You know how there’s couponing and then there’s extreme couponing? Well, I’ve always prided myself on being not just a transit user, but an extreme transit user. In situations in which any sane person would just call a taxi or rent a car, I stubbornly look for some random bus that will get me close enough so my legs can carry me the rest of the way.

In 10 years of reporting around the D.C. area — and often way out into the burbs — this strategy never failed me. Until last week.

I needed to get to a location in Sterling, Va., which isn’t particularly close to our downtown D.C. office and is even farther from my home in Baltimore. So I wasn’t too surprised when I punched my destination into Metro’s Trip Planner and got the familiar response of “Unable to return an itinerary.”

That’s what Metro always says when there’s no service within a mile of your destination. But I am perfectly capable of walking more than a mile, so I was pleased to see that Google Maps (which now offers local transit directions) had a plan for me. It would take four hours and 20 minutes, but if I left early enough, I’d get to my appointment on time. Sold.

The first half of the journey went completely according to plan: MARC Train to Union Station, Metro to L’Enfant Plaza, Metrobus to Dulles Airport. That’s a long haul, but with my iPad, it was like being at the office. I sent off a slew of work emails, caught up on some blogs and planned my brother’s weekend visit.

I was still feeling pleased with myself when, as Google promised, the Dulles 2 Dulles Connector pulled up. For 50 cents, this mini-shuttle was supposed to whisk me to the Dulles 28 Centre, a shopping strip with a Wegmans and other suburban delights. And from there, it would be a 1.7-mile walk to my final destination.

As the bus arrived at my stop, I realized the walk part of this plan might be a problem. I managed to make it down Pacific Boulevard all right — there wasn’t a sidewalk, but the grassy strip to the side of the shopping center was plenty wide. At the turn onto VA-625W, however, I began to freak out. I started along the side of the road, hoping I’d soon spy a friendly cement strip that’d protect me from the many cars speeding by. Instead, I saw that the map wanted me to dash across three lanes of traffic.

So I did something extreme. I went back to Wegmans and called a cab. (And, miraculously, I managed to make my appointment.)

You might think that would have taught me my lesson. But on my ride home — after getting a lift to the Vienna Metro station — I realized that I could have walked north to the Washington & Old Dominion Trail to get across Route 28, which would have made the trek longer but totally doable. Maybe next time.