Tricycle? Tricycles? What, pray tell, is the problem that tricycles solve, Arlington County? Two wheels on a bike aren’t redundant enough? Can’t feel the wind in your hair on a Segway? Bethesda nab all the pogo sticks? I’d like to tell you that no one is judging you. You county employees who have registered in this trike share program are cutting down on emissions and proving that the suburbs can develop sufficiently dense commercial/residential corridors where you don’t need a car to survive. But I would ultimately be lying to you. If you are an adult riding a tricycle, it is the privilege — no, the obligation — of every one of your fellow human beings to point and snicker. Snidely, and with abandon. I urge you to save the planet and your dignity. Barring that, please promise that you will never, ever attempt to ride a tricycle in the District. The kids here greet adults riding bicycles by throwing rocks at them. There is no telling what they would do to a grownup on a trike.