Science Fair Project Encyclopedia
Western vehicular traffic is generally organized, flowing in lanes of travel for a particular direction, with interchanges, traffic signals, or signage at intersectons to facilitate the orderly and timely flow of traffic. Vehicles also generally travel at the same speed on a given roadway.
Organized traffic typically reduces travel time. Though vehicles wait at some intersections, wait time at others is much shorter. Organized traffic degenerates to disorganized with an unexpected occurrence, be it road construction, an accident, or an animal obstructing the road. On particularly busy freeways, a disruption can persist until traffic thins. William Beaty observed persistent disruptions and named the phenomenon traffic waves.
Unorganized traffic occurs in the absence of lanes and signals. Roads do not have lanes, though drivers tend to keep to the appropriate side if the road is wide enough. Drivers frequently overtake other drivers, and obstructions are not uncommon.
Intersections have no signals or signage, and a particular road at a busy intersection may be dominant (that is, its traffic flows) until a break in traffic, at which time the dominance shifts to the other road where vehicles are queued. At the intersection of two perpendicular roads, a traffic jam results if four vehicles face each other side-on.
Brian Lucas answers the question, About 34% of the world by country population drives on the left, and 66% keeps right. By roadway miles, about 72% drive on the right.
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