Tragically, a witness saw what was happening and tried to save her — but she couldn't hang on.
"The woman tried to hang on," West Palm Beach police spokesman Mike Jachles told WPTV.
"There was a bystander nearby who tried to help her, but tragically she fell five or six stories below where she died landing on concrete."
The bridge was closed to traffic for more than six hours; an investigation is now underway into how the tragedy occurred.
"There is a bridge tender, and that bridge tender has certain safety protocols to follow, specific safety protocols," Jachles said, "that includes lowering of the gates for the vehicles, lowering of the gates for the pedestrians, and making several visual confirmations that there is nobody at either of the spans or past those gates."
Bicycle safety advocate Juan Orellana told the outlet that of the three bridges that connect Palm Beach Island to the mainland, Royal Park is the main one and frequently used by cyclists.
He said it is equipped with barriers and alarms that alert crossers the bridge is about to rise.
"For one thing you will hear the bell even before the arms go down, so when you hear the bell you gotta get out of the way before the bridge goes up," he said.
Investigators are reviewing security footage on the bridge. It is not yet clear if the woman ignored the safety warnings or was already on the bridge when the alarms went off; however police told WPTV she was "almost across" when she fell.