BERGEN COUNTY, N.J. — Flooding problems that have already hit communities across Bergen County could become significantly more disruptive in the decades ahead, according to a new Rutgers University study examining the future of New Jersey's roadways.

The Rutgers research found that Bergen County is already experiencing coastal flooding impacts and projects that nearly 23 miles of roadway could be inundated within 50 years, along with 1.38 percent of the county's hurricane evacuation routes.

By 2100, under a scenario involving four feet of sea-level rise, the potential impact grows to 79 miles of flooded roadway and more than 10 percent of hurricane evacuation routes, according to the study.

The findings are particularly relevant for communities along the Hackensack River and its tributaries, including Fort Lee, Teaneck, Tenafly, Bergenfield, New Milford and Englewood, as well as lower-lying portions of Paramus and Fair Lawn.

The study does not provide individual projections for each of those municipalities, but its Bergen County findings underscore the broader regional problem: flooding that today may close an individual street or overwhelm drainage systems can increasingly affect major transportation routes and emergency access as sea levels rise.

Rutgers researcher Jonathan Delura used LiDAR-based roadway elevation data to estimate how much of New Jersey's road network could be affected under current conditions and future sea-level-rise scenarios. The analysis examined roadway flooding at present, under a roughly two-foot sea-level-rise scenario around 2050 and under a four-foot scenario by 2100.

The issue is not simply a concern for waterfront communities.

New Milford and Teaneck, for example, have already been dealing with chronic drainage problems. Bergen County officials approved drainage projects in both communities this summer following repeated flooding concerns.

Fair Lawn, meanwhile, has dealt with flooding along the Passaic River and other low-lying areas, while Paramus has experienced repeated roadway flooding during major rain events.

In the eastern part of the county, Fort Lee and Englewood face a different set of challenges because of their proximity to major waterways, steep terrain and heavily traveled roads. Bergenfield and Tenafly likewise can experience significant roadway flooding during intense rainfall even though they are not directly on the county's major coastal waterways.

The Rutgers study warns that roadway flooding can have consequences well beyond temporary inconvenience. Flooded roads can interfere with commutes, deliveries, access to hospitals and other essential services and emergency response operations.

And the problem can begin before a major storm.

The research found that so-called nuisance flooding during ordinary high tides is already capable of putting significant portions of New Jersey's road network underwater. Those impacts expand substantially under future sea-level-rise scenarios.

Bergen County is not projected to be among New Jersey's hardest-hit counties. The greatest roadway impacts are expected in places such as Ocean, Cape May, Cumberland and Salem counties. But Rutgers researchers say Bergen is still vulnerable and that its exposure grows considerably over time.

The study also raises a warning for emergency planners. Preparing solely for conditions expected around 2050 may not be enough, researchers said, because roadway and bridge flooding increases substantially between the 2050 and 2100 scenarios.

For Bergen County communities where flooding is already a recurring problem, that could mean that today's drainage and road closures are an early indication of a much larger infrastructure challenge.

Rutgers has made four data layers from the analysis publicly available, allowing transportation planners, floodplain managers and the public to examine potential roadway flood risks in greater detail.