HISTORIC AMERICAN HIGHWAYS^ — ROSE 511 



to the congestion of traffic at level crossings where long queues of 

 motorists used to be blocked while waiting for an opening through 

 lines of shifting freight trains (pi. 16, fig. 2). 



The fruits of comparatively small expenditures for roadside im- 

 provement became noticeable even before 1937. Encouraged by the 

 Federal Government this landscaping and planting work is restoring 

 rapidly the natural beauty of American roadsides. Gently rolling, 

 grass-covered side slopes are built to replace water-worn steep em- 

 bankments. This skillful treatment pleases the eye and pays extra 

 dividends in added safety and the prevention of soil-destroying 

 erosion (pi. 17, fig. 1). 



A prediction concerning future trends and innovations in road 

 building can be ventured only with the utmost caution. The 

 long-distance view beggars the imagination. In the immediate 

 future, however, it seems certain that there will be continued 

 the present efforts to speed the free flow of traffic. Many express 

 highways soon will conduct entering traffic safely and quickly 

 to the hearts of the big cities. Alternate belt-line routes will speed 

 travel around metropolitan areas within the suburbs. Complete 

 separation of opposing and intersecting traffic streams and the con- 

 struction of pedestrian and bicycle paths, as illustrated in plate 17, 

 figure 2, will make future main highways ideally safe and efficient. 



In proof that these future predictions have a solid foundation 

 there is presented an engineering masterpiece of the twentieth cen- 

 tury — the San Francisco-Oakland Bay Bridge (pi. 18). As a 

 dramatic conclusion to this pictorial history of the highways of 

 America this product of the young and vigorous West symbolizes in 

 all its strength and beauty and by its self-evident usefulness — the 

 highways of tomorrow ! 



