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On Autonomous Buses in Edinburgh
Nov. 15th, 2022 04:51 pmI am more interested in the impact of ground vehicle autonomy on public transport than is strictly speaking good for me, or, if you are reading this, you.
However, I've been mulling over the impact on Edinburgh's bus services of shifting to an autonomous fleet (which will happen any day now - they will be fusion powered).
Lothian buses are the main bus operator in Edinburgh with some other services being offered by another operator. Mostly those other services are routes coming in from the commuter belt not urban routes.
Lothian buses look to have about 60 routes.
Assume average frequency of every 20 minutes. 3 buses an hour. 4 hour round trip on each route is 12 buses per route. 720 buses operating each day. The Lothian buses web site says they have more than 700b buses so this seems like a reasonable set of assumptions in the round.
If you get a 1/3rd cost reduction you can increase the number of buses by 50%. If you assume an additional increase in revenue from ridership increase due to service frequency and additional routes you can add another 50% on top (maybe). So your 720 buses goes up by 150% times 150% to 1,620 (that seems pretty generous, but lets roll with it).
You could double the average frequency on all existing routes. Taking you from buses on average every 20 minutes to every 10 minutes. That's a nicer improvement than it sounds because the increase in service frequency disproportionately improves services on less frequent services. There are already some services at 10 minute frequency and more at 15 minute frequency. You do potentially start to have problems with congestion on the main routes in very centre of town. Lothian Road is already pretty close to being full of buses during rush hour. A model that fits these assumptions sees Lothian buses move from the majority of routes at 15 or 20 minute frequency to the majority at 10 minute frequency with a few at 5 minute frequency.
That is going to cost you another 720 buses - taking you to a total buses in use of 1,440 . That leaves you with about 180 buses spare to put on to new routes. With 6 buses per hour and a 4 hour round trip each new route would take 24 buses. So you get 7 maybe 8 new bus routes at a 10 minute frequency or 11 new routes at a 15 minute frequency.
Those buses could be running in theory 24 hours a day. Would you actually want to run a bus service with 5 minute frequency at 3am? Not sure you would but you certainly don't have a drop off in frequency in the evening and Sunday.
That is a pretty decent improvement in service but not quite enough to move to a fully metropolitan service which I define as one where buses are so frequent that you do not issue a timetable and travellers do not need to optimise their journey by picking alternative routes based on the exact time they are travelling. It's not far off though for small city like Edinburgh, especially if you consider that many journeys will have overlapping routes.
However, I've been mulling over the impact on Edinburgh's bus services of shifting to an autonomous fleet (which will happen any day now - they will be fusion powered).
Lothian buses are the main bus operator in Edinburgh with some other services being offered by another operator. Mostly those other services are routes coming in from the commuter belt not urban routes.
Lothian buses look to have about 60 routes.
Assume average frequency of every 20 minutes. 3 buses an hour. 4 hour round trip on each route is 12 buses per route. 720 buses operating each day. The Lothian buses web site says they have more than 700b buses so this seems like a reasonable set of assumptions in the round.
If you get a 1/3rd cost reduction you can increase the number of buses by 50%. If you assume an additional increase in revenue from ridership increase due to service frequency and additional routes you can add another 50% on top (maybe). So your 720 buses goes up by 150% times 150% to 1,620 (that seems pretty generous, but lets roll with it).
You could double the average frequency on all existing routes. Taking you from buses on average every 20 minutes to every 10 minutes. That's a nicer improvement than it sounds because the increase in service frequency disproportionately improves services on less frequent services. There are already some services at 10 minute frequency and more at 15 minute frequency. You do potentially start to have problems with congestion on the main routes in very centre of town. Lothian Road is already pretty close to being full of buses during rush hour. A model that fits these assumptions sees Lothian buses move from the majority of routes at 15 or 20 minute frequency to the majority at 10 minute frequency with a few at 5 minute frequency.
That is going to cost you another 720 buses - taking you to a total buses in use of 1,440 . That leaves you with about 180 buses spare to put on to new routes. With 6 buses per hour and a 4 hour round trip each new route would take 24 buses. So you get 7 maybe 8 new bus routes at a 10 minute frequency or 11 new routes at a 15 minute frequency.
Those buses could be running in theory 24 hours a day. Would you actually want to run a bus service with 5 minute frequency at 3am? Not sure you would but you certainly don't have a drop off in frequency in the evening and Sunday.
That is a pretty decent improvement in service but not quite enough to move to a fully metropolitan service which I define as one where buses are so frequent that you do not issue a timetable and travellers do not need to optimise their journey by picking alternative routes based on the exact time they are travelling. It's not far off though for small city like Edinburgh, especially if you consider that many journeys will have overlapping routes.
