This is a time comparison of two different ways for getting from Ballard to downtown Seattle. The first is a fairly direct route, as proposed by SDOT. The second involves going from Ballard to the UW, then south, via the main line. As it turns out, not counting the transfer, the time difference is minor: roughly two minutes.
Generally speaking, trains spend a good part of their time stopped at a station or accelerating or decelerating. As luck would have it, both of these routes have exactly the same number of stops (eight inclusive). This simplifies things considerably. I also determined that the distance between each station is just big enough for the train to reach maximum speed (although in many cases, only for a second). Again, this simplifies things. Both trains would spend the same amount of time at a station or accelerating or decelerating. Thus the difference in time between the two routes is simply the difference in distance divided by the maximum speed. Based on my calculations, the SDOT route is 5.25 miles, while the route via the UW is 7.35 miles (a difference of 2.1 miles). Since the trains have a maximum speed of 58 MPH, going via the SDOT route saves 2 minutes and 10 second, not counting a transfer (if there is one).
The estimates are a bit rougher when it comes to the total time for either trip. I take two different approaches to figuring this out. Both lead to roughly the same amount of time: 18 minutes via the UW and 16 minutes via Queen Anne.
The first approach is to look at our system as it currently exists or is being built. Since stop spacing varies widely in our system, so too does the time it takes to travel eight stops. But I think we can start by ignoring the trips that include Rainier Beach to Tukwila, since that trip dwarfs the others in terms of stop spacing (over five miles). This gives us a range of 14 to 20 minutes. So, splitting the difference gives us 17 minutes. I think it is reasonable to assume that the SDOT route would take 16 minutes to get to downtown, while the route via the UW would take 18 minutes. This is roughly in line with other measurements. It is going to take 8 minutes to get from the U-District Station to Westlake, so it is reasonable to assume it will take 10 minutes from Ballard to the UW (the distance isn’t far, but there is an extra stop). This gives us 18 minutes via the UW and 16 minutes via Queen Anne.
The other approach is take the estimates that Sound Transit gave with the studies. Sound Transit did not include a time estimate for a Ballard to downtown route like the one that SDOT proposed. The closest route that resembles it is Corridor A, which gives an estimate of 14-19 minutes. The SDOT route adds two stops, so it is reasonable to take the far end of that proposal, or 19 minutes.
Of the various proposals for UW to Ballard high capacity transit, only one involves a light rail in a tunnel: A3. The time estimate for A3 is 6-9 minutes . However, there are only two proposed stops with that route. With the addition of two more stops, I think we can take the high end of that estimate: 9 minutes. Once you add the known time (8 minutes from the UW to Westlake) you get to 17 minutes. Using this approach gets us within a minute of the other estimate (17-19 versus 16-18).
Given the imprecise data surrounding actual travel time, it is not known exactly how long it will take to get from one place to another. However, based on the distances, the number of stops and the capability of our trains, the difference between the two routes will be around two minutes.