Dear Dr. Gridlock:

I’m a Girl Scout leader in Arlington, and we often take our group to D.C. for an event. The most recent was the Rock the Mall 100th anniversary Girl Scouts’ celebration. We buy paper Metro Farecards for the participants.

For occasional riders and a large group, it doesn’t seem equitable to pay such a large surcharge. We have a troop of 37 girls. That’s a lot of boxes of cookies to sell to cover the surcharge.

Is there going to be an exception for large group sales? The Paris Metro has a carnet where one buys 10 tickets at a discount. Perhaps they should stop charging for SmarTrip cards if that’s what they want everyone to use. You could buy one for $10 with that much already loaded on it.

— Ellen Smythe, Arlington

The $1 surcharge on paper farecards is Metro’s way of encouraging riders to switch to Smartrip cards. (Commuter Page)

The most frequently asked questions on the new Metro fares starting Sunday are about the $1 surcharge on trips taken with paper Farecards and on the types of rail passes available.

The surcharge is a policy move as well as a revenue-raiser. The transit authority’s intent is to push even more riders to give up paper and adopt plastic SmarTrip cards.

The impact will fall heavily on visitors and on groups traveling to events, as Smythe illustrates.

I also heard from several people who expect family members to visit this summer. They keep supplies of paper Farecards on hand to distribute to their arriving relatives. They collect the remnants when the guests leave. When they realized that each ride paid for with a paper card will now cost a dollar more, they weren’t sure how to adapt.

For them, I think the best policy now would be to buy a few SmarTrip cards, add the value of the old paper cards to them and hand the SmarTrips to the guests. Stash them in a drawer to distribute again when the relatives return for another visit. True, the cards cost $5 each, but they won’t go bad sitting in the drawer.

Metro won’t change the price, but in September, the transit authority will launch a rebate program. People who buy SmarTrip cards and register them online will get a $3 credit back to the card five days after its first use. That effectively cuts the cost to $2, though we’ll go through two big tourist months before the rebate system begins.

Among locals, whether scouts or club members or just friends who might travel into the District for a show or a museum visit, it would make sense for individual participants to own SmarTrip cards. Locals almost certainly would accumulate enough surcharge-free rides to cover the $5 investment.

If a visiting group plans just one round trip on Metro, for something like the Rock the Mall celebration, the options are very limited. There are no group discounts. A version of the Paris carnet would be difficult to price here, because the fare for our trips varies based on time and distance.

That visiting group probably would buy paper Farecards, pay the surcharge and aggressively market more Samoas and Thin Mints.

But suppose a person or group from out of town planned visits to multiple destinations in a single day. Perhaps they’d visit the National Zoo, the Capitol, the White House, the National Portrait Gallery and Arlington Cemetery.

Well, first of all, they’d be hungry and tired — even if they’re scouts. If they thought they’d have the stamina for all that, they could buy one-day passes online for $14 each. The new day passes no longer exclude travel during the morning rush.

If they plan to spread their visits over a few days, they could order short-trip rail passes for $35 each. These paper cards are good for seven days. During rush hours, the passes will be good for trips up to $3.50. Those are the short trips. At off-peak times, they’re good for any trip.

These passes aren’t necessarily bargains. Plan carefully and compare them to the cost of individual trips.

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