Way before I swipe my SmarTrip to exit a Metro station, I know exactly how much that ride is going to cost. I never need to even think about the price of a Circulator trip: It’s always one buck. When I take a seat in a taxicab, however, I have only a vague notion of what my final tab is going to be.

Prepare to downgrade the accuracy of that notion further starting Saturday, when passengers will be hit with a quirky fare increase.

I think most folks are aware of the good news that D.C. cabs are finally installing credit-card readers. What I’m guessing most people have ignored — or couldn’t hear over the thunderous applause — is that the installation of the Modern Taximeter System comes at a price. That price is an extra 25 cents added to the current $3 flag drop rate and a $1 surcharge for anyone not traveling solo.

“That’s not fair,” you’re probably thinking. (Unless I’m just projecting.) But what would be really cruel would be making us pay more for riding in cabs that haven’t been upgraded yet. And on that point, the D.C. Taxicab Commission is on our side.

So here’s how the process is going to work. Between June 1 and Aug. 31, all taxi drivers need to have the new system installed. Until they get the new technology, they’re required to stick with the old price structure.

The setup gives drivers a financial incentive to get the upgrade. But for passengers who’d prefer to pay cash, it’s a reason to try to hail a cab that’s still on the old-school system.

You won’t know if you picked correctly until you take a seat and the driver starts the meter, says D.C. Taxicab Commission spokesman Neville Waters: “If it still says $3, [the taxi] hasn’t gone in yet for conversion.”

Waters expects that, at least at first, few customers will find themselves in cabs with the new system in place. There are 7,000 vehicles that need the upgrade and only about a dozen taximeter installation companies on the case, which should slow things down a bit.

And as eager as I am to live in a city whose taxis all take credit cards, I’ll probably be keeping my fingers crossed that I end up in a cash cab.

Uber Stays Put and Gains Competition

Relax, Uber-aholics! The company’s taxi-dispatch service is not being suspended come Saturday. After threatening to shut down June 1 in response to the new D.C. Taxicab Commission regulations, Uber announced that a last-minute modification has allowed it to put those plans in reverse. For now. That means it’s sticking around to face some more taxi-app competition. Hailo (Hailocab.com/dc), which dominates London’s black-cab scene, is inviting people to sign up as “founding passengers” in D.C. to get a $10 credit for when the service gets going. And some D.C. taxis are already using San Francisco’s Flywheel (Flywheel.com), which plans an official launch soon.