should be located, designed, and constructed to provide the needed traffic 
capacity with qualities admitting movement of the traffic at fast speeds with 
: minimum interference from highway entering-and-leaving vehicles. On important 
ly, routes this often means control of access and use of curves (horizontal and 
"Obs vertical) that are smooth, easy, and long in combination with joining tangents 
x of appropriate length. It is good practice to make the surveys, to accomplish 
all engineering, and to procure rights-of-way of sufficient width, particu- 
larly for the important highways, which will accomodate the ultimate number of 
traffic lanes that may be required, although immediate construction to fulfill 
current and anticipated future traffic needs for the next decade or more 
require only 2 or 4 lanes. 
me 
  
A A low oblique view of & cloverleaf interchange on controlled access highway 
bordering a residential area. On the right is an improved and slope-protected 
drainage channel.