Effectiveness of additional lanes at signalized intersections.

This article explores the issue of whether increasing the number of lanes at signalized intersections could prove to be a sustainable approach to satisfy traffic demand only if larger intersections had economies of scale, or at least did not have diseconomies of scale. It is shown that the effectiveness of additional lanes decreases as the size of the intersection increases. Effectiveness is expressed in terms of marginal capacity increase of additional lanes, vehicle delay, and queue lengths. Ultimately, adding traffic lanes may reduce congestion in the short term, but is not sustainable in the long term. (Author/Publisher)