Day 227- Yes, There are Schedules
Believe it or not TriMet puts a heroic amount of time and effort into scheduling. It’s just the realities of driving in Portland often conspire to make said schedules less than accurate.
I don’t think I’m disclosing any juicy Agency secrets by saying there are many rules regarding schedules. On balance, and this is purely my take, the highest law regarding schedules is “never run early.” That rule consists of smaller details such as “never arrive at a time point1 more than 59 second early unless it is a transit center and never leave a time point early.” Obviously you don’t want to arrive and depart stops before published schedule arrival times since that results in customers seeing the backside of your bus heading down the road as they arrive at the stop hoping to catch a ride. This results, rightly, in customer rage.
All buses have GPS-enabled “copilot” devices tracking location and displaying, among other things, where the bus is in regards to the published schedule. On “frequent service2” routes buses are, ideally, 15 minutes apart, but one can see how a vast myriad of situations and events could impact sticking to such a schedule. This leads me to my first Q & A:
Chad from Boise asks: “Why does the scheduled bus never arrive at the time I want, requiring me to wait until the next arrival?”
This is a common question and I now have two weeks of experience with this very phenomenon. The reason is ebb and flow of customer demand will frequently cause a “leader” bus to run increasingly behind schedule. On a popular route any given day, Mondays in particular, a bus could have customers waiting at every stop. Loading customers takes time. This means the lead bus will fall more and more behind schedule and the “follower” bus, who is picking up only a fraction of the number of customers, will eventually catch the leader and, depending on road conditions, pass the leader. At this point the printed schedule pretty much goes out the window.
Now the new leader bus has “taken over” the schedule of the previous leader, but the new leader will now start picking up more passengers and will begin to slow down. Now neither bus is running on schedule. Customers waiting at stops, especially if they’re repeat customers who know the schedules by heart, will see the “later” bus coming down the road to pick them up, but the arrival time is confused because the “later” bus is arriving before its scheduled time, but after the “earlier” bus’ scheduled arrival time. On some routes “leader–follower” buses will leapfrog each other and, again depending on demand, drift closer to their actual scheduled arrival times by sharing customer load.
Then there is the addition of the “tripper” bus. “Trippers” are buses that deadhead to a start point somewhere along a route, drive portions of the route, then go out of service and return to the garage. Trippers are there to soak up excess demand along popular routes and prevent regular route buses from getting overloaded and being forced to pass waiting customers. Trippers can help, but in some cases trippers end up having an easy run because the leader is “doing all the work” and the tripper is just cruising along making the odd stop here and there.
Other factors often throwing a schedule into disarray are traffic combined with ill-timed traffic signals. Ever notice some days you just make all the lights and then other days you can’t seem to find a green signal out there? It’s not your imagination especially if you drive through downtown Portland. Losing a couple of minutes at five red lights in a row can easily put you 10 minutes behind schedule. Add in two customers with bicycles followed by a mobility device and suddenly your follower is blowing past you at the next service stop.
So while schedules are published and drivers do what they can to safely keep to them, the swarm of random events swirling around driving in a city like Portland can thwart even the best laid plans.
- “Time Points” are service stops along a route intended to help a driver stay on schedule. They are almost always major stops often where one or more routes intersect. I believe all Transit Centers are time points. ↩
- Frequent service in the TriMet universe means every 15 minutes or better and there are many frequent service routes ↩