or reflector are the primary contributing factors in car-bike collisions where motorists fail to slow in time to avoid rear-ending slower bicyclists.