(c) Standardized structures require less skilled labor than improvised structures.

(d) Standardization promotes uniformity in training and practice.

(e) A standardized structure is nearly always superior to an improvised structure in every item of utility.

(f) In a hasty, improvised bridge constructed of random materials, the actual strength of the structure is usually a matter of uncertainty and guess-work. In standardized designs the safe loading is accurately known, and the chance of accident from overloading the structure is correspondingly reduced.

The benefits of standardization being so manifest, standardized-type plans have been prepared for all forms of military bridges, even for those constructed of local materials. Standardized material for these structures is prepared in the engineer shops, so as to reduce as far as possible the amount of labor required in the field. Standardized designs are, or should be, of the utmost simplicity and flexibility. They should be simple, because only the simplest structures can be successfully and promptly erected under the difficult conditions incident to warfare, involving lack of time, adequate tools and plant, skilled labor, etc. They should be flexible, because no two situations are exactly alike; and the type plans must be modified in practice to meet the actual conditions. It should be possible, with a few minor variations, to adapt the type plans and the standard materials to any situation, with a minimum of improvisation. The best example of standardization in military bridging is the sectional steel truss heretofore described.

It has been said that standardization has a tendency to discourage invention, and hence is inimical to progress. While it must be admitted that there is some truth in this contention, the tremendous results that have been achieved through standardization, in both civil and military practice, are a sufficient justification for its adoption. There will be an ample field for the inventive talents and resourcefulness of the engineer, both within and without the limitations imposed by standardization. Moreover, for every inventive genius who has been discouraged by standardization there are thousands of average men who have profited by it; and it is the average man with whom we invariably reckon in military operations of all kinds. Standards should be revised and improved in the light of experience; and this was frequently done during the World War.

Because of the density of traffic and the heavy loads incident to modern military operations, standardized bridge designs will be employed more frequently in the future than they have been in the past. There were times during the World War when the regular daily traffic on a single road was 5000 motor trucks (in both directions), and during troop movements this reached a maximum of more than 17,000. Rough, improvised structures would not be adequate to the needs of such a traffic.