How do you evaluate Metrobus performance?
Previously, I looked at WMATA's Metrobus performance data for 2007. Metro highlights the "worst performing" lines based on ridership and financial performance data. The criteria for good performance are:
- More than 300 passengers per day
- More than 10 passengers per trip
- More than 1.3 passengers per revenue mile
- High cost recovery ratio (>12.4%)
- Low subsidy per passenger (<$4.80)
In September, a Washington Post article by Lena Sun discussed WMATA's new ability to track bus on-time performance, and reported that WMATA has an overall system on-time performance of 75%. This figure is based on showing up at the published time points between 2 minutes early and 7 minutes late. Almost immediately after the article, I requested the on-time performance figure for each bus line in the system.
Based on the information reported (MS Excel file), the worst performing routes in terms of WMATA's ridership and financial criteria are better than average for on-time performance, probably because the routes operate in lower-density areas and don't have to slow down as often or as long to board or alight (drop off) passengers. On the other hand, WMATA's best performing routes have lower than average on-time performance, probably for the opposite reason: high traffic and congestion as well as ridership-driven delays due to boarding and alighting.
This brings up an interesting idea: How do you evaluate transit system performance? From the look of the WMATA productivity report, the only performance data highlighted is financial and ridership based. For a board that's is concerned with trying to ensure the region gets a reasonable bang for its subsidy buck, that makes sense. But for the ridership, is it really the best measurement of system performance?
Compare this to a transit system that is a leader in reporting performance data to its ridership: the Chicago Transit Authority. When CTA publishes its "dashboard"-style performance data for the system, they track six categories of system performance:
- What's the ridership?
- Is it on time?
- Is it efficient?
- Is it safe?
- Is it clean?
- Is it courteous?
Chicago publishes a monthly performance metric report, prominently linked from the home page. In the report, they state the performance goals and show the system performance for many months, highlighted in green when the goal was met, and in red when it was not. The report describes each item they measure, so you know what they're talking about. For example, one of the metrics is "% of bunched intervals, bus", which they define as "Number of weekday bus intervals (time between buses at a bus stop) that are 60 seconds or less divided by the total number of weekday bus intervals during the month." They have a goal of 2% or less, and it looks like they are not meeting it but with no strong trend up or down.
The Metrobus Performance Report appears to ask only one question: Does it carry a lot of passengers compared to how much we (WMATA) have to pay? That's a good question to ask for a system efficiency standpoint, but I think the riders of Metrobus deserve to have Chicago's five questions asked and reported too. I only have the Metrobus performance report and I do not know whether there are other reports out there that are as comprehensive as Chicago's. The Customer Service Operations and Safety Committee receives a monthly report on system on-time or reliability performance, and also a report on safety, but that report still does not delve more deeply into the on-time performance beyond WMATA's one top-line statistic. If there are better comprehensive reports, WMATA isn't presenting them to the board or posted for public consumption.
Here's the data. The first table is for the previously reported worst performing bus lines, and the second is for the best. The data covers the month of August 2008, which is from a different year than the 2007 Performance Report WMATA has released. I've been asking for the 2008 report for a couple of months through various channels and have not gotten a response.
There are a couple of bus lines missing from the reliability data because WMATA does not track on-time performance for them, and there are a couple of lines that are no longer operated so I can't make a direct comparison. Also, if you look at the Excel spreadsheet linked above, bus lines ending in "99" are employee shuttles not open to the public.
The "worsts" for ridership:
And the "bests" for ridership:
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