There are two construction projects in progress on map 84 of Atlantic Coast section 7.
1) A1A Little Lake Worth Bridge Replacement (http://www.d4fdot.com/pbfdot/A1A-Little_Lake_Worth_Bridge_Replacement.asp
): The bridge labeled as Jack Nicklaus Dr./SR A1A south of Juno Beach, just north of Lake Worth. This project will continue through the winter of 2012.
2) Little Blue Heron Bridge (http://www.d4fdot.com/pbfdot/PBC-Bridges_Little-Blue-Heron.asp
): The bridge on the Riviera Beach Detail Map labeled as Blue Heron Blvd./SR A1A. This project with continue through June 2012.
On both projects, lanes will remain open throughout the construction as well as sidewalk pedestrian access if you wish to walk your bike through.
We have also been advised there is an alternative route parallel parallel to US 1 -- Avenue A/Lakeshore Drive -- 1 starting at 20th St. E., eventually crossing Blue Heron Blvd, and extending north to Shore Court, where it joins US 1 at Northlake Blvd. US 1 between here and PGA Blvd. has paved shoulders and is a reasonable to bike.
This Google map shows the alternate route: http://g.co/maps/fwh8e