KEY BISCAYNE (CBSMiami) –Modifications to three bike lanes on the Rickenbacker Causeway to make them safer for cyclists are underway.

The work was originally scheduled for last week but because of all the rain and the holiday weekend, work on the modifications was moved to this week.

The existing bike-lane striping on the William Powell and Bear Cut bridges is getting a second white line with “vibratory ridges” to the outside to create a larger buffer between bicyclists and drifting motorists.  Unlike rumble strips, the vibratory ridges are placed 30 inches apart to allow cyclists to maneuver in an out of the bike lane if encountering debris or obstacles.

A second white lane will also be added to the West Bridge, which connects the toll booths on the Miami mainland to Hobie Beach.

The modifications are part of several promised safety improvements after two cyclists were fatally struck while riding on the bridge.

Triathlete and businessman Aaron Cohen was killed when he was struck from behind by a hit & run driver February 15 while riding with a companion. Michele Traverso, 25, was arrested and charged in Cohen’s death.

In January 2010, Christophe LeCanne was also struck from behind by a hit & run driver while riding on the Rickenbacker.

Carlos Bertonatti was arrested and charged in LeCanne’s death. He is still awaiting trial.