Excellent article on the 5 concrete bridges on the Van Duzen River highway . This article summarizes an article on these bridges that appeared in the March 25th number of the Western Construction News by Harold B. Hammill, consulting engineer of S.F. , who assisted in the design of these bridges. Places along the highway are mentioned - Blue Slide and Blackburn Grade. The old highway was located over these spots to keep it on the same side of the river - which during floods, is dangerous to cross. Shortly after the state selected this new route the county B.O.S. adopted a policy of road improvement. Two bridges were built to eliminate the Blue slide & two were built to elimatment the Blackburn Grade, while a 5th was built to replace the covered bridge at Bridgeville. All 5 of the new ones are conc. arch bridge of pleasing appearance. The article says these 5 are about the finest example of the bridge builders art to be found in CA.