INTRODUCTION 
The opportunity of representing the Bureau of Public Roads and of pre- 
senting to the International Society for Photogrammetry a paper on The Role 
of Aerial Surveys in Highway Engineering imports recognition and honor which 
are sincerely appreciated. The professional quality of services by, and 
advancements of, the Society and its members are standards of excellence. 
Their achievements are far reaching and have had profound effects in our com- 
plex modern activities. In the future the effects will increase.  Govern- 
mental serving and privately practicing organizations, groups, and individu- 
als will feel, at an ever-increasing pace, scope, and intensity, the benefits 
from and their dependence on aerial surveys. 
Fields of endeavor requiring data on position and dimensions, and quali- 
tative information are, more and more, adopting and applying aerial surveys. 
Such data and information are significant in engineering, especially for high- 
ways, where many of the principal problems are inextricably associated with 
the earth and everything on it, its underground composition, and its physical 
forces. 
Aerial surveys fit perfectly into the patterns of sequential performance, 
on a scheduled basis, associated with teamwork requirements. Recent successes, 
and assurances of continuing success, can be ascribed to the effectiveness and 
efficiency attainable from appropriately utilizing aerial surveys. To main- 
tain this high level of performance, engineers and other specialists on the 
highway engineering team must continue to employ aerial surveys in each of 
their particular spheres of responsibility. 
Aerial surveys and highway engineering were aiding and supplementing 
companions for more than fifteen years before they were joined by the rapid, 
electronic methods of computation. Together they have since attained phenom- 
enally beneficial progress. Their combined successes can be attributed to 
their appropriateness, to the pressing need for more extensive comprehension 
and analyzation, within a relatively short time, of all of the intricate prob- 
lems which must be solved, and to the lack of additional qualified personnel 
for accomplishing such work by former methods. 
Among the principal advantages of aerial surveys for highways are the fact 
that highway surveys can be accomplished more rapidly and economically by aerial 
than by ground survey methods. A width of from two to nine times the width 
usually surveyed on the ground can be surveyed from the air at from one-half to 
one-eighth the cost of ground surveys. Moreover, aerial surveys properly 
employed add the benefits of improved locations and design which decrease con- 
struction costs and improve highway services. 
Aerial surveys in conjunction with electronic methods of computation have 
been and will continue, both directly and indirectly, to point to needs for 
improvements in ground surveying instruments and procedures. The demands made 
by highway engineering for compilation by photogrammetric methods of topo- 
graphic, planimetric, and cadastral maps at scales as large as 40 and 20 feet 
to one inch (1:480 and 1:240) were, and continue to be, challenges to the 
photogrammetric profession, both operationally and instrumentally. 
Engineering schools must keep their curriculum in pace with the changes 
and improvements brought about by the use of aerial surveys and provide suffi- 
cient instruction in aerial surveys, including improved ground surveying and 
electronic computation, to prepare engineers for entering the highway field. 
Likewise, there is the continuing challenge to all governmentally employed and 
privately practicing engineers, not only to keep abreast of the rapid change 
in methods and procedures, but also to anticipate new requirements and take 
the lead in making progressive contributions. I have faith that members of the 
member societies of the International Society for Photogrammetry will do their 
full share.