The Silver Line, which includes the McLean station shown here, will begin carrying passengers on July 26. (Bill O'Leary/The Washington Post)

Tom Biesiadny, director of Fairfax County’s Department of Transportation, is in the midst of one of the biggest transportation stories in the nation as the county prepares commuters to use Metro’s new Silver Line.

Biesiadny joined me for an online discussion to answer travelers’ questions about the new transit services. I selected these highlights.

Question: Is there actually a fear that the Silver Line will not be used by the amount of people predicted?

Answer: No. There is significant new growth coming to the Tysons and Reston areas, due to the arrival of Metrorail. We have heard from numerous sources that the new Metrorail stations improve the attractiveness for both areas to businesses interested in relocating to this region or expanding in this region, as well as people interested in living in these areas.

While we don’t expect Silver Line trains to be packed on the first weekday, there is significant anticipation in the community. I believe that ridership will meet or exceed expectations.

Q: Will there be any options from Herndon-Monroe Park and Ride to ride a bus directly to the facility at West Falls Church, or does Metro plan to just let that well-planned depot go to waste?

A: Taking the bus from the Herndon-Monroe Park-and-Ride to West Falls Church Metrorail station will no longer be an option. By turning all the bus service that currently serves West Falls Church back at Wiehle-Reston East, we can provide much more frequent bus service in the Reston-Herndon area, as well as more midday, late night and weekend bus service.

Dr. Gridlock: I get questions from readers about some long-ago decisions on the Tysons stations. Why were they not designed with parking garages? And why are there no kiss-and-rides at the Tysons Corner and Greensboro stations?

A: Tysons is anticipated to be a much more urban area, less focused on cars. The county’s Comprehensive Plan for Tysons envisions a more walkway, bikeway, transit-friendly environment with significantly higher densities. (You don’t find park-and-ride lots in downtown Washington).

In the short-term, there will be a private 700-space park-and-ride lot at the McLean station. At least two other property owners are interested in opening temporary park-and-ride lots this fall. There are kiss-and-ride lots at the Spring Hills and McLean stations, one on each side of Tysons.

We are also significantly increasing bus service from neighborhoods around Tysons and will implement three new circulator routes in Tysons with the opening of the Silver Line. Each will run on 10-minute headways in the peak period and every 15 minutes the rest of the day. You can look at the schedules for these routes at New bicycle and pedestrian connections have also been completed and more are being developed.

Q: I live in Crystal City and am wondering what shopping/dining/entertainment opportunities the Silver Line will open up for me. Will there be any type of connection between a Tysons stop and Wolf Trap? Is the Reston stop within walking distance of Reston Town Center and its restaurants?

A: The Tysons Corner Metrorail station is the closest stop to Tysons Corner Center and the Tysons Galleria. Both are within walking distance of the station. There is shopping and restaurants near the Greensboro and the Spring Hill stations, too. There is a movie theater in Tysons Corner Center.

For the 2014 season, the Fairfax Connector Route 480 will continue to operate from the West Falls Church Metrorail Station to Wolf Trap before and after shows. This may change for the 2015 season.

The Wiehle-Reston East station is about 1.5 miles from Reston Town Center; however, the Fairfax Connector will offer bus service every 10 minutes between them on Routes 505, 981 and RIBS 2.

Q: Can you please discuss the decision for the Silver Line to run through the Rosslyn tunnel, sacrificing capacity for Blue Line riders who board at Van Dorn Street or Franconia-Springfield?

A: The decision has a lot to do with the way the original Metrorail system was constructed. There is no “pocket track” (similar to the center track at Reagan National Airport or the one north of the Mount Vernon Square station that is used to turn Yellow Line trains) between East Falls Church and Rosslyn.

While it is possible to turn trains on the active tracks at Rosslyn, it would be very time-consuming and would result in significant delays. Beginning in the late 1980s, there were several alternative analyses that looked at which transit mode should be implemented in the Dulles corridor. The end result of those studies was Metrorail.

Dr. Gridlock also appears Thursday in Local Living. Comments and questions are welcome and may be used in a column, along with the writer’s name and home community. Write Dr. Gridlock at The Washington Post, 1150 15th St. NW, Washington, D.C. 20071, or e-mail .