A proposal to rebuild one of Miami-Dade's busiest and most dangerous corridors is picking up steam, but its real deadline isn't political — it's structural. Commissioner Raquel Regalado's vision for the Rickenbacker Causeway, known as The Shoreline, calls for lifting regional through-traffic onto an elevated viaduct and turning the ground level into a slower, safer local road lined with parkland and protected bike lanes. The idea sounds ambitious, but it's tethered to the fate of an 80-year-old bridge that engineers say is already failing.
According to Miami's Community Newspapers, Regalado has framed The Shoreline as a way to improve traffic flow, create safer pedestrian and bicycle pathways, expand public green space, and reconnect residents with the waterfront. The plan draws direct inspiration from The Underline, Miami's linear park beneath the Metrorail, and envisions blending transportation, recreation, and coastal resilience into a single corridor. As the outlet notes, it remains a vision under consideration rather than a funded, finished project.
Plusurbia Design, the urban planning firm behind the concept, laid out the engineering specifics in October: a 30-foot viaduct carrying four lanes of regional traffic at 45 mph, with the ground level converted into a 30-mph local roadway featuring a dedicated linear park, protected bike lanes, and pedestrian promenades, according to Plusurbia Design. Today's causeway forces cyclists to share pavement with vehicles routinely topping 45 mph, the firm notes — a conflict The Shoreline is specifically designed to eliminate.
A Bridge on Borrowed Time Sets the Clock
The urgency behind the push traces back to the Bear Cut Bridge, an 80-year-old span whose condition is under study. A Florida Department of Transportation load rating report gave the bridge, built in 1944 and widened in 1983, a sufficiency score of just 37.3 out of 100 in June 2024 — low enough to make it eligible for full replacement, according to Miami-Dade County.
That finding set a bureaucratic clock in motion. In October, Miami-Dade County finalized an agreement with FDOT for a Project Development and Environmental study running through March 2027 to weigh repairing the bridge against replacing it outright, per the county.
Money Follows the Vision, Slowly
Local buy-in has already produced real dollars. The Key Biscayne Village Council voted 6-1 in November 2025 to commit $950,000 toward feasibility, engineering, and design studies for The Shoreline, according to WLRN. Council Member Ed London cast the lone dissenting vote, calling the expenditure a waste of public money.
Before that public money arrived, the station reported that developer David Martin of Terra Group had underwritten initial preliminary design work for The Shoreline at an undisclosed cost.
County Mayor Daniella Levine Cava has tempered expectations, warning in November that state tax cuts have squeezed Miami-Dade's transit budget and that the county cannot finance a project of this scale on its own, the same WLRN report states. Commissioner Regalado pushed back, pointing out that Levine Cava was initially hesitant about The Underline before becoming one of its supporters.
The Safety Case and a Regional Traffic Problem
The corridor's traffic numbers help explain why safety has become the project's central argument. The Rickenbacker Causeway carries more than 10 million vehicles a year, including approximately 28,000 daily vehicle trips through Virginia Key to and from Key Biscayne, per Plusurbia Design's published figures. The firm says elevating through-traffic is meant to pull those daily vehicle trips off the surface roads that currently run past beaches and recreational areas.
Traffic consultant Kimley-Horn found that two-thirds of the 58,000 vehicles crossing the causeway on peak weekends are visitors headed to Virginia Key and Crandon Park, not Key Biscayne residents, WLRN reported in June 2025 — evidence that the congestion is a countywide problem rather than an island-only concern. Weekend volumes on the corridor spike well above typical daily averages as a result.
The human stakes behind the safety argument are clear on the causeway. The Rickenbacker Causeway is one of the county's most heavily used cycling routes and has seen multiple fatal bicycle and e-bike crashes, a toll Hoodline has chronicled directly — in a severe SUV collision that left a Miami surgeon paralyzed in the causeway's bike lane just weeks ago.
The Underline as Proof of Concept
Supporters point to The Underline as evidence the model can work at scale. The 10-mile linear park beneath Miami's Metrorail, which inspired The Shoreline's design, reached a five-mile milestone in May. Eulois Cleckley, CEO of Friends of The Underline, is now managing the feasibility study for The Shoreline as well.
Whether that track record translates to a far more complex project — one that must thread a viaduct, a linear park, and a legally mandated bridge study into the same timeline — remains an open question. For now, The Shoreline is still a concept awaiting the kind of detailed engineering and funding commitments that turned The Underline from a sketch into a trail. Its fate may ultimately hinge less on Key Biscayne's enthusiasm than on what federal and state engineers decide about Bear Cut Bridge by March 2027.
