Annex B - Technical discussion of the data in indicator 3A
This section emphasises the necessary caveats for interpreted the journey time data.
Caveats for Regarding Journey Time Calculations
Several caveats need to be emphasised in the context of the journey times data.
In the first instance, while the analysis measures the fastest available journey, the analysis does not say anything about how frequently journeys can be made within these time periods. This is to say, it might be the case that, within the time parameters, there is only one journey available from a given data zone to the location in question within the given period. This journey will be returned by the analysis and indicate that the route is available within the available timeframe, but this will not reflect the limited accessibility that results from infrequent journeys.
Second, the model calculates the fastest available route. This should be distinguished from the average journey time, or the journey time available to participants from any starting period. For example, if a given shortest journey time is 11 minutes, this does not mean that an individual could travel to the given destination within 11 minutes at any point from the PWC of the data zone, but simply that there is a journey that lasts that long that is available.
Third, the model calculates the nearest location that fits the description of the essential service in question. This means that, for example, it might be the case that a data zone can access the nearest hospital within an acceptable time period but, in practice, the nearest hospital service for an individual lacks capacity to provide particular services required by that individual in that data zone. Therefore, caution should be taken when making extrapolations from these results.
Finally, the locations chosen in this first iteration do not exhaust the list of essential services that an individual may need to access. As this is the first time this analysis has been attempted, a short list of services concerned with health, access to other transport modes, education and food was selected for analysis. However, as this analysis develops over time and is repeated in the future, further locations will be added through ongoing consultation and discussion with stakeholders.
Data Sources
Public transport timetable data was downloaded from Basemap Datacutter service, which provides quarterly ‘snapshots’ of UK public transport timetables for use in software such as TRACC. The data is collected from Traveline National Dataset (TNDS) and Association of Train Operating Companies (ATOC) as well as NAPTAN stop references.
The public transport timetable data obtained for this task was 2020 Q1 – representing the 2nd week January 2020 – and covers the extents of Scotland. This is the last available public transport network dataset pre Covid-19 pandemic. The modes available and used in the calculations are:
- Bus
- Coach
- National Rail
- Tram (this refers to both Edinburgh Trams and Glasgow Subway); and
- Ferry
Scheduled air services are not included in the timetable dataset. As for the location data, these were sourced in the following ways:
- GP - NHS Open Data
- Hospitals - Information Services Division (ISD)
- Primary School - ‘Scottish School Roll and Locations’ (2021)
- Secondary School - ‘Scottish School Roll and Locations’ (2021)
- Further Education - Universities Scotland, Colleges Scotland, and UCAS.
- Higher Education - Universities Scotland, Colleges Scotland, and UCAS.
- Food Outlets - GEOLYTIX Retail Points (2018)
- Train stations - All National Rail train stations as at February 2022
- Airports - Main commercial airports: Aberdeen, Edinburgh, Glasgow, Glasgow Prestwick and Inverness.