Anyone familiar with the coefficient of expansion of concrete realizes the necessity of providing adequate expansion joints; also the necessity to eliminate intermediate cracks by creating planes of weakness to predetermine the location of contraction cracks. In their zeal to lower the cost of concrete construction, some engineers have been using only sawed joints, completely disregarding the important function of properly spaced through expansion joints. We must remember that although a sawed "plane-of-weakness" joint does serve a valuable purpose, it should only be used between properly spaced through expansion joints ... and not as a substitute for the necessary expansion joints. As in every engineering project, the economy of construction of a pavement should be judged not by its initial cost but by the total of the annual costs incurred over its service life. Although expansion joints will add slightly to initial cost at the time of construction, they provide a substantial reduction in maintenance costs over the years. A reduction in annual maintenance costs means that public expenditure can be reduced, or additional mileage of pavement provided, for the same expenditure of funds. The promiscuous elimination of expansion joints in modern day highway construction has added appreciably to maintenance costs. After proper provision of the necessary expansion joints, contraction joints should be used to relieve tensile stress caused by a decrease in volume of the concrete, and in some cases to control "warping stresses" associated with a temperature differential between the top and bottom of the slab. The most commonly used type of contraction joint, in order to function properly, must be in straight and true alignment. After all, it is inserted to create a plane of weakness; hence what we really have in a so-called dummy joint is an unknown factor of slab fracture. A known factor of slab fracture can only be accomplished by installing a through contraction joint; that is a joint that runs from the top to the bottom of the concrete slab; or a trapezoidal design, such as the commonly used tongue and groove joints. The trapezoidal design has long proven its efficiency in use as center longitudinal joints. There is evidence in a good many of our older highways that sawed longitudinal joints tend to encourage spalling. It is the writer's opinion, therefore, that engineers should carefully re-evaluate their design practices. We have an obligation to build highways that will provide the most economical service lifetime.