Rush hour traffic is backed up along Interstate 66 in this view from the Vienna Metro station. (Photo by Nikki Kahn/The Washington Post)

Much of the public information campaign about the new Metro SafeTrack disruptions has focused on advising the transit users whose commutes will be directly affected. But most commuters drive, so they may not have considered the implications for their own weekday trips.

I’d like to tell the drivers that we know how the first of the special maintenance programs, between East Falls Church and Ballston in Northern Virginia, is going to affect highways and local streets at rush hours. The fact is we don’t. SafeTrack is not a formula for regional gridlock, because the 15 big disruptions for track work will be scattered around the region over the next 10 months. But transportation officials and travel experts have offered no specific guidance on how much extra delay each of the projects is likely to cause within particular areas.

In that regard, the drivers are in the same spot as the Metro riders. Metro officials tell riders to expect delays, but have not been able to tell a rider traveling from, let’s say, Reston to downtown Washington how much extra time to add for a Monday morning commute. But the Metro riders do at least have a lot of information now about the impact of the first maintenance surge on the Silver and Orange lines and about the transit alternatives.

While listening to just such a briefing at last week’s meeting of the Northern Virginia Transportation Commission, Matthew Letourneau, a commission member from Loudoun County, noted that  SafeTrack is not just about Metro riders. “All of us have to do a more effective job reaching out beyond Metro users,” he said.

So what can we tell drivers on the eve of the first commutes affected by the maintenance disruptions?

Researchers with the National Transportation Center at the University of Maryland have been doing some modeling. Their most recent results suggest that drivers should not see much of a difference in travel conditions. In the researchers’ simulations, overall travel delays in the affected zone increased by only 0.2 percent and the average travel speed decreased by just 0.1 percent. Travel time on Interstate 66 and the Capital Beltway increased less than 0.1 percent. They observed no significant increase in local traffic backups.

“Therefore,” the researchers said in a statement about the simulations, “drivers (or previous Metrorail riders who plan to drive, carpool, or take buses during the surge project period) should not worry about new gridlocks during this first SafeTrack surge project. Metrorail riders, however, should expect longer delays and significantly more crowding on trains.”

Besides modeling the traffic patterns, the researchers are surveying the anticipated changes in behavior among Metrorail riders. They estimate that 28 percent of them are planning to depart earlier than normal during the SafeTrack project. Crowding at stations in the affected area is likely before what are normally the peak travel periods. If crowding is a big concern, they suggest leaving much earlier than you normally would — perhaps an hour before the normal peak — or travel after the peak.

Now, this is just me taking their advice and trying to apply it to the Monday morning commute: Drivers may encounter an earlier than normal amount of traffic around the Wiehle-Reston East station at the west end of the Silver Line, and at stations between Vienna and East Falls Church on the Orange Line. I think many commuters who take Metro will stick with Metro, at least for the first weekday of SafeTrack, to see how that works out, before they consider some different option, such as a commuter bus, a carpool or VRE for Tuesday and beyond.

By the way, one option that makes no sense to me is for a commuter from the western suburbs to drive all the way in to Ballston in Arlington County to get beyond the single-tracking zone. That’s just too much hassling with local traffic congestion. Plus, the most direct route is on I-66, which is subject to the HOV2 rules inside the Beltway between 6:30 and 9 a.m. eastbound and 4 to 6:30 p.m. westbound.

The researchers say they will monitor what really happens with traffic during the weekday commutes, and so do officials with the Virginia Department of Transportation. Transportation officials need to be ready in case SafeTrack does create local traffic congestion. A VDOT statement said this: “For those who must drive, remain alert to increased congestion and prepare for extended rush hours, as commuters adjust routes and travel methods during each Metrorail line impact.”

The transportation department can use its Active Traffic Management system of lane controls on I-66 and also adjust signal timing on local routes for any major changes that develop in traffic patterns, such as an extended rush hour.

The VDOT managers will be eyeing particular routes that could be troublesome, and so should commuters: I-66 and the Beltway, the Dulles Toll Road; Routes 7, 29 and 50; Chain Bridge Road and Dolly Madison Boulevard, Georgetown Pike, Little River Turnpike, Columbia Pike, Baron Cameron Avenue; Braddock Road; Gallows Road; Sunset Hills Road; Wiehle Avenue and Sunrise Valley Drive.

Some of the Metro riders may opt for transit alternatives, but many will begin by driving to the locations where they can use those alternatives, such as express buses, carpools and VRE. That means drivers may encounter extra traffic near the Park & Ride lots and VRE stations in Fairfax County. The Fairfax County Department of Transportation said more than 4,000 spaces are available in the Park & Ride lots. It’s not just the potential for extra traffic volume. Some drivers will be using the lots for the first time, and they will be driving slowly, because they aren’t familiar with the access points.

VDOT said it will limit daytime lane closings for paving, maintenance, new construction and utility work along roads affected by any extra traffic.

Those commuters who drive all the way into the District should prepare for some changes in the traffic rules, based on concerns among the D.C. transportation officials about the potential for extra congestion.

The District Department of Transportation announced that starting Monday it will extend morning and evening rush hour parking restrictions by half an hour in some busy corridors. So the morning rush rules will begin at 7 and continue until 10 a.m. The evening rules will be in effect from 4 to 7 p.m. One of the goals is to keep the buses moving through extended rush hours on these routes.

During this first surge, DDOT is watching for extra traffic coming from and going back to Virginia, so watch for the extended rush hour restrictions along the routes that connect the Key Bridge to downtown Washington. DDOT said that includes M Street, Pennsylvania Avenue, Washington Circle, and H and I (Eye) streets, as well as adjacent streets. Drivers should see temporary signs notifying them about the extended parking restrictions.