This paper outlines the process for achieving an optimal strategy for maintaining street lights in Pretoria, South Africa. The strategy focused on simple maintenance tasks, performed by semi-skilled workers, which form the majority of maintenance tasks performed by public authorities. This `best cost approach' was the result of a holistic modern research methodology with the following features: (1) use of national standards and guidelines; (2) identification and examination of public perceptions and expectations of maintaining urban lighting; (3) use of practical street light maintenance operations data to simulate lighting failures; (4) application of modern principles of maintenance, management, and engineering to integrate field data with expert and public opinion; (5) provision of a stochastic model to simulate maintenance operations; and (6) recommendation of maintenance operations that will maximise value for ratepayers. Many strategies were compared to obtain the best strategy for Pretoria. Public perceptions and simulated results were compared, and were usually highly correlated. The cost of repairing reported failures was largely determined by the number of normal working hours allowed to maintain the lights. Examples are given of the savings achieved by optimising the maintenance policy.
Samenvatting