A two-lane highway in Denton County, Texas, long overwhelmed by some of the fastest suburban growth in the country, is getting a federally funded reconstruction that officials say will cut both congestion and air pollution along one of North Texas's most strained corridors.

The stretch of US 377 between FM 1171 and Crawford Road, running through communities like Argyle and Northlake that have transformed from farmland to subdivisions in under a decade, will be widened from two lanes to four. The project, backed by a nearly $4.9 million federal grant, also includes new traffic signals, turn lanes, Texas U-turns to reduce signal conflicts, sidewalks, and a grade separation, meaning an overpass or underpass at an intersection so congested it can no longer be managed at ground level.

The money comes through the federal Congestion Mitigation and Air Quality Improvement Program, which specifically targets regions that fail to meet EPA clean air standards. The Dallas-Fort Worth metroplex has been in some form of ozone nonattainment since the early 1990s, and vehicle exhaust from stop-and-go traffic is a major contributor. The program's premise is direct: smoother traffic means less idling, and less idling means cleaner air.

Denton County has been among the fastest-growing large counties in the nation for years, roughly doubling in population from about 450,000 in 2010 to over 900,000 by the early 2020s. That growth has poured tens of thousands of new residents onto roads designed for a fraction of the demand. US 377 is a visible symptom of a broader mismatch: residential development in the corridor has consistently outpaced the infrastructure meant to support it, and local officials have been pressing for improvements for years.

With CMAQ grants typically structured on an 80/20 federal-to-local split, the total project cost is likely around $6.1 million or more, with TxDOT and regional partners covering the remainder. The North Central Texas Council of Governments, which programs federal transportation dollars for the DFW region, coordinates this kind of funding.

Whether the widening will provide lasting relief is an open question. Road expansions in fast-growing areas often attract additional traffic over time, a dynamic critics call induced demand. For now, TxDOT and local officials are moving forward. Construction timelines have not yet been publicly announced.