11870b5d_oric_Significance_Rating__HSR___Description
[HSR] 2 [Examples] Larger multi-span 1940s-1950s stringers. Old expressway overpasses. Small pre-1940 stringer bridges. Small concrete slab design bridges. Small rigid-frame bridges. [Description] 
Bridges that are common technology, but may retain historic integrity or be large examples of their type, and thus are good examples of period technology.
HistoricBridges.org - Historic Significance Rating (HSR)
Description