UK Population Demand Curve
A population demand curve tuned on data for UK rail travel numbers.
TO USE AS YOUR DEFAULT POPULATION CURVE – a surprisingly complicated process:
1. Subscribe to the mod and enable it in a save
2. Open Company and Accounting > Options > Demand Curve Editor
3. Select the "UK Population Demand" curve and make a copy of it (button at bottom left, under the list of curves)
4. Select the copied curve and Info > Export to TSV File
5. Select the default "Population" and Info > Replace from TSV File, loading the file from step 4
Compared to the default curve, this curve has much stronger peak passenger flows. You will likely need to introduce peak-time services in order to meet demand, or have a lot of quite empty off-peak passenger services.
The curve also prefers to send passengers on shorter distance journeys compared to the default curve.
Known limitations of the curve are:
1. Rural passenger journeys seem too high, particularly short-distance ones where rail is uncompetitive with road.
2. Urban metro/underground journeys are too low.
3. Weekend passenger flows do not trend towards longer distance leisure travel.
4. Peak passenger flows are not direction-biased (towards city centres in the morning, away in the afternoon), and city centre stations receive too few passengers.
1 and 2 are limitations of NIMBY’s passenger routing model, which does not consider alternative modes of transport in the detail needed to distinguish rural and urban areas. NIMBY passengers don’t get annoyed by road congestion, and also are equally attracted to a single train every two hours as they are to a train every five minutes.
3 occurs as NIMBY does not let the distance curve vary as a function of time. I believe that all non-peak passenger flows should be a bit more heavily biased towards long distance travel.
4 could be rectified on conjunction with POI mods representing sources of employment, along with modifying the population curve to have lower Destination attractiveness during the morning peak.
This curve has been built based on the following data sources:
Rail Trends, Great Britain 2010/11, Rail Statistics Factsheet No. 1, Department of Transport. In particular, Chart 4, "Average surface rail trips in progress by time of day and day of week".
https://www.gov.uk/government/statistics/rail-trends-factsheet-great-britain-2010-11
National Travel Survey Statistics, tables NTS0501 ("Trips in progress by time of day and day of week"), NTS0502 ("Trip start time by trip purpose"), and NTS0504 ("Average number of trips by day of the week or month and purpose or main mode), Department for Transport.
https://www.gov.uk/government/statistical-data-sets/nts05-trips
Origin and Destination Matrix (ODM) 2022-23 [estimated annual passenger journeys between every station pair in Great Britain], Office of Rail and Road
https://raildata.org.uk/dashboard/dataProduct/P-a839de9f-eafa-495e-92e3-ff23a33ad876/dataFiles
BPLAN Geography Data [used to compute station pair distances – with some fixes for bad coordinates…], Network Rail
https://raildata.org.uk/dataProduct/P-03715cb3-22f2-48b6-94f6-bd88da9335f3/overview
