for detailed planning of the structure, 
STEP IV -- Final Earthwork Quantities 
After construction of the highway has been completed, 
new large scale photography may be obtained. This is 
used in conjunction with the cross section data obtained 
during the design phase to obtain "as built'' cross sections, 
which are used as a basis for payment to the contractors, 
The procedure just outlined employes photogrammetry very 
advantageously to reduce the cost and time and at the same 
time improve the quality of highway designs. But progressive 
engineers were far from satisfied. 
INTRODUCTION OF ELECTRONIC DATA HANDLING 
The most obvious immediate improvement which could be made 
was the substitution of electronic computation for the many 
hours of arduous work on desk calculators. One can hardly re- 
main in the highway design business now without having access 
to a computer of medium capacity. In general the computer 
programs are designed to perform automatically the same cal- 
culations which highway engineers had always done by hand. 
Modifications are introduced to integrate the computer more 
completely with other electronic data processing equipment. 
The second improvement seems to have occurred to several 
people at about the same time. This is an attachment, designed 
for use with the photogrammetric plotting instrument, which 
would digitally record cross section notes from the stereo 
model. The instrument (Figure 2) is aligned with the cross 
section line plotted on the map sheet, The modified tracing 
table platen is then attached. The stereoplotter operator sets 
the station number on the control panel. Then as he brings the 
index mark of the tracing table into coincidence with the 
terrain seen in the stereo model, the device automatically 
records the distance left or right of the center line and the 
elevation of the point. Through external connections, the 
device may be made to actuate an automatic typewriter or a card 
or tape punch unit, so that its output is directly useable in 
the electronic computer. 
A commercial version of this instrument, called the Terrain 
Data Translator, is now available from Benson-Lehner Corporation. 
It can, of course, also be used to take off cross section data 
from the topographic map used in the location studies. 
The next innovation was the elimination of the tedious 
routine involved in the drafting of alignment sheets, profiles 
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