Saturday, April 24, 2010

Things that matter: pedestrian safety

In a thread at on the value of speed in urban transit lines, commenter "dejv" remarked that crossing safety requires (among other things):
force people to look in direction of oncoming train by crossing design (those railings do that efficiently). I know about one death caused by screwing up these two details
 I don't know dejv, and he could have been referring to any number of accidents involving rail transit and pedestrians--but he could have been referring to a particular accident on Portland's MAX system some years ago.  There have been several accidents involving MAX and pedestrians (or private vehicles); and the vast majority were likely unavoidable by the agency.  Many involve suicides, intoxicated pedestrians, or trespassing on the line (by which I mean being on the tracks in places other than designated crossing); and of the remaining accidents that do occur at crossings, the human simply wasn't paying attention; and there's little that the driver or the system designers could have done.

The importance of visibility

But an accident at the Millikan Way MAX station, in Beaverton, was a different story.
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The Millikan Way park-and-ride is located near an office park in Beaverton (just to the northeast, out of the embedded picture, is the famous Nike Employee Store).  It's a side-boarding station, with two platforms (one for each direction), and the tracks in the middle.  A large parking lot is located to the north (as is the Howard Vollum industrial park), a small lot and a bus stop is located to the south.  Two pedestrian crossings of the tracks are located on either end of the platforms; two additional pedestrian crossings are provided for the sidewalks on SW 141st, just east of the station.

A few years after the westside MAX line opened (and I apologize for not having a more precise date--I wasn't able to track down any news reports of the incident, so this is from memory), a worker at a high-tech company located nearby approached the station on foot, from the north, intending to catch an eastbound train.  Upon arriving at the station, he noted that an eastbound train was already waiting, about to depart.  So the worker sprinted through the parking lot to the pedestrian crossing just east of the platform, and ran across the tracks there--and was struck and killed by a westbound train pulling into the station.  Crossing gates on 141st were active and included an audible signal; but it is easy to surmise that this was due to the eastbound train getting ready to depart.

One immediate thing to note is the presence of a pair of utility buildings, east of each platform, and immediately west of the street.  These were found to be contributing factors to the accident, as they both obscured the victims' view of the westbound tracks, and the westbound train driver's view of the crossing.  (The driver was not held to be at fault; as is the case in most train-pedestrian accidents; the train crew is powerless to avoid the collision). 

The solution, to prevent further accidents of this sort, was to install safety barriers at each pedestrian crossing of the tracks--spring-loaded metal gates which must be opened by anyone seeking to cross the traffics, in an attempt to ensure that they slow down--and hopefully check for oncoming trains.  In addition, mirrors were installed to improve visibility of the area behind the building.  Unfortunately for TriMet, not all stations were retro-fitted in this manner, and there have been similar accidents of this sort at other crossings.  Recently, an accident involving a pedestrian and a train at a sidewalk crossing near a station has prompted TriMet to go one step further and install gates (and pedestrian channeling) at a sidewalk crossing, a few miles west of Millikan Way.

An alternate approach

There are other ways to improve pedestrian safety on light rail or tram lines where pedestrians must cross the tracks.  The Ping Shan stop on the MTR Light Rail in Hong Kong serves as an illustration.

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There is nothing remarkable about this particular stop, other than it was close to where I stayed on a recent visit.  Many other LTR stops have a similar design, but there is one key attribute which is worth noting--the staggered platforms.

Like the Millikan Way stop above, the Ping Shan station is a side-platform design; with the passengers standing off to the side and the tracks in the middle.   However, the two passenger platforms (identifiable in the picture by the orange shelters), rather than being directly across from each other as was the case for Millikan Way.  The picture was taken from the westbound platform (which, in Hong Kong, is the southernmost one--trains, like traffic, move on the left in HK), and shows the eastbound platform.

A single pedestrian crossing, shown in the picture, is between the two platforms.  Accessing the westbound platform practically requires use of this crossing, as there is no safe street-level crossing of Castle Peak Road (the highway adjacent to the tracks) in the area--those wanting to cross Castle Peak use the footbridge shown in the background.

How does the staggered platform design improve safety?  For one thing, all pedestrian crossings of the tracks occur in one location, rather than in several, as is the case of Millikan Way.  More importantly, though, all pedestrian crossings occur in front of stopped trains (at least in normal operation).  The accident at Millikan occurred when the victim was struck by a moving train, one pulling into the station.  Trains which are stopped pose no danger, and those just starting out are less of a hazard then trains which are already breaking.

While some TriMet stops are space-constrianed, many on the westside Blue Line have ample room for staggered platforms.  Why the design was not considered, I have no idea.


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  3. I was referring to fatal accident at Prauge tram line to Barrandov at "Poliklinika Barrandov" stop (map). It's half of world away form Portland and details are slightly different (the view was blocked by wall, not house), but scenario was exactly the same: the 11 year old girl was running from north to catch NE-bound tram without slowing and SW-bound tram struck her while pulling to the stop. The problem was mitigated by installing this railing and an optical-acoustic warning system.

    The crossing design of Ping Shan station is called "zero speed crossing" over here and it's preferable to design stops like this whereever possible. This pic of mine shows nature of zero speed crossings fine, IMO.

    // comments deleted and reposted, due to combined idiocy by Blogger and Chrome

  4. Given that Blogger and Chrome are both from Google, you think they would work well together. :)

    It's interesting. The term "zero speed crossing", which I assume is a translation of a Czech term, doesn't appear to be used in English-speaking transit circles as far as I can find. (Google has zero hits that are relevant to transit). But I can't think of an English term for the design, especially one in layman use.

  5. It's informal term even in Czech.

    Note one more detail: the platform end is in some distance from the crossing to avoid people walking in blind spot right in front of the vehicle.

    Chromium bug 41467 and small textarea with limited space to resize and impossibility to edit posts are really nasty. Given the non-response of developers to comments #21 or #42, I'm starting to look for another browser.

  6. Another interesting safety factoid: in Russia, people were taught to cross the street behind a bus, but in front of a streetcar. Because if you cross behind a streetcar, there might be another streetcar on the other track, and the driver wouldn't be able to see you until you're already in its path.

  7. I believe many Yellow Line / Interstate MAX stations have the staggered platform design, don't they? I know Rosa Parks does, and I'm pretty sure Killingsworth does (from memory, I hardly get out of SE these days) as well. I wonder if that was motivated by safety concerns, or more by space issues with having to squeeze the line in the middle of the street?

  8. I find Firefox works well for me; though your mileage (or kilometrage) may vary.

    Arcady--I'm assuming that in Russia (or at least in a specific Russian city), streetcars run in the center lanes whereas busses run closer to the curb?

  9. Jay,

    There it is probably space issues--as Interstate MAX runs in the median, across the tracks from each platform is a left turn lane. And, separating the two patforms isn't just a pedestrian crossing, but an entire street crossing, including signalized crosswalks.

    Also note that at Rosa Parks, the station configuration is OPPOSITE of what is present at Ping Shan--rather than having a crossing between the exit tracks, the crossing is between the ENTRANCE tracks--were there not an intersection there, and instead just an unsignalled pedestrian crossing, it would be a highly dangerous configuration--as pedestrians would be crossing against moving trains in both directions, not against stopped ones. Given that the crossing is signalized, it's not a big deal, but the Rosa Parks design isn't the same.

    One difference between MAX and the Hong Kong LRT is that MAX trains are equipped with doors on both sides, whereas the HK system only has doors on the left. Thus MAX can use either center or side platforms, and many MAX stations use the center platform design, which has the advantage that pedestrians need only cross one track at a time.


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