With it, the corridor will continue to be traffic clogged. If you think the streetcar will reduce traffic on Columbia Pike, you’re sadly mistaken. The best case is that the number of cars will increase at a lower rate — the majority of people who will be moving into these new developments will not be “car free.” (If you think that’s not the case, then limit all new developments to provide one parking space for every two units and see if anyone complains.) Even if the majority were to use the trolley to commute, the number of vehicles will still increase — drivers will continue to use Columbia Pike from outside of Arlington.

You can say the streetcar will increase development — whether Columbia Pike should become another Clarendon is a different debate — but it will not decrease traffic.