Traffic slowed to a trickle Monday as construction as work began on the flyover from the MacArthur Causeway that takes drivers to Miami Beach via Alton Road.
The construction work to replace the guardrail and rebuild the base will mean the closure of the flyover for 30 days, according to the Florida Department of Transportation.
The effect was immediatly felt as motorists trying to get to the beach from the mainland got caught in bumper-to-bumper traffic.
Drivers used to veering left at the end of the causeway to take the flyover and bypass a series of intersections were instead left at the mercy of traffic lights at the foot of the causeway and beyond.
If the project runs behind schedule, the contractor would be charged $5,000 a day for up to five days.
The logjam at the MacArthur Causeway on the first morning of construction did not seem to affect other crossings between the mainland and the beach.
Tollworkers at the Venetian Causeway, the nearest connection between the beach and mainland and about a mile north of the construction at Alton, said they did not notice any increased traffic coming from the mainland.
The Florida Department of Transportation has provided these detour routes for travelers:
Motorists will not be able to cross east or west on Alton Road at Sixth Street.