Coalition for Effective Transportation Alternatives

CETA
530 Dayton, No. 202
Edmonds, WA
98020
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Central Link Light Rail Initial Segment Safety Briefing

by John Niles

The physical design of the Central Link Light Rail Initial Segment right of way in conjunction with planned train headways (spacing between trains) and speeds presents potential safety hazards from collisions with motor vehicles in two sections:

(1) Within the Downtown Seattle Transit Tunnel (DSTT) where, during the busiest hours of weekdays in each of two directions, 10 trains are going to be operating interspersed with 60 buses. The mixture of trains and buses in a tunnel with station stops is not operated anywhere else in the world. Sound Transit designers are planning for the separation of vehicles to be maintained by a combination of a newly designed signaling system and the judgment of trained vehicle operators. At each end of the tunnel, buses will cross the tracks to enter the DSTT right of way.

(2) At 18 ungated grade level crossings along the median of Martin Luther King Jr Way in the Rainier Valley, 272 trains in two directions will be scheduled every weekday to cross the path of tens of thousands of motor vehicles, including cars, buses, and trucks. The 1999 Environmental Impact Statement for Central Link Light Rail revealed that 29 collisions between trains and vehicles per year would be expected, with some weak evidence that these collisions may not cause fatalities.

Federal Transit Administration safety guidelines published in the report Hazard Analysis Guidelines for Transit Projects (FTA-MA-26-5005-00-01 posted at http://transit-safety.volpe.dot.gov) require right of way designs to be certified for no more than one expected fatality per one million operating hours. For Central Link that many light rail operating hours will take approximately 20 years to be reached. Based on historical FTA light rail operating statistics, going 20 years with only one fatality from a collision in the DSTT or at a grade crossing will be a difficult standard to meet if Sound Transit tries to meet the train speed and headway performance requirements that have been established in planning documents.

If the Central Link design is not safety certified, I would expect that the six minute planned peak headways for the trains will not be possible because the light rail system design will be found not safe with this many trains moving at the required speed. The planned peak hour headways and associated speeds are the basis for the ridership forecasts that support the cost-effectiveness claims of this multi-billion dollar investment. If these headways are not possible, the entire New Starts justification for Federal funding support fails.

Although communications have been cordial and ongoing, the Federal Transit Administration has so far not responded definitively to the safety concerns described here, except to say that they believe FTA oversight of Sound Transit is sufficient. I am alarmed, however, that the Seattle light rail right of way design with ungated at-grade crossings in the Rainier Valley is apparently locked in before safety certification results have been released to the public.

With regard to the Downtown Seattle Transit Tunnel, we are somewhat reassured by a report that the USDOT Inspector General (in the USDOT Secretary's Office) as part of the Congressionally requested Central Link Light Rail Audit now underway has assigned a safety engineer to an examination of mixed bus and train operations in the Tunnel.