Bus reliability and Planning TIme

If you ask people what they want from public transport, they usually say "Speed." But if you look at behavioral data, speed isn't the most important factor. Reliability is. I would rather take a bus that takes 40 minutes guaranteed, than a car that takes 20 minutes but might take 60 if there is traffic. Uncertainty is stressful. Knowing "I will arrive at 8:55 AM" is worth more than "I might arrive at 8:30 AM". This is why dedicated lanes (BRT/Tram) are so powerful. They might not be fast, but they are predictable. We don't need to break the sound barrier. We just need to keep a promise. Do you prefer a fast gamble or a slow guarantee? - Juan Mora Triana

When my bus was scheduled to arrive at 7:55, I had to catch the bus scheduled to arrive at 7:40, because the second bus was late in picking me up. I worked in an office, being 5m late wasn't critical--but it earned me an unfriendly glance from my boss. And so, I started taking the earlier bus. And so, what was nominally a 23m trip (7m walk, 13m bus ride, 3m walk) started to eat 40 minutes out of my day. 

Making it worse was the irregularity in what was nominally a 15m bus. The 7:40 bus would be on-time, or early. The 7:55 bus would be 7-10 minutes late, reliably. So reliably that I began to time my walk from my house to the bus stop to start when the 7:55 bus was supposed to arrive, knowing that the bus wouldn't have arrived before I reached the bus stop. But that was for a bus I took five days a week. 

When I was trying to take a new bus to someplace new, I'd stroll up to the stop, pull its schedule out of my pack of pamphlets, use the system map to check which routes it serviced, pull out the appropriate schedule for the route, and check my watch. Then I'd take half the headway and estimate the blocks, figuring I could make 8 SLC blocks (~1 mile) in 20m, and that the bus moved about 3x that fast. For a 15m bus, I'd estimate a 10m wait (half the headway plus some uncertainty). For a 30m bus, I'd estimate I'd be waiting 20 minutes--the actual wait time plus what I could have walked waiting for the bus. For the hourly bus--I'd start walking. The combination of wait time plus uncertainty plus lost walking time made it a bad bet--my standard estimate was that I was better off walking two miles than waiting for an hourly bus. 

Even today, any trip under 10m, I walk. It's less stressful, because it's less uncertain. Even with a bus with a 15m headway, odds are I'll make it a half mile before the bus comes. I've repeatedly had the frustrating experience of seeing the bus I would have liked to take pass me by... but not often. 

Rapid transit, it's the same calculation, except that I remove the mental 'penalty' for potential to be late. The station will be nicer, there will be places to sit, there is an arrival time count-down [2] and I know the vehicle will be on time. Riding TRAX in SLC, if the train was 15m late, I'd tell me wife "Someone is probably dead" [1]. 

This also tied into my willingness to make transfers. My rules of thumb were that it was always worth it to transfer between a 15m bus and rapid transit, sometimes worthwhile to transfer between two 15m buses, and worthwhile to take a 30m bus TO rapid transit (but not the reverse). Anything else, I was better off walking. So I did a lot of things like taking TRAX west then south and then walking east from a Trax station, because it was a better bet than just waiting for a 30m bus to take me directly south. The bus would either be delayed in arriving or delayed enroute, where TRAX was practically a guarantee.

Admittedly, I was young and fit, with plenty of time to kill, and Salt Lake is a very safe city. But I also didn't have any other options: No car and lack of plowed sidewalks/lanes made biking in winter in SLC prohibitive. 

[1] After enough highly reported crashes at railroad gates, people quit racing the train, but someone racing the train at a red light stills seems like an annual event. SUV drivers are used to being the biggest thing on the road, but in a car-eat-car world, a train is an apex predator.

[2] Transit Information systems that only provide scheduled GTFS arrival times, rather than real-time GTFS data about vehicle location are a cruel joke, so knowable false that they can only be considered a deliberate deception.