HIGHWAY SURVEYS 
Much has been written and published regarding the principles 
and techniques of making highway surveys in each of the respective 
stages of highway engineering. Consequently, it is not the purpose of 
this paper to iterate such details. Instead, the accuracy of highway 
surveys will be presented, especially those accomplished by use of 
aerial photogrammetric methods. 
From dictionary definitions of accuracy, it can be said that 
accuracy is freedom from mistake or error; a conformity to truth or 
some standard or model; or the deviation of a result, as obtained by 
a particular method, from the value accepted as truth. Another aspect 
of accuracy may be summarized from the dictionary definition of accu- 
rate. It can be said that accurate means being in exact or careful 
conformity to truth or to some standard, or to being free from error 
or mistake, especially as a consequence of care taken in doing the work 
or in making the measurements. 
By using such definitions, it can be said that all highway sur- 
veys have accuracy. They are accurate according to purpose, because 
the standards of accuracy are flexible. Moreover, the standard or 
model of comparison changes. The changes occur because of need or 
use. Thus, before the accuracy of highway surveys can be defined 
appropriately, the purpose snd use of each survey must be understood 
and appropriate standards of accuracy determined. 
Highway Planning. 
Among the significant aspects of planning are determining the 
highway traffic services needed and establishing the priority in which 
highway surveys are to be made, subsequent design undertaken, and con- 
struction accomplished, to fulfill traffic needs using the funds avail- 
able. The planning process must include the determination and 
utilization of data regarding land use--existing and future--which will 
have an effect on the traffic to be served and on traffic movements 
onto, along, and off each highway. 
Throughout areas or regions now lacking highways, potential land 
uses are especially significant because the highways, when constructed, 
will serve as corridors for vehicle movement to open each significant 
area for development and will, as a result, radically change land use 
or its intensity. 
To fully complete the acquisition of data for accomplishment of 
planning, the desire lines in urban areas between places of residence 
and work, or business, shopping, recreation, and so forth, and the 
type and number of vehicles which will move between such places to 
serve the land users must be estimated. In addition, vehicle move- 
ment--the number of vehicles per traffic lane, and the speed at which 
they can conveniently and safely move within each lane and from one 
lane to another, as necessary--will likewise be vital elements of 
planning.