My March 31 report on the problems travelers face on Interstate 66, now the subject of a study by Virginia and federal officials, drew this response.

Dear Dr. Gridlock:

My heart sank when I read your article — not because I was surprised by the results of the study, but because I bet someone was paid to complete this when almost any one of the drivers on I-66 could have told you the problem just as precisely, except that we don’t know about 2040. We know about only today.

When people call for transportation improvements, they keep talking about public transportation. Obviously, having Metro from Warrenton and Gainesville to the District would make morning and evening commutes better, but what about weekends? Families going shopping or to soccer practice or sightseers from other states are going to use their cars, and many of these are not going all the way to the District.

This road needs improvements all along the way. Coordinating the lights at Route 234 and improving merge lanes would help but, in fact, we simply need more capacity. And I can explain it to anyone from out of town at no cost to the taxpayer.

Jean Lowe, Warrenton

DG: I know how commuters feel when they see these studies attempting to document the problems they are all too familiar with. Travelers react the same way when they see the national study that says the Washington region has the worst traffic in the nation.

Some are pleased to see their pain documented by researchers who use letter-grade measurements. (In the case of I-66, the letter is usually F.)

Most want to know what comes next. Is anything going to get better in their commuting lifetimes?The study — a Tier 1 Draft Environmental Impact Statement that probably isn’t something commuters would volunteer to work on at no cost — doesn’t spell out solutions in detail. The hard choices come later.

The draft does a fine job identifying problems, and one of them is the limited number of alternatives to driving alone. The Orange Line goes as far west as only Vienna and is set up to haul commuters to and from workplaces in Arlington County and the District. Off-peak service is “much less robust,” as the study puts it. There aren’t many north-south bus routes, and the corridor lacks biking and walking routes that would allow people to connect with other transportation services.

The researchers outline options for the corridor. Among them: Add regular travel lanes; add managed lanes, which would be subject to a variable toll; extend Metrorail; create light rail or bus rapid transit lines; and extend Virginia Railway Express.

No single approach is going to do the trick, the study says. Building extra lanes would not be enough, and extending Metrorail would not be enough. The peak demand will be so great that it’s best to focus on ideas that will move a lot of people within a limited space.

People who care about the future of the I-66 corridor have two big models to look at in their back yard: the new high-occupancy toll lanes on the Beltway, and the Silver Line, scheduled to extend Metrorail service by the end of the year. I think the performance of each will reinforce the notion that no single solution does it all.

There will be plenty of time to talk about the possibilities. A generation of Marylanders who have been following the glacial progress of the so-far-unfunded Purple Line through study after study understand the concept of government time.

Mobile aid

Dear Dr. Gridlock:

I was thrilled to read about the new Metro app for trip planning, iCommute DC. But despite your mention that it is available for Android, I cannot locate it in the Google Play store or the Metro Web site.

Susan Berger, Reston

DG: For Berger and other readers whom I might have mystified by mentioning the iCommute DC app and Metro’s new mobile Web site in the same column March 31, they're not the same thing.

The iCommute DC application for iPhones is a private product, available from NextBus Information Systems, that provides real-time Metro train and bus information, as well as information about some suburban bus systems and the D.C. Circulator. There’s a free Lite version and a $1.99 version with more features. They’re both available at the iTunes app store. The app is attractive, easy-to-use and helpful.

Much of the same information is now available for iPhones and Android devices through Metro’s own mobile Web site. That’s a transit authority product, recently upgraded. You don’t need to visit an online store to get it. Use your device’s browser to call up the Metro Web site, What you see will be the mobile site, which you can then add to your home screen.

I’ve been using both, and so far, I don’t have a favorite but do like the feature on Metro’s mobile site called “Service Nearby.” It uses your phone’s GPS to locate bus stops and show walking maps.