Clarke and Wright's savings trick made delivery routes computable by hand

In 1964, G. Clarke and J. W. Wright, working with the Cooperative Wholesale Society in Manchester, published 'Scheduling of Vehicles from a Central Depot to a Number of Delivery Points' in Operations Research. Their target was the routing problem Dantzig and Ramser had formalized in 1959 — and for which exact solutions were too slow to compute.

Their savings algorithm is almost embarrassingly simple: start with a separate round trip for every customer, then for each pair of customers compute how much distance you save by serving them on one trip instead of two; merge pairs in order of largest saving, as long as vehicle capacity allows. A University of Southern Denmark course still teaches it as the classic constructive heuristic for capacitated vehicle routing.

It worked where exact methods did not: routes could be computed by hand or with early computers, and the method became a standard building block — a strong starting solution that later metaheuristics like 2-opt, tabu search and genetic algorithms refine.