Commuters form slug lines on 14th Street NW near New York Avenue in this 2008 photo. Slugging is a very low-tech way of forming carpools to use the HOV lanes. (Jahi Chikwendiu — The Washington Post)

Dear Dr. Gridlock:

In these times of rising prices for toll road use, Metro transit, gasoline and parking, along with increasing road congestion, there is virtually no attention given to increasing use of carpools for commuters. One also sees many commuters driving to work alone.

I, an ex-commuter, realize that many people drive to work alone for good reasons, but others could benefit by joining carpools if they could more easily connect with riders living in close proximity who also work in closely defined employment sites.

Could not a clever IT entrepreneur devise a Web site and/or a cellphone app that could connect those potential carpoolers? There seem to be various applicable data sources, such as the Global Positioning System, ZIP codes, community associations and so on.

For example, such a system could connect workers living in closely defined residential areas in parts of Ashburn or Manassas who work at Federal Triangle or Tysons Corner. Cooperation by employers to offer reserved parking spots and some flexibility in working hours would help.

Who knows? If the clever entrepreneur can make this suggestion work in the Washington area, it would work in any city countrywide.

On the other hand, if this works, who is going to pay for the Silver Line?

Lester T. Jakobsson, Vienna

DG: There is an app for that. But for many years now, we’ve had a variety of resources — online and otherwise — available to people in the Washington region who want to share rides.

The key problem is that our commuters aren’t particularly social. Most of them drive alone. But any Metro rider can gauge the level of commuter sociability by standing in the middle of a rail car at rush hour and listening for the hum of conversation.

You don’t hear it, either?

Convincing Washington commuters that ride-sharing is pain-free and cost-effective has been a big challenge, but there are plenty of transportation services sponsored by governments and and entrepreneurs willing to try.

Some of the newest and most interesting efforts put commuters in the midst of online social networks. Such virtual communities have the potential to expand the attractions of ride-sharing.

Before getting jazzed about that, consider that our most successful carpooling story is very low-tech. It involves people showing up at parking areas along the Interstate 95 corridor and in the District and waiting for strangers to pull up. The drivers can then can pile enough people into their cars for a trip in the high-occupancy vehicle lanes.

This informal system of carpooling, famously known as slugging, seems to work just fine. But it has no equal in the region. That’s partly because the conditions along I-95 were particularly fertile: Traffic in the regular lanes is bad at peak periods, a carpool must have at least three people to be eligible for the HOV lanes and a lot of commuters are going to the same destinations.

I hope the opening of the 495 Express Lanes on the west side of the Capital Beltway in Virginia will create similar conditions for a carpool breakthrough. Drivers with at least two passengers can ride for free in them while others crawl along in the regular lanes.

But it remains to be seen whether technology will create a roadblock: The carpoolers need a new type of E-ZPass, called the Flex, to claim the free ride.

The interesting thing about the new Web sites and apps is that their appeal doesn’t depend on particular road configurations, or even on traffic congestion. A site such as Amovens (, to name just one in this category, invites travelers to register at no cost so that they become part of a ride-sharing community. The ride in question might be a morning commute from Frederick to Tysons, or it might be a Friday evening drive to Boston.

A driver can specify a price at which the driver is willing to sell seats for a trip. A passenger can offer an amount he is willing to pay for a seat. Most of the local trips posted are for less than $5.

Registration is partly a security measure for participants. But they can also rate drivers and passengers for the benefit of other registrants. This combination of financial incentive, security and social rating is typical of the new services.

But this is only the latest wave. The I-95 carpoolers, for example, have long had their own helpful Web site, It has message boards organized by topics and routes, a wealth of information to orient newcomers, a guide to slugging etiquette and a lost and found section.

Commuter Connections, a regional transportation program coordinated by the Metropolitan Washington Council of Governments, offers ride-matching services for carpools and vanpools at
commuter2. Arlington County Commuter Services’ Commuter, another helpful site, lists all sorts of ride-sharing and ride-matching services for the Washington region.