GCP on TV - Zone of contention

Dave Baigent from the Greater Cambridge Partnership (GCP) made an appearance on That’s Cambridge TV channel on 24 October.

The video says

Very, very, simply it’s about providing enough buses to get everybody through Cambridgeshire and the City from wherever they live to where ever they want to go. And that will be almost without exception, we will probably be covering everywhere. And if there is anywhere that isn’t covered then we’ll make sure that it is.
The thing about it is that there is no money for pay for it. So the GCP are going to put between £50m and £120m towards setting up the buses, and subsiding them for the first year or so. But after that there has got to be a way of paying for them. And the way of paying for them is through the Sustainable Travel Zone (STZ).
The fares are £1 if your in the city for every journey you make so thats from A to Z, and that includes changing buses. Or £2 if your coming in from outside the city. We are hoping that everybody who absolutly needs to bring a car part of the way can stop at the Park and Ride and then they can get a bus for £1. Those people that come in of course will pay £5 and that will be helping to subside the buses for those people who have chosen to use the bus instead of a car.

A simple and bold statement from the horse’s mouth, so to speak, a whole 79 seconds worth of information.
A reply to this is going to take slightly longer.

Let us break this down a little.

Very, very simply it’s about providing enough buses to get everybody through Cambridgeshire and the City from wherever they live to where ever they want to go. And that will be almost without exception, we will probably be covering everywhere. And if there is anywhere that isn’t covered then we’ll make sure that it is.

Very, very simply let us look at a given day from the Cambridge City Council’s traffic monitoring. This monitoring covers a single 12-hour day, from 0700 to 1900, in April 2021. The data is on the traffic monitoring website.

For simplicity, we will take the Elizabeth Way bridge. That connects a chunk of the City, and the chances are many of these journeys will be people going from “wherever they live to wherever they want to go”. Handily the Council survey breaks down the traffic by vehicle type too.

During this period, 27 buses passed the survey point. So let us assume they are full, and as the GCP says, a bus can take up to 75 cars off the road with a fully loaded double-decker bus.

We will assume buses are full; otherwise, we are not using them efficiently. Those 27 buses carry 2025 people from “wherever they live to wherever they want to go”.

Now let us look at the cars. A total of 17,167 passed during the same window. Let’s assume all the cars just had a driver, all very bad car drivers hogging the road.

To get 17,167 people onto buses requires 229 bus trips. If we spread this over the 12-hour window, that is 19 bus trips an hour. All is well and good so far. Now the GCP propose buses will run every 10 minutes, which is 6 an hour. So for a start, we need to ramp that up, or everyone will be waiting at the bus stops. We will need to cater for 25 bus trips an hour, don’t forget to add in the existing buses passing by. If the buses are not full, there will be even more bus trips needed.

But the GCP only want a 50% reduction in cars. So let us work that out, 17,167 divided by two is 8583 (rounded down) people. So now we only need 115 additional bus trips, or 10 an hour. That’s handy; we are looking for 10 an hour, all sorted. Ah, but we need to add in the existing 27, so that’s 142 or 12 an hour. So we need more buses again.

This assumes everyone is patient enough to spread their journeys evenly throughout the 12 hours. If there was, for example, a morning commuter period, it might be different.

For argument’s sake, let us say there is a rush hour, and it’s 3 hours long in the morning. Let’s also assume that we abide by the GCP aspirations and 50% move to the buses. But of those 8583 journeys, let us say only 30% are commuters travelling in the rush hour who need to move within that window. So only 2,575 people are commuting, and the remaining 6,008 are going about their daily lives outside the commuting period.

We now need to move only 2575 within a 3-hour window. That is 35 additional double-decker bus trips at just under 12 an hour. Roughly double the aspirational “every 10 mins” of 6 an hour proposed by the GCP. If these commuters had more than one person in the car, such as a parent and one or more children, you would need more buses. So, naturally, if the number of commuters is higher, let’s not go there.

It assumes there will be no bunching; you will all arrive equally spaced over the 3 hours and be ready to go. So you all get on where you need to and get off the same bus where you need to.

This modelling is exceedingly simplistic, hands up to that. Then again, so is the video above. It’s more akin to “I have a dream about buses as a solution, the only solution, there shall be many, many buses. We must identify a problem that many buses need to solve.”

If you can’t use a bus or even don’t want to use a bus, you are simply the problem. Nothing more.
Other road data is available; feel free to pick another route and do the maths.

One last thing on the above. All of this is based on all the buses being double-decker buses. The council have expressed concerns over a huge increase in double-decker buses in the city, which the GCP replied could be resolved with smaller buses. This means, more buses, as they carry fewer people.

Questions for the reader;

how often do you get on a nearly full bus?
Do you notice them busier at certain times of the day and quieter at other times?

Taking a quick peek at the charging;

The fares are £1 if you’re in the city for every journey you make so that’s from A to Z, and that includes changing buses.

Handling of the £1 all journeys including changing buses are still being worked on, as the “TECHNICAL NOTE: BUS PROPOSITION DESIGN SUMMARY PAPER” discusses.

Applying a £1 / £2 flat fare means that every time a passenger changes buses, they pay another fare. This could mean that for a journey involving multiple buses, passengers face payments as high or higher than they face now. There are two ways of mitigating this:

• A ‘hopper’ fare, as recently introduced in London, which allows the user to board as many buses or trams as required within one hour of touching in their payment card on a bus or tram. One issue is that some journey times in the Cambridge journey-to-work area are quite long, so this type of ticket may be of limited value for longer journeys such as those from Haverhill or Cambourne; or

• Periodic capping. This is a means of maintaining the concept of a discount for frequent use. For example, the London bus or tram daily cap is set at three times the single fare. We propose a structure along the lines of a £3.00 daily cap for journeys within the Cambridge Megarider zone and £5.00 for journeys outside or crossing the Cambridge Megarider zone.

In both options it looks like costs will be capped, but be more than the simplistic £1 including changing buses.