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]

Over crowding – or to give it its proper economics name – a queue - is a symptom of too much demand meeting too little supply. Solutions, raise supply or reduce demand.

Raising supply might be difficult where the marginal cost of additional supply is greater than the marginal revenue from additional journeys. In railway engineering terms I can see that this might be the case on parts of the UK rail network where significant capital costs (which are hard to divide) are required.

The other solution is to reduce demand. This can be done by providing substitutes or by raising the price. Substitutes suffer the some of the same infrastructure provision issues, depends how you do them. (I’d vote for self-driving buses). Raising the price is easy. Not so good if you are a punter.

Buses I think suffer from this problem less so.

For the price of a dozen buses I could start a Bath to Calne bus service. I don’t need to spent millions upgrading stations or laying track or upgrading signalling.

[f4f3.livejournal.com]

I think we're getting into the area of public transport as a social good. There are so many virtuous circles possible, where more trains mean more people take the trains, where lower fares bring in more passengers, which drops the number of car journeys, which drops pollution and demand for fuel, and also lowers stress, which is a societal good, and, and, and...

But this is systems thinking. Buses are for making money, and a bus service can only be viable if it is profitable. Even with the financial subsidies given, service provision is drawn towards the minimum standard which still gets your subsidy paid.

In ye olden days of the 1970s and 80s, Glasgow had an integrated transport policy covering trains, subway, buses and even the odd ferry or two. That was broken up in the 80's in the interest of lessening council powers.

I wonder how that worked out?

[danieldwilliam.livejournal.com]

There are virtual externalities that are difficult to capture in the ticket price.

One might suggest a funding model where indivual passengers pay what the service is worth to them through a ticket and society as a whole, through local authorities, pay what a good bus service is worth to society as a whole.

I think those funding arrangements look similar to the current funding arrangements.

Again, I think one is stumbling into the seductive power of the Thatcherite mindset when considering bus routes individually, or bus services on their own.

However, I'm unclear how else to tell if a bus service (route or in toto) is valuable to local citizens without using a ticket price (in the absence of more direct democracy0.

[f4f3.livejournal.com]

"However, I'm unclear how else to tell if a bus service (route or in toto) is valuable to local citizens without using a ticket price (in the absence of more direct democracy."

Journeys are already unmetered for pensioners - maybe they should be unmetered for all, and funded directly from taxation.

[danieldwilliam.livejournal.com]

Maybe.

But how to tell if the service provided is the one most wanted? Or if service that is little used by members of a community is actually really valued by them because it means that the dozen pensioners and the dozen teenagers in their village have access to the wider world without needing a lift from mum?

Actually, this raises an interesting point about self-driving cars.

If I'm not driving, do I need a license? If BB at 14 isn't driving does she need a license? Could she just hope in the car and tell it to take her to Nando's.

What about the Capt? Could I pop him in the car, send it to Grandad's and have Granddad meet it in his garage?

[danieldwilliam.livejournal.com]

I'm all in favour of increasing council powers.

So long as increased council powers are matched by increased voter power.

I wouldn't want to make public transport the sole preserve of local council though. I think the ability of a aggrieved and enterprising locals to say "You know what, I could do better than these monkeys, and I will."

For example Free Bus in Bristol.

http://www.freebus.org.uk/

[f4f3.livejournal.com]

And also Stagecoach, which started as a single run from Glasgow to Inverness, winning huge market share with such innovations as tea, sandwiches, and a toilet for the 5 hour journey.

[danieldwilliam.livejournal.com]

and ended as Stagecoach.

I'm cautious unfettered power in monolithic organisations. When they are privately owned I want the state to be able to step in with regulation or competition.

When they are state owned I want the ability for the private sector to sidestep the state.

Mainly, I want the ability for people to vote with their feet if the service they are getting isn't what they need.

[danieldwilliam.livejournal.com]

One of the things I like most about the model I'm building up in my head of driverless buses roaming the countryside and suburbs is how democratic that makes things.

Poor, can't afford a car? Or are you visually impared, epileptic or born with wrists too weak to steer?

Don't worry, there will be a bus along in a few minutes that will take you to the library, the shops, your local MSP's office, your community group or sports club.