[ckissick]

I heard on the radio a couple years ago that car pool lanes cause traffic jams. The guest mentioned a city, maybe Baltimore (?) where they ended the carpool lane program because of the traffic jams. On the first Monday without the carpool lane, the traffic moved at the limit, and continues to do so.

If you a have 4 lanes and one is effectively closed to 95% of the traffic, opening that one lane increases capacity by 33%. That's a significant increase.