Glossary · 40 terms
The words in a commute report, defined plainly.
From median and 90th percentile to headway, GTFS and the four infrastructure statuses.
9
- 90th percentile trip
- The time that nine in ten sampled trips came in under. One trip in ten took longer. Imperibuild calls it the bad day trip.
A
- Average (mean)
- The sum of all trip times divided by the count. Not used on reports because one very long trip pulls it away from what most days feel like.
B
- Bad day trip
- Imperibuild's plain name for the 90th percentile trip time: the trip that makes you late.
C
- Claim type
- The category a commute claim falls into, such as minutes to a place, walking distance or upcoming metro.
- Commute claim
- A statement in an ad, brochure, hoarding or message about travel time, distance or proximity.
D
- Data principal
- Under the Digital Personal Data Protection Act, 2023, the person whose personal data is processed.
- Departure window
- The range of times you might leave, for example 8:15 to 9:15 am. Trips are sampled every 15 minutes inside it.
- Door to door
- The full trip from the home's gate to the destination's entrance, including walks, waits and parking.
F
- Feeder
- A short connecting service, such as a bus, shuttle or auto, between a station and a home or office.
- Field trip
- A trip made by a Imperibuild surveyor on the road or on transit, with a GPS log kept as evidence.
- First mile
- The leg from your home to the main road or station.
G
- Gate
- The entrance of a residential project that a trip starts from. Large projects have more than one, and reports confirm which.
- GPS trip log
- A timestamped record of positions along a surveyor's trip, used as evidence for field verified times.
- GTFS
- General Transit Feed Specification, a common format in which transit operators publish timetables and stops.
H
- Headway
- The published time between two trains or buses on the same route. Waiting time is taken as half the headway unless exact departures are published.
- Hour by hour curve
- A chart of typical and bad day times for each departure time in your window, showing when leaving earlier helps.
- Household hours per week
- The total time every member of a household spends commuting in a week, used in Shortlist Compare.
I
- Implementing agency
- The body building a metro line, road or station, such as a metro rail corporation or highway authority.
- Interchange
- A station where you change from one line or mode to another. Interchange walks are counted.
L
- Last mile
- The leg from the main road or station to your destination's entrance.
- Leg
- One part of a trip, such as gate to main road, the metro ride, or the walk from the station exit.
- Live sampling
- Querying a routing source at the actual departure time on each sampled day, rather than relying on a prediction.
M
- Median trip
- The middle trip time when all sampled trips are sorted. Half the trips were quicker and half were slower. Imperibuild calls it the typical trip.
- Method version
- The version of Imperibuild's methodology a report used, so anyone can check how it was measured.
O
- ODbL
- The Open Database Licence that OpenStreetMap data is published under. It requires attribution.
- Operational
- An infrastructure status meaning the line, station or road is open to the public.
P
- Proposed
- A status meaning the project is planned or under study, without final approval.
R
- Remeasurement
- Measuring the same trips again in a later period, for example after schools reopen or during the monsoon.
- RERA registration
- A project's registration with its state's real estate regulatory authority under the Real Estate (Regulation and Development) Act, 2016.
- Road distance
- The length of the route a vehicle actually drives.
- Routing source
- A licensed map service that estimates road trip times for a given departure time.
S
- Sampling
- Querying or making the same trip repeatedly at set departure times, to see how the time varies.
- Sanctioned
- A status meaning the project has been approved, with or without construction started.
- Station entrance
- A specific gate into a station. Large stations have several, and the nearest one may not be open or usable.
- Straight line distance
- The distance between two points as the crow flies. No road follows it.
T
- Traffic aware estimate
- A routing source's estimate of travel time that accounts for typical or live traffic at a given hour.
- Typical trip
- Imperibuild's plain name for the median trip time across the sampled working days.
U
- Under construction
- A status meaning work has started but the line, station or road is not open.
V
- Verification page
- A public page for a developer's project showing measured times, dates and method, which the developer cannot edit.
W
- Working day
- A weekday that is not a public holiday, bandh or declared disruption. Excluded days are listed on the report.