Emissions Testing; another reason to doubt the reports

A few weeks ago, I wrote about one of several buses that emitted clouds of smoke from places other than the tailpipe.  I noted observations about one particular bus and recalled that it was not an isolated occurrence.

In an interesting twist, at a recent MBTA Rider Oversight Committee meeting (which are open to the public), Eugene Benson of TRU-ACE gave a presentation in which he mentioned that the T has published the results of an emissions monitoring program online.  The test results themselves are stale and the most recent is from January 2009.  (Halfway is better than not-at-all, I guess.)  In addition, Eugene didn’t mention it, but in an unexpected twist, the diesel buses rarely fail their tests!  Sparkly clean!  Ten MBTA buses required repairs in the most recent six-month report, and only one diesel bus (#293) made the list.  Only the clean-fuel CNG buses required remedial work.  If you believe the reports, I suppose you might conclude that the clean-fuel buses are nastier than the diesels.  Who would have guessed?!?

But can you believe the reports?  Remember, the reports presumably were generated by the same MBTA mechanical supervisors that recently were dismissed for allegedly fudging their record-keeping.

MBTA emissions testing apparatus that fails to detect emissions from undercarriage  (click to see report)

Well, here’s another reason to doubt.  The MBTA included a diagram in its robust report explaining the emissions methodology.  The report explained that the T uses an elaborate visual detection system that scans the tailpipe on the roof of the bus.  When the emissions come out the tailpipe, the computer analyzes what is left and gives a result.  What happens when emissions come from the undercarriage and not the tailpipe?  Those emissions, dear reader, do not exist.  Poof!

Even the most credulous among us would have to admit that the detection system that is depicted will not determine whether the exhaust system on a bus is compromised and leaking.  And if the exhaust is leaking then the bus will not be flagged as having an emissions problem.  Wow.  That has to be a flaw that even an overworked, ethically flexible MBTA maintenance manager could appreciate.

It’s a leap to wonder whether, at the same time that T maintenance supervisors were revising mileage logs to avoid required servicing, were they also circumventing the emissions testing program by … simply allowing leaking exhaust systems to keep on leaking?  Discuss among yourselves.