18 
PHOTOGRAMMETRY IN HIGHWAY DESIGN IN SWEDEN 
  
by Bengt Adolfsson, 
The National Swedish Road Administration 
e INTRODUCTION 
Photogrammetry has been applied to highway design in Sweden for 
the last twenty years. The basic principles are still valid and 
will be described below. 
The development of the society causes changes in the po- 
licy concerning transport and communications. The system for 
highway planning and design has to be modified to meet require- 
ments for new and extended information about a highway project, í 
e.g. aesthetics, environmental conditions and traffic safety. 0 
Other requirements may concern topography, type of soil, ground 
stability, availability of suitable construction materials, land 
use and costs, traffic data, construction and maintenance costs 
etc. These circumstances together with the technical development 
of new photogrammetric and geodetic instruments, photographic 
materials, methods of evaluation of aerial photographs, computer 
systems etc, have modified the use of photogrammetry in highway 
design during the years. 
The most significant advantage of using a photogrammetric tech- 
nique as part of a highway design system as opposed to a design 
system entirely relying on ground survey methods is that the 
aerial photographs contain a large amount of qualitative and 
quantitative information that is readily available for use. More- 
over, the photogrammetric technique makes it easy to adapt a 
proper and economical survey or evaluation method to meet va- 
rious requirements on accuracy in different design stages. This 
is done in the first place simply by varying the scale of the 
aerial photography. Thus it is possible to meet the needs for a E 
general survey over large areas with limited requirements on 
accuracy for the route location and the needs for a detailed 
Survey over narrow areas with high requirements on accuracy for 
the final design. 
Since photogrammetry is only one part of the whole highway de- 
sign system it is very important that the combination of photo- 
grammetry, photo interpretation, ground survey, data processing 
and automatic plotting is organized in a simple and logical way. 
This is particularly valid in an organization like the Swedish 
Road Administration where the design work is decentralized. The 
combination has to be made in such a way that the design engineer 
can use it as an aid for improved data aquisition and processing 
and thus be able to devote his time to real engineering work and 
technical and economical analyses and judgements. 
In the following presentation, the current use of photogrammetry 
will be related to the different stages of a road projekt namely T 
a) route location, 
b) preliminary design, 
c) final design. 
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