One card per person, since you need to tap the SmarTrip to exit. New SmarTrips now cost $2 (and there's a $1 surcharge per trip to use a paper ticket, so the card pays for itself after 2 trips).

Thanks for the information. I believe the minimum one way ticket is $2.10. For a family of four, $16.80 minimum for a round trip seems hefty, plus the $8 initial cost. We are staying at the Rosslyn Holiday Inn so we'll probably do a combination of Metro and driving. We'll probably drive to the zoo, Teddy Roosevelt memorial, but take the Metro to the US Capitol. mall, and Arlington.

For Theodore Roosevelt Island, it probably makes sense to walk, since your hotel is so close to the Mt. Vernon trail entrance, and you'd otherwise have to drive in a giant loop since the only car access to the island from the NB lanes of the GW Parkway.

http://www.nps.gov/this/planyourvisit/directions.htm

Parking around the zoo is pretty tough. Allow lots of time and patience.

Note the $2.10 minimum fare is only rush hour (peak). It's $1.70 for shorter trips off-peak.

I've never had a problem with paring before in the zoo parking lot. Even the lot is an issue?

the zoo lot is huge and rarely fills up. I know because I drive by it all the time on Rock Creek Pky (Beach Drive at that point but no one uses that name. )

They do fill up on weekends, not sure about weekdays.

One thing to note, parking at the Zoo runs $22, so keep that in mind. If the family likes escalators Rosslyn is the 2nd longest in the system and Woodley Park (Zoo) is the 3rd longest.

If you take metro to the zoo, get off at Cleveland Park and walk south. Shorter and prettier walk, and not uphill. Trust me, I walk past Cleveland Park and the zoo and past Woodly at least 5 days a week.

The area near the Cleveland Park metro also has some decent lunch and dinner choices - certainly better than the choices near Woodly. It's an area free of conventioneers and tourists, catering to local residents.

I've rarely had problems getting parking along Connecticut Avenue....

Its a 10 to 15 minute drive from Rosslyn. Its 20 to 25 minutes on Metro (on the weekend).

Whenever you park in DC, pay close attention to the parking restrictions. They vary widely from spot to spot, metered or not. Some metered spots are free on weekends. Others only Sunday. Some may have two hour restrictions, sometimes only weekdays, sometimes not. Some are tow away during rush hours, and they DO tow. I see it all the time walking down Conn. Ave to work.

Sometimes the notices are on the meters. Sometimes nearby signs. Sometimes they don't agree. Save yourself a ticket or a tow by looking for the signs/notices.

One other bit of good news is that traffic cams are now all over - speed cams, red light cams and who knows what else. They do work and they do ticket. Red light cam is around $150 now, doubling if you don't pay within 30 days. It also seems like sometimes the first notice never comes, only the second at double cost. These fines will also follow out of staters home, so don't think your NY plate will save you. Finally, DC reportly has no "grace" speed. 31 in 30? they may get you. Maryland, OTOH, by law gives you 10 MPH.

So welcome to my city and have fun driving and parking!