To the members of the Tampa Bay Transportation Management Area Leadership group:Listen carefully when a new plan for a rapid bus system is unveiled to you on Friday. All the benefits the supporters will tout will undoubtedly be true.A rapid bus system will be cheaper than rail.It will be more flexible.It could be up and running much quicker.In fact, when all is said and done, the only possible drawback is this:Everything else.Pardon me if that sounds too negative. Honestly, itís not intended to be. At this point, I think the concept of bus rapid transit (or BRT, as it is commonly known) has greater potential than rail around here.But it has to be nearly flawless. It has to be approached as the best solution, and not a consolation prize. In other words, do not simply accept the recommendation because youíre tired of waiting for rail.Rapid bus systems have seen success in other countries and in some American cities, but they also have revealed some flaws in the system. So, while it may be more appealing to spend millions on buses instead of billions on rail, it will still be a waste of money if it isnít done right.For instance ÖIt must operate like a train. That means riders pay at the station, or on their phones, so when the bus stops, every door opens and riders have 10-12 seconds to hop on or off. No standing by the driver looking for coins or a bus pass while everyone else waits. This has been a problem in San Diego where some stations did not have a prepay option.For instance ÖExisting local routes cannot be robbed to pay for rapid routes catering to wealthier riders. Pittsburgh is currently dealing with this issue. The cost of providing a rapid line from the suburbs to downtown could mean eliminating routes for working-class people who depend on bus service.For instance ÖYou canít really call it a BRT line if doesnít have its own exclusive lane. If itís travelling behind cars, itís not really rapid. Itís just another bus. A Minneapolis line that had to exit the highway for a portion of its route was far less successful than a second line that more accurately mimicked light rail.For instance ÖThere must be a commitment to build new lanes, as opposed to repurposing existing traffic lanes. If reducing rush-hour congestion is a major consideration, then youíre probably defeating your purpose by eliminating one lane of traffic. Itís like a mathematical equation. If you have 10 cars per minute per lane, then a bus that uses a dedicated lane once every 10 minutes would theoretically have to carry more than 100 passengers to make up for a lost lane.As you can see, the philosophy of a cheaper, more fluid bus system can be appealing, but that doesnít mean it is either simple or guaranteed for success. Transportation leaders seem confident that they will be able to draw down money from both state and federal governments to get the project off the ground, but it will still have costs at the local level to build and operate. That means convincing residents/voters that this will work.And that means a plan with plenty of details and answers. That means convincing residents that they want to leave their cars behind for a slick-looking bus with comfortable seats, free Wi-Fi and a faster commute. That means providing many of the advantages of a subway without the construction cost.So, yes, itís worth giving Fridayís pitch plenty of time and attention.After all, it looks like weíve already missed the train.