The Virginia Department of Transportation has begun the overnight paving needed to finish the one-mile widening of westbound Interstate 66 between the Washington Boulevard on-ramp to the off-ramp to the Dulles Airport Access Highway.

This is the second of three short-distance widenings inside the Capital Beltway that are known collectively as the “spot improvements.” The first one, two miles between Fairfax Drive and Sycamore Street, was completed in December 2011.

Interstate widening projects inside the Beltway are a big political issue, but so is money. The Virginia government had to spread the cost of the spot improvements over many years. The third widening, between Lee Highway and Glebe Road, has not yet been fully funded.

These three widenings are somewhat separate from the debate over highway widening that accompanies the state’s proposal to create high-occupancy toll lanes at peak periods on I-66 inside the Beltway. Many people who live near the highway like this plan because it’s basically about managing traffic rather than creating more asphalt. But many long-distance commuters say they don’t understand why they should pay for a highway when they don’t get the benefit of more lanes.

The spot improvements program is much more modest. It basically involves extending merge lanes from interchange to interchange so that, for a short while, drivers wind up with an extra lane on the westbound side. The second spot improvement got underway in January 2014, at a cost of $33 million. While the project is modest compared to some other highway programs, the road work has annoyed drivers because of the necessary lane shifts.

This final phase of paving and lane striping is scheduled to take about three weeks, with crews working Sunday through Friday nights from 10 p.m. to 5 a.m. Watch for lane closings during that time period and anticipate delays.