Will Sound Transit's Link system be safe?
With the ongoing debate of monorail versus light rail in Seattle, I think it's a good idea to discuss the safety of the Link Light Rail system Sound Transit is building. Monorail advocates often point out that monorail is by nature separated from pedestrian and street crossings (also called grade-separated), but I have also heard incorrect assertions that light rail is by nature at street level (or at-grade).
Light rail can be elevated, at-grade or underground - and Link uses all three. Downtown, it will use the existing transit tunnel - currently closed to have work done on the rails and overhead lines to support Link. On the way south to Beacon Hill, it crosses a few streets in south downtown Seattle and rises to elevated track. Beacon Hill is tunneled, after which Link is elevated for a station stop. Link then drops to street level through the Rainier Valley, before rising to elevated track again all the way to the airport.
In south downtown, the streets the light rail crosses already have other rail tracks crossing them. There has been track along the alignment the light rail is using since the 1880s - in fact, the rail is being laid in the same place that the first tracks into Seattle were! Drivers in the area are already used to train crossings, and there are few accidents. The crossings will also be signaled and gated to prevent drivers and pedestrians from crossing the tracks when there is a train passing.
In the Rainier Valley, Martin Luther King Jr. Way will have light rail directly on the surface. Area residents called for a tunnel through the region rather than a surface or elevated system because they feared that construction on the surface would run local shops out of business, but funding was not available to continue tunneling. It's widely believed that because the Rainier Valley is one of Seattle's poorest neighborhoods, their demands were considered secondary to those of wealthier residents in Capitol Hill and Montlake - areas which will be tunneled through.
With many at-grade pedestrian and vehicle crossings, this section will be prone to accidents - but not as many as people fear. TriMet's MAX light rail system in Portland has been involved in the deaths of only 18 people since it began operation in 1986 - an average of about one per year. This is impressively low, considering the MAX system is at-grade straight through high-traffic downtown Portland as well as Gresham, and as of 2004 the Yellow Line covers an equivalent distance and density to the MLK alignment. The MAX system served 91 million passenger trips between July 2003 and June 2004. With only one fatality during that time, that's almost as safe as flying. The equivalent car traffic would cause significantly more fatalities.
As an idealist, I would like to see rail systems always grade-separated (elevated or tunneled). Unfortunately, that's not always possible, either due to public preference in service areas or due to funding constraints. Considering the success of the at-grade sections of Portland's MAX system, I don't anticipate serious problems with the MLK section of the Link system - in fact, because many local drivers are already used to Tacoma Link, Amtrak Cascades and Sounder service, new crossings may not pose as much of a problem as they did in Portland when MAX service began.