In the early-to-mid-1910s, the affluent population of Pasadena, CA, had the most automobiles per capita than any other city in the US, 5,000 for every 40,000 people. To enable the flow of auto traffic over the steep sides of the Arroyo Seco separating Los Angeles, CA, from Pasadena, CA, local government officials agreed to pool approximately $250,000 to erect the Colorado Street Bridge in 1912-1913. The Los Angeles County Board of Supervisors allotted $100,000 to the project, with the City of Pasadena contributing $100,000 and the Los Angeles City Council appropriating a like amount. (Pasadena voters approved a bond issue for this purpose in the Spring of 1912.) Los Angeles would control the western side of the 1,467 and 1/2-foot-long, 28-foot-wide bridge, while Pasadena oversaw the east. Right-of-way property was purchased primarily from the Family of J.W. Scoville (1825-1893), which still owned much of the arroyo floor and hillsides. The engineering firm of Waddell and Herrington created the engineering design for the Colorado Streeet span. The site had two complicating factors: the ground sloped down from east to west 30 feet, and bedrock was not uniformly distributed under the span's foundations. Fortunately, Dr. John Alexander Low Waddell had pioneered new bridge designs, including foundation plans that could provide consistent support despite irregular subsurface conditions. Waddell's firm had done several bridges in the Western US, including the Columbia River Interstate Bridge connecting Portland, OR, and Vancouver, WA, and spans in Tacoma, WA. He devised a reinforced concrete arch design to span the canyon; eleven arch supports composed the structure. Along the West Coast, reinforced concrete became widely used after the 1884, when the engineer Ernest L. Ransome (1844-1917) employed the material reinforced by cold-twisted, steel reinforcing bars for the structures of warehouses in Northern CA and the Stanford Art Museum at Stanford University (1893). Reinforced concrete became de rigueur for construction of large-scale buildings following the catastrophic San Francisco Earthquake of 04/18/1906. The Mercereau Bridge and Construction Company of Los Angeles, CA, submitted the low bid to erect Waddell and Harrington's engineering design. John Drake Mercereau, who had expertise in building concrete fishing piers, headed the company. Consulting Engineer C.K. Allen collaborated with both Mercereau and Waddell and Harrington to adapt their design to the site, decreasing the bridge's grade and length. Mercereau was cautioned to economize wherever possible, necessitating limited amounts of equipment on the job site and use of labor-saving methods for producing and laying concrete. Work, undertaken, at times, by 100 men and supervised by project superintendent F.W. Crocker of Mercereau, began in the middle of 07/1912 and concluded on 12/13/1913. At the dedication on the latter date, engineer Waddell did not appear, perhaps due to dissatisfaction with bridge alterations. Four workers lost their lives when falsework, (temporary supports), failed; three died at the scene, one later of injuries suffered from the accident.

Three engineering firms vied for the Colorado Street Bridge design commission in 1912: Kansas City, MO-based engineering firm of Waddell and Herrington, Young Construction Company of Los Angeles, CA, and engineers Parker and Mayberry of Los Angeles. While the first firm won this competition, the last constructed a small bridge under the Colorado Street Bridge, appropriately named the "Parker and Mayberry Bridge." The Colorado Street Bridge came under the auspices of the State of California Highway System in 1934. A beloved local landmark, the American Society of Civil Engineers (ASCE) designated in an Historic Civil Engineering Landmark in 1975. The City of Pasadena gave it landmark status in 1979, and the National Park Service (NPS) added it to the National Register of Historic Places on 02/12/1981.

Local subscriptions of $80,000 from Pasadena residents paid for widening of the eastern approach to the bridge in 1915. Due to a large number of suicides committed by people jumping off the bridge (particularly during the Depression), officials mounted fences safety fences in 1937 at a cost of $7,500. Due to a 5.9-magnitude earthquake that occurred on 10/01/1987 epicentered in the southern San Gabriel Valley (at Whittier Narrows), the Colorado Street Bridge received significant damage. Due to structural weaknesses, it was closed in 1989, and arches and foundations underwent a full-scale renovation before reopening in 1994.

Pressure to tear the bridge down came and went over the years. During the early 1930s, calls began for demolition, and repeated in the late 1940s and the 1980s. The State of California, Department of Transportation, sought to tear the bridge down just after World War II in preparation for the construction of the Foothill Freeway (US Highway 210); local pressure was so great, that the bridge was spared, and Caltrans built its own bridge nearby.