“The bridges in question, most of which were constructed between 1910 and 1930, were part of a campaign to deal with a river that was prone to flooding and had destroyed many of the metal truss bridges built in the 1840s.
“Beautification was also a goal: In 1903, the L.A. Municipal Art Commission wrote that the city had to ‘work for the gradual elimination of ugliness from the conspicuous parts of our city.’
“The result was a recommendation to begin construction of the Art Deco and beaux-arts bridges that today extend from downtown to Boyle Heights, Cypress Park and Lincoln Heights. Sculpted into the Washington Boulevard Bridge are scenes that depict the men who built it. In muted colors, the figures are shown drilling, pushing wheelbarrows and carrying beams.”
Looking out for L.A. River’s bridges, By Daniela Perdomo, Los Angeles Times Staff Writer, LAT, January 28, 2008 (via Bottleneck blog)
We do have nice bridges in LA, if you live in the right part of town.
Pdf of the LA Bridges article, if the link is bad.