[4] A 1953 extension brought the south end to the Four Level Interchange in downtown Los Angeles and a connection with the rest of the freeway system.

In 2010, as part of plans to revitalize its scenic value and improve safety, the California Department of Transportation (Caltrans) restored the roadway's original name.

The 1895 Santa Fe Arroyo Seco Railroad Bridge (now A Line) lies just beyond, and after that is a half diamond interchange at Marmion Way/Avenue 64 with access towards Los Angeles only.

The latter was partially constructed and opened by Horace Dobbins, who incorporated the California Cycleway Company and bought a six-mile (10 km) right-of-way from downtown Pasadena to Avenue 54 in Highland Park, Los Angeles.

Due to the end of the bicycle craze of the 1890s and the existing Pacific Electric Railway lines connecting Pasadena to Los Angeles, the cycleway did not and was not expected to turn a profit, and never extended beyond the Raymond Hotel into the Arroyo Seco.

Sometime before 1910, the structure was dismantled, and the wood sold for lumber,[10][11] and the Pasadena Rapid Transit Company, a failed venture headed by Dobbins to construct a streetcar line, acquired the right-of-way.

[12][13] Due to the rise of the automobile, most subsequent plans for the Arroyo Seco included a roadway, though they differed as to the purpose: some, influenced by the City Beautiful movement, concentrated on the park, while others, particularly those backed by the Automobile Club of Southern California (ACSC), had as their primary purpose a fast road connecting the two cities.

Frederick Law Olmsted Jr. and Harland Bartholomew's 1924 Major Street Traffic Plan for Los Angeles, while concentrating on traffic relief, and noting that the Arroyo Seco Parkway would be a major highway, suggested that it be built as a parkway, giving motorists "a great deal of incidental recreation and pleasure".

[17] To connect the proposed parkway with downtown Los Angeles, that city improved and extended North Figueroa Street as a four-lane road to the Los Angeles River, allowing drivers to bypass the congested North Broadway Bridge on the existing but underutilized Riverside Drive Bridge.

The state, which had the power to put the road where it wished even had South Pasadena continued to oppose it, approved the route on April 4, 1936.

A number of state engineers toured East Coast roads in early 1938, including Chicago's Lake Shore Drive, full and modified cloverleaf interchanges in Massachusetts and New Jersey, and Robert Moses's parkway system in New York City.

The parkway was the first road built in California under a 1939 freeway law that allowed access to be completely limited to a number of specified points.

(By mid-1939, the state had decided to replace the shoulders with additional travel lanes for increased capacity; except on a short piece in South Pasadena, these were also paved with Portland cement.

[28] In South Pasadena, seven streets and the Union Pacific and Santa Fe railroad lines on a double track combined bridge were carried over the parkway to keep the communities on each side connected.

The two-way Figueroa Street Tunnels and Viaduct were repurposed for four lanes of northbound traffic, and a higher southbound roadway was built to the west.

The new road split from the old at the Figueroa Street interchange, just south of Avenue 26, and crossed the Los Angeles River and the northbound access to Riverside Drive on a new three-lane bridge.

Through Elysian Park, a five-lane open cut was excavated west of the existing northbound tunnel lanes, saving about $1 million.

The short city-built Cahuenga Pass Freeway opened on June 15, 1940,[36] over a month before the second piece of the Arroyo Seco Parkway was complete.

In the next two decades, the Harbor, Hollywood (Cahuenga Pass), Long Beach (Los Angeles River), San Bernardino (Ramona), and Santa Ana Freeways were partially or fully completed to their eponymous destinations, and others were under construction.

Except for the Golden State Freeway (I-5) interchange near the river, completed in 1962, the few structural changes to the freeway north of the river include the closure of the original southbound exit to Fair Oaks Avenue after its location on a curve proved dangerous[11] and the replacement of shrubs in the 4-foot (1.2 m) median with a steel and now concrete guard rail.

Los Angeles paid for reconstruction of the interchange at Hill Street, south of Elysian Park, in the early 1960s to serve the new Dodger Stadium.

The parkway's design is now outdated, and includes tight "right-in/right-out" access with a recommended exit speed of 5 miles per hour (8.0 km/h) and stop signs on the entrance ramps.

[citation needed] There are no acceleration or deceleration lanes, meaning that motorists must attempt to merge immediately into freeway traffic from a complete stop.

A three-year Caltrans study determined that the parkway has a crash rate that is twice that of comparable highways, with the primary factor being the lack of acceleration and deceleration lanes.

The state legislature designated the original section of the Parkway, north of the Figueroa Street Viaduct, as a "California Historic Parkway" (part of the State Scenic Highway System reserved for freeways built before 1945) in 1993;[46] the only other highway so designated is the Cabrillo Freeway (SR 163) in San Diego.