On the Effect on Service Levels of Self Driving Buses

[danieldwilliam]

I am thinking about self-driving vehicles and the impact of them on day to day life. 

I am often on a bus from Chippenham to Calne so I’m using this bus route as the basis for some high-level* thinking about the impact on my life. 

I’m deliberately showing my workings in case** I have made a significant error in my assumptions. 

The service from Chippenham via Calne to Swindon that I use takes about 1 hour 5 minutes one way. It runs every 20 minutes from 6am until 10 pm. A 16 hour service. 

Labour Costs 

I think there will be 5 buses on the route at any one time, one way. Ten buses in total. 

Those buses will need drivers.  Ten drivers.  But they don’t work 16 hours. I reckon they work 8 hour shifts. So two shifts are needed for each day. That’s 15 drivers.   

The drivers will want holidays and will call in sick. I’m guessing about 15% additional headcount to cover absensce.  So that’s 17 and ¼  drivers working this route.  I estimate their salary including on-costs at £30k.  (I’m basing this on adverts I used to see in Swindon for bus drivers.) 

That’s a cost of £520k for direct labour driving the bus. 

Fuel Costs 

The journey is 22 miles one way. 

For three buses an hour each way for 16 hours I make that 96 trips of 22 miles or 2,112 miles per day.  The service doesn’t quite run every day but let’s assume it does.*** 365 days at 2,112 miles per day is 770,880 miles per year. 

Deisel fuel retails at £1.42.  Buses get a rebate of 43p on the fuel duty they pay so the real retail price of the fuel is closer to £0.99.**** 

Fuel costs therefore about £282k per annum. 

Total marginal direct cost for the service £800k  

So of the marginal direct costs 35% (ish) is fuel and 65% (ish) is labour. Shall we say a 3:2 ratio of labour to fuel. 

Sacking all the drivers saves £520k.  

If it helps let me point out that computer driven buses are going to be more fuel efficient than human driven buses.  I’m allowing for a 10% fuel saving, worth £28k. This takes the total cost of the service down to £254k or 32% of its original costs.  Pretty much the third of the cost. 

What conclusions do I draw from this? What is the impact? 

If you were to install a fleet of self-driving buses on the Chippenham to Swindon bus service and sacked all the drivers the savings from driver wages would be about the same the fuel costs for running the service, twice. Therefore you could either triple the frequency or run two equivalent service on a different route***** 

Self-driving buses half or better the cost, double or triple the frequency or double or triple the coverage of bus transport in the UK. 

There are some flaws with the analysis. The most significant is that in order to double the number of bus journeys you need to double or triple the number of buses.  Say £100k per bus. That would be £1.6 million for my Bath to Calne route. Or the savings made in drivers’ wage for 3 years. 

*EDITED*

*To update fuel cost figures for a fuel used per mile more reflective of rural driving conditions* Quite literally your mileage may vary for this post.

 

*Vague and almost certainly wrong but hopefully useful in a Fermi sense. Urban bus labour costs to fuel costs might be significantly different as urban buses are in stop start traffic and the density of buses per route is a bit higher (the routes are shorter and more frequent)

 

**In the expectation 

***The buses will have to be driven back and forwards to the depot and theirs driver training and so on. Let’s call it 365 days. 

**** There are other complexities to do with taxation, especialy VAT but unless you are the Tax manager at my last employer I won’t do VAT for you. 

***** A Bath to Calne route would be my favourite.

Comments

[danieldwilliam.livejournal.com]

I am sorry for the pain I have unwittingly caused you.

I think the important bit of data missing from your comment is how many routes stayed open that would otherwise have closed.

Hidden in this is the question of subsidy. How much subsidy were the buses attracting? How much of this subsidy was reduced and handed back to tax payers instead of spent on additional services? Difficult to tell.

We could see no more routes opened up but a big reduction in subsidy. Which would not be a bad thing but it wouldn’t be my favourite thing to do with the saving.

The issue of crowd control, anti-social behaviour and collection of fares is one to puzzle over.

Mind you, the survielance opportunities now available to bus companies coupled with the fact that if you are on a self-driving bus you have just stepped onto a moving prison might make serious anti-social behaviour less of a problem.

I think we would see wholesale replacement of buses. The savings from replacing a bus (and driver) mid way through its live with a self-driven bus are I think strongly NPV positive. Especially, if you can persuade / con some city in India to take the old buses off your hands for some money.

[f4f3.livejournal.com]

I can see the covers of those books now: "Six a Day", "Seven a Day" all the way up to "13 a day." And I usually had them finished before the end of the first term.

Yup, the routes staying open is interesting, but from observation routes closed anyway. The subsidy rules would need to be known - the minimum you have to do to collect your subsidy becomes the performance target.

Wider question is, why is their a subsidy? Especially if the subsidy is larger than the cost of the local authority providing the service.

And with buses as moving prisons, you've taken me into the realm of 2000AD, and Judge Dredd.

[danieldwilliam.livejournal.com]

I don't know what the levels of the subsidy are.

(other than the partial fuel duty relief).

I guess the subsidy is to cover the periods of the day when the cost of running an individual bus is greater than the revenues that that particular bus generates but where the bus is required to make the overall service worth having or to provide a social service for those without cars.

The subsidy from Edinburgh Council to Lothian buses looks to be about £1m on a turnover of about £112m. I think the situation in rural areas is much more weighted towards a subsidised service.

[f4f3.livejournal.com]

I don't think that the majority of day-time buses in Glasgow, at least, are not economically viable. So we either need to bin them, or admit that there are other, non-financial benefits.

[danieldwilliam.livejournal.com]

I think day time buses might be more viable then you think.

Certainly, they would be if you didn't have to pay for a driver.

Also, buses after mid-night - no driver, no anti-social working shift allowances.

[danieldwilliam.livejournal.com]

Judge Dredd is the future for rural bus services.

[f4f3.livejournal.com]

For every problem, there is a solution of the appropriate calibre.

[danieldwilliam.livejournal.com]

To change muscular law enforcement operatives...

This is a 44 seat ARIVA Hybrid auto-drive bus and seeing as it will revolutionise urban transport the question you got to ask yourself is, do I have an appropriate funding mechanism?

Well, do ya?