Palm Beach County purchased the middle bridge of Palm Beach’s three bridges—the Royal Park Bridge—from the Palm Beach Improvement Company, who had built it in 1911 to access their Royal Park subdivision. As the county replaced the wooden bridge in 1921, it collapsed during the final work after inspections, just two days before the planned dedication. Sara Moses Dean bicycled across it about four hours before the collapse, probably the only person to use the bridge. Judge James R. Knott described the event in his “Brown Wrapper” in The Palm Beach Post:
About 2 p.m., as a steamroller was packing the surface, the head of construction heard a cracking noise and ordered the machine off. He and an assistant raced onto a barge to investigate from the water line, but as soon as they did, a pier on the Palm Beach side gave way and the two spans crashed down, throwing workmen on the spans and the boat into the water.
Everyone was rescued, but later another span and another pier fell in. The bridge that inspectors had passed two days earlier was now a jumble of concrete chunks and steel rods. A civic uproar followed, with people calling for penalties for those responsible. A temporary wooden structure was built. … A suit against the construction company ended in a settlement.
The new bridge was opened to traffic in 1924, but the 1928 hurricane caused extensive damage; three months later it was still open only to foot traffic.
The Flagler Memorial Bridge, northernmost bridge to Palm Beach, replaced the 1902 Florida East Coast Railway Bridge in 1938, linking West Palm Beach to the island’s Main Street, now known as Royal Poinciana Way. Barracks and a railroad station were demolished, replaced by a median for the street.
A mini-boom was triggered in 1915 when the Florida legislature created the Lake Worth Inlet District, forerunner of the Port of Palm Beach, which established the present site of the Lake Worth (Palm Beach) Inlet. The first Port commissioners were elected by county election. Initially the inlet, which opened in 1920 and separated Singer Island from Palm Beach, was of insufficient depth for large ships. Consulting engineer General George Goethals, who built the Panama Canal, supervised additional dredging of the inlet and extension of the jetties in 1921-1923. The first oceangoing cargo ship entered the port in 1925.
Also in 1925, the first bridge was built across the Intracoastal Waterway in Lantana. The following year, just as the boom turned to bust, the Federal Highway was completed to Miami, a new bridge in Jupiter crossed the Loxahatchee River, and the Boynton Inlet opened.
Also in Boynton, the Ocean Avenue Bridge across the Intracoastal replaced the East Coast Canal Bridge in 1935.