Don't you just LOVE people who can calculate numbers? I do!

See why below, and then read the WHOLE article at the website given.

The Downtown Seattle Transit Tunnel Would Conversion to Light Rail Increase Capacity? Summary Sound Transit has released a document entitled "Downtown Seattle Transit Operations" dated 10/08/99. This document, which has been widely distributed to stakeholder groups, purports to show that light rail use of the downtown Seattle transit tunnel would have almost twice the capacity as bus. The document is wrong. One reason for this is that it assumes headways (time between trains) that are simply not credible. But the most glaring reason is that it compares bus operations under which no standing positions are taken, to rail operations under which they all are. Why the document assumes no standing passengers for bus operations we do not know and will leave for others to address. What a better analysis of the facts shows is that under all realistic scenarios, bus tunnel capacity is the same as or greater than rail.

---------------------------------------------------------------------- -- The 10/08 document and accompanying materials are predicated on 2 minute rail headways through the tunnel. Based on these headways as well as the assumption that every seat and every standing position in every train could be filled, the potential capacity of the tunnel is calculated to be 32,000 people per hour [1]. The document compares this with a stated bus capacity of 18,000 people per hour. However, these figures are erroneous. First, as noted above, in this comparison no standing positions are shown for buses --- an egregious, to say the least, oversight (assuming that it was an oversight). Taking into account standees increases the bus figure to 26,400 per hour [2]. Second, real world comparisons are even more favorable towards bus and less favorable to rail than this, since 2 minute rail headways are unrealistic. The Sound Transit Final EIS shows peak headways of 5 minutes. Using this number lowers the rail figure to 12,672 per hour [3] through the tunnel, less than half the bus figure. The fairest "apples to apples" comparison, using all-seated capacities, produces an even grimmer picture for rail vis a vis bus [4]: 6,912 vs 18,900.

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-- Craig Carson (craigcar@crosswinds.net), December 31, 1999