Thursday, July 29, 2010

Lesson from Pittsburgh: How NOT To Color-Code Your System

Recently I was in Pittsburgh to see my family for a few weeks. Now, my family is currently living in the neighborhood of Beechview, which lies just within the southern reaches of the Pittsburgh city limits and is served by the regional light rail system called the "T".

As modern light rail systems go, the T is pretty old. These are gray vehicles from the late 80s, running on less-than-stellar track (the train often squeaks loudly). The in-traffic operation is similar to San Francisco's Muni Metro: the trains operate in a subway in downtown, then emerge and run in a mix of dedicated track way or mixed traffic with cars, with low platform stops in the middle of the street. Also similar to the Muni Metro, the entire system (save for the subway tunnel) is running on the remnants of a much older streetcar network.

Now in terms of operation, the trains operate basically like a very big bus - the fares and the fare collection system is pretty much the same as the local buses (save for a few "raised platform stops", which have fare booth attendants - NOT machines) and it serves mostly the same clientele as the bus system. And until recently, it had numbered routes, like the bus system:

(Ignore the "44L" line - the one in lime green. This is an old map and that one was disbanded long ago.)

Basically, the light rail system is two main lines which head south from Downtown - one which goes through Beechview, the other through Overbrook. From these, there are a few branch lines - the 52 line (marked in orange on the map above) which goes through a neighborhood near Downtown (this one only runs during rush hour), a branch to the South Hills Village mall, and the line south to the suburb of Library. The 42C and 42S lines cover the same ground, with the 42S going further because of the limited demand at the southern end of the line. The 47L and 47S lines cover mostly the same ground, with one line going to Library (again, limited demand) and the other going to South Hills Village with the 42S, to connect the area to the residents of Overbrook.

It's not the simplest system in the world, but once you understand it you know where each route goes.

Then, as part of a recent "restructuring" of the system, spurred due to budget cuts, Pittsburgh adopted a color-coded system for their light rail network. I don't have an image of it, so I'll link to the PDF route map they have on the website.

Take a look at that map. The 42C and 42S has been replaced by one line, the "Red Line". The 47L and 47S are now the "Blue Line". The 52 is now the "Brown Line". Simple, right?

But now scroll to the bottom of the map. The Red Line apparently has limited service to South Hills Village. So some of the trains go to South Hills Village...but not all of them. And the Blue Line inexplainably splits, with some trains going to South Hills Village and some to Library...but which ones go where? Whereas before we had a numbered route and I knew where that route went, because it went there every single time, now we have a line which doesn't always wind up in the same place every time.

Obviously, there was no "restructuring" of the system. These are the exact same routes we had before, but now in harder to understand form. And that's what irks me about this so much - the whole point of color-coding a system is to make it EASIER to understand. Not harder.

1 comment:

abqdave said...

The Red Line makes sense to me; when heading south from downtown, you can use any train to get to any stop in the solid red area, but will have to switch trains at Overbrook Junction to go any further. If you get on a train that stops at OJ, but wanted to go to SHV, the worst that can happen is you have to switch to the SHV train at OJ. Since you would have had to wait for that same SHV train downtown to get to SHV anyway, there is no disadvantage to the rider, and no reason for the rider to worry about which train to get on downtown.

The Blue Line is the problem; you can get on a train that will bring you to a wrong destination. In the past they used two different number/letters 47L and 47S, but since they are now using colors, they need to use two different colors.

The Green Line in Boston is another bad example of this; it branches into 4 different lines past downtown. Get on the wrong train, and you can be 10 miles from your destination.

I think the rule should be; if you are using colors, and different trains on a shared line can bring the rider to a wrong destination (as opposed to bringing the rider to a stop short of the final destination but where another train will come along later and bring the rider to that final destination) the line needs to be a different color.

It is interesting that naming a route a color almost universally means it is a high capacity/frequency limited stop service, whether a subway/light rail in Pittsburgh or ABQ's Rapid Ride service.

If I were the King of Transit Planning...I would use colors for high capacity/frequency liimited stop service, but use only one color for the whole system. The point is...that color would always and ONLY mean high frequency with limited stops. Use numbers for the different high frequency limited stop routes similar to the interstate highway numbering convention. Other colors would mean something else; brown might be high frequency local routes. Blue would mean low frequency local routes. Pink would mean commuter routes.

Having more than 4 or 5 colors on a system map makes it incomprehensible. The rider generally wants to know...will the service be there when I want it (frequency), and what is the fastest way to get there (local or limited stop).