CR 16A in St. Johns County to Close Two Weekends for Expressway Work

County Road 16A in northwest St. Johns County will close for two consecutive weekends next month as crews install underground pipes for the First Coast Expressway, the county announced Sunday. The closures will affect the segment between Timberwolf Trail and River Reach Parkway.

The roadway will be shut down from 8 p.m. Friday, July 31 through 5 a.m. Monday, August 3, then again from 8 p.m. Friday, August 7 through 5 a.m. Monday, August 10. Traffic will detour via State Road 16 and State Road 13 during both closure periods.

What's happening

The closures are scheduled for pipe installation that must cross County Road 16A as part of ongoing First Coast Expressway construction, according to the St. Johns County announcement posted July 20. The work requires complete roadway closure rather than lane restrictions.

Each closure will span approximately 57 hours from Friday evening through Monday morning. The affected segment runs between Timberwolf Trail and River Reach Parkway in the northwest portion of St. Johns County, an area experiencing rapid residential growth along the expressway corridor.

The official detour route directs drivers to State Road 16 and State Road 13. FDOT District 2 is managing traffic information related to the closures, which the county emphasized are necessary to complete the utility work safely.

Impact on northwest St. Johns County residents

The closures will require detours for residents in subdivisions along County Road 16A, including neighborhoods that use the roadway to access State Road 16 and points west. River Reach Parkway and Timberwolf Trail mark the northern and southern boundaries of the affected zone, covering a stretch that serves as a connector between established residential areas and the SR 16 corridor.

Weekend closures affect different traffic patterns than weekday restrictions. Residents making weekend trips for shopping, recreation, or family visits will need to add time for the SR 16 and SR 13 detour. The timing—beginning Friday evening and ending Monday morning—captures the full weekend period when families are most likely to travel locally.

Emergency vehicle access during the closures would follow the same detour routes, adding response time for fire, medical, and law enforcement services reaching addresses along the closed segment. Residents planning weekend activities should factor the closure into travel plans for both weekends in early August.

First Coast Expressway construction timeline

The pipe installation is part of the broader First Coast Expressway project, which is reshaping transportation and development patterns across Clay and St. Johns counties. The expressway, designated State Road 23, forms a tolled loop connecting I-95, US 17, and US 1, opening up previously rural land for residential and commercial development.

Construction of the expressway has proceeded in segments over several years, with the full loop substantially complete and operational. However, utility work, drainage improvements, and final roadway connections continue in various locations along the corridor. Projects of this type typically require coordinating with existing roadways where drainage pipes, stormwater systems, or utility lines must cross under state roads and county roads.

The work scheduled for these two weekends suggests the pipe installation involves infrastructure large enough or deep enough that it cannot be completed with lane closures alone—crews need the full roadway clear. The weekend schedule minimizes disruption to weekday commuter traffic, which is heavier on CR 16A during business hours.

Development growth along the SR 23 corridor

County Road 16A sits within the First Coast Expressway growth corridor, where residential development has accelerated significantly since expressway segments opened. The area between SR 16 and the World Golf Village area has seen numerous subdivision approvals and plat recordings as developers capitalize on improved highway access to Jacksonville employment centers.

Infrastructure work like this pipe installation reflects the ongoing challenge of upgrading local roads and utilities to keep pace with the residential boom. As the expressway reduces drive times to I-95 and downtown Jacksonville, subdivisions fill in around interchanges and along connector roads like CR 16A, increasing traffic volumes on roadways originally built for rural use.

The First Coast Expressway has effectively extended the Jacksonville metro commute-shed deeper into St. Johns County, making northwest St. Johns neighborhoods viable for families working in Jacksonville. That shift brings ongoing roadwork as FDOT, the county, and utility providers install the infrastructure that new rooftops demand—stormwater capacity, wider travel lanes, turn lanes at subdivision entrances, and the drainage pipes being installed during these CR 16A closures.

What happens next

The first closure begins at 8 p.m. Friday, July 31 and runs through 5 a.m. Monday, August 3. The second closure follows the next weekend, from 8 p.m. Friday, August 7 through 5 a.m. Monday, August 10.

Drivers can monitor real-time traffic conditions and lane closures through FDOT District 2's social media channels—@MyFDOT_NEFL on X and MyFDOTNEFL on Facebook—or by visiting nflroads.com. The FL511 website and mobile app provide live traffic alerts for travelers planning routes during the closure periods.

St. Johns County posts construction and road-closure updates through its e-newsletter system, which residents can subscribe to through the county website. No additional closures on CR 16A beyond the two August weekends have been announced, though expressway-related utility work in the corridor may require further roadway impacts as construction wraps up final phases.

The closures mark another milestone in the multi-year First Coast Expressway build-out, a project that has fundamentally altered development economics and traffic flows across Clay and St. Johns counties. As the expressway nears full completion, work shifts to the less-visible infrastructure—pipes, drainage, and utility crossings—that tie the new highway into the existing road network serving one of Northeast Florida's fastest-growing counties.