PennDOT officially designates part of U.S. Route 15 as I-99

“Today’s designation of U.S. 15 as I‑99 is more than a marker on a map, it reflects the investment, collaboration, and engineering excellence of countless individuals who understood how vital this route is to the future of the region,” Secretary Carroll said. “This new interstate connection will strengthen the region’s economy by improving freight movement, increasing safety, and open new doors for business growth. As we move forward, this corridor will continue to support community growth and create new opportunities by ensuring that the region remains connected, competitive, and thriving for generations to come.”

The Federal Highway Administration (FHWA) granted the designation after determining that the corridor meets all federal standards for interstate design, safety, and performance.

Since 1984, PennDOT has been modernizing U.S. 15 into a continuous, limited-access highway. These improvements were delivered through 34 projects totaling an investment of $480 million, which included new alignments, upgrades to shoulders, pavement, access points, and roadway geometry. New signage has been installed along the 62‑mile corridor and started being uncovered on July 30.

“The completion of I-99 marks a transformative milestone for our region,” said PennDOT District 3 Executive Eric High. “One built through decades of investment, persistence, and partnership. This designation strengthens the connections for businesses, travelers, and communities and reflects our commitment to building infrastructure that supports long-term growth.”

The I‑99 designation is also expected to improve regional connectivity by linking key routes, including I‑80 and I‑86, making travel more efficient for residents, visitors, and commercial carriers. In the long term, the upgraded corridor is likely to bolster local economies by attracting business investment and improving overall travel clarity and consistency.

The new I-99 designation also marks a shift from the current allowances for companies that hold annual over-dimension hauling permits. Under federal interstate regulations, the maximum allowable weight for divisible loads will be reduced from 95,000 pounds to 80,000 pounds unless a federal exemption applies.

• In accordance with federal law, once designated as I-99, the weight restriction will be reduced to 80,000 pounds for divisible loads.

• Divisible overweight permits will no longer allow travel on the designated section.

• Milk haulers are permitted under federal law to operate overweight on interstates including the future I-99 corridor.

• Haulers will be required to comply with the weight limits or reroute using alternate, approved state routes under their current Annual Network permits.

• Starting July 30, the Automated Permit Routing and Analysis System (APRAS) will prevent the issuance of new divisible overweight permits for I-99.

• Permits for non-divisible oversize or overweight loads will continue to be issued and remain valid for travel along I-99.

Annual permit holders impacted by the upcoming changes received advance notice in late 2025 and in early July upon federal approval of the designation.