On time means 1 minute early to 5 minutes late.

The on-time window

Why early counts as a miss

If you arrive at your stop on time and the bus has already left, you wait for the next one. For a rider, a bus that comes early is worse than one that comes the same amount late.

How we work it out

1. We watch where each bus is. OC Transpo and STO publish live bus positions, and we keep every one we receive.
2. For each stop in the timetable we find where the bus’s path came closest to it. We read the time by working out how far between two positions the bus was when it reached that spot. A bus that waits at a stop is dated to the moment it first got there.
3. We compare that time with the timetable. From 1 minute early to 5 minutes late is on time. Earlier is early. Later is late.
4. We count the stops whose times the timetable fixes (timepoints). Times at other stops are the operator’s own estimates, so we leave them out.
5. Trips that never came count as misses. A trip the operator cancelled, and a trip we saw no bus on, each count against the share at every timepoint.
6. Anything we cannot judge is left out of the share, and we say how much. We never count it as on time or late.

What is left out, and why

• A bus we could not see well enough (the positions around its stop were too far apart in time) is not judged.
• A stop the bus never reached is a miss only when we saw the bus before and after it and the track was dense enough to be sure. Otherwise it is not judged.
• A drive-by is not a visit. If the bus comes close to a stop, the first time it does is the visit.
• A loop route is dated to its first pass. A bad position, such as a wild fix or one at 0,0, is checked against the ones around it and removed.

Limits, and how sure we are

Positions are the operator’s own, so a bus with its tracker off may look as if it did not come. Positions can be some seconds old. A time between two positions is an estimate, and every stop carries how far it could be out.

A bus that arrives early and waits for its time is judged by when it first reached the stop. That is how on time is defined here, so a bus held at a stop can read as early.

Confidence is high when many stops were judged and few were left out. It is medium when fewer were judged or more were left out. It is low when only a few were judged or many were left out. A low-confidence figure is shown hatched, with est. and a range. The same holds when a meaningful share could not be judged. The range runs from "none of those were on time" to "all of them were".

Where the numbers come from

• OC Transpo live vehicle positions
• STO live vehicle positions
• Published timetables, dated
• Rider sightings, kept separate

Method version and change log

A published month never changes. If a method is revised, past months keep the method they were worked out with.

• Version 1 · October 25, 2026. First published. On time is now judged from where each bus was, from 1 minute early to 5 minutes late. Trips that never came count as misses.