The Commonwealth Transportation Board approved Tuesday the recommended design concept, known as the “Preferred Alternative,” for the I-66 Outside the Beltway Project, as well as a phased implementation approach. The preferred alternative is a combination of various alternatives that were evaluated over the past year to improve 25 miles of I-66 from I-495 in Fairfax County to Route 15 in Haymarket.

These multimodal improvements, which reflect extensive public input received at nearly 200 public meetings held since January 2014, are expected to move more people throughout the I-66 corridor, reduce hours of congestion per day, and reduce cut-through traffic on local roads. The preferred alternative consists of two express lanes alongside three regular lanes in each direction, with space in the median for future transit; dedicated express lanes access points; safety and operational improvements at key interchanges throughout the corridor; new transit services such as new and expanded park and ride lots and bus service; and corridor-wide bikeway, trail, and sidewalk improvements. Due to the cost and complexity of the proposed improvements, the board has approved a phased implementation approach.

Phase 1 extends the express lanes for 22 of the original 25 miles, from 495 to Gainesville, (University Boulevard), and then transitions to a traditional HOV lane in each direction. Phase 1 also proposes retaining existing ramps and bridges, and converting them to express lanes access points, at Monument Drive and Stringfellow Road, rather than rebuilding these interchanges.