Abstract
In recent years thousands of miles of freeway-type highway have been constructed to provide for the safe,convenient and efficient transportation of persons and goods.Access to these facilities is provided by on-rampe designed to merge ramp traffic movement on freeways, and the exgent to which the potential eapacity of free- ways can be realized depends in part on the adequancy of the access facilities,Improperly designed entrances limit the volume of traffic that can use an expressway and generate congestion that often extends ba.k onto the local system.