Thursday, May 25, 2017

Waiting For Transit

"Service frequency determines the average wait time for transit, and thus much of the overall travel time for a trip"

Q: Reallly? People spend that much time waiting for transit? 

A: Not average trip time, average wait time. Wait time, however, is a substantial portion of many transit trips, and the part of the trip people hate worst. The lit says that riders treat a minute of wait as the same as multiple minutes of in vehicle time. Many UTA buses (especially in Utah County) run at 20, 30 or 60 minute headways. Once you include the amount of time you have to wait when the bus is late, this can mean substantial waits. Given that people choose transit based largely on its time competitiveness to the automobile, this is a significant issue. It's most significant for short trips.  TRAX is frequent and (generally) reliable,. A 10 mile bus journey on a local bus is pretty miserable. WFRC likes to use 5-10 minutes for the wait, but I don't that that effectively reflects how miserable the experience is. It assumes people know where the bus stop is, how long it will take to walk there, and how long the wait will be. That is valid if you are taking the bus to work, once per day, but doesn't reflect the experience of using the bus for general transportation. The longer the headway, the higher the time-cost of missing a bus, so the more likely you are to leave your current location early to make sure your make it. If you have to use an (unreliable) bus connection to make that connection (such as bus to FrontRunner), there is even more waiting, because you can't control if you arrive 10 minutes early or 2 minutes too late, so you have to be 25 minutes early to be guaranteed a connection. Hence, I prefer to assume random arrival, at 1/2 headway, for any bus. This becomes increasingly important as UTA moves away from the '1-seat ride' model and toward the more efficient 'transfer network'.