In the posts I’ve written about the proposed Fall 2012 restructure, one complaint I’ve heard repeatedly is from Route 5 riders in Greenwood and points north, regarding diminished reliability and speed in exchanging Aurora for Dexter, due the attendant exposure to delays from the Fremont Bridge and Fremont traffic generally.
Fortunately, Metro collects data that can allow us to quantify the effects of this change, and I’ve assembled charts that will allow readers to do just that. There are two timepoint pairs involved:
- 3rd & Union to 34th & Fremont (and vice versa). This is the travel time of the 26/28 pair from Downtown Seattle to (and from) the heart of Fremont.
- 3rd & Pine to 38th & Fremont (and vice versa). This is the travel time of Route 5 from Downtown Seattle to (and from) its closest current stop to Fremont.
The additional travel time of about one minute between Union and Pine conveniently offsets the approximate travel time from 34th to 38th, so these charts provide an excellent travel time and reliability comparison between the current alignment of Route 5 and the proposed reroute to Dexter. Some points to bear in mind, when reading these charts:
- Express service on Greenwood and Shoreline via the Aurora bridge will operate during the peaks, in the form of either Route 5X or 355.
- The underlying data run from February through May, so neither the speed and reliability improvements from the Wall/Battery bus lanes, nor from the Dexter reconfiguration will be reflected in this data.
- Arguably the most precise timepoint comparison just to compare Aurora and Dexter would be from Aurora & Denny and Dexter & Denny to Fremont, but that data doesn’t exist (as far as I know). On the other hand, these two timepoint pairs most accurately characterize what riders experience under the current 5 versus the proposed revised 5.
Charts after the jump.
This chart shows travel times with error bars indicating the standard deviation of each travel time (more on that below). During the mornings and evenings, Aurora is about five minutes faster, widening to six or seven minutes during the peaks and midday. Between 17:00 and 18:00, reliability and travel times on both routes get spectacularly worse.
The same chart southbound. In the evenings, Dexter is only a couple of minutes slower, rising to about five minutes slower in the peaks, and roughly four minutes midday.
This chart shows just the standard deviation of the average northbound travel times. Standard deviation is a mathematical measure of how “spread out” a set of numbers are. In this context, it’s a little hard to define both accurately and simply, but the best I can think of is this: For a route with a standard deviation of (say) 2.5 minutes, the vast majority of buses will be no more than 2.5 minutes late. So the higher the number, the less reliable the route. Here we can see that, for most trips except in the early mornings and late at night, Dexter is about a minute less reliable.
This is the same chart southbound. The data here are suggest that Dexter and Aurora are similarly reliable heading southbound.
So, overall, Dexter is definitely slower and less reliable northbound, and a little slower southbound. Where you stand on this proposed reroute probably depends on where your stop is, but the discussion can now proceed in the presence of some facts.