Friday, 2 December 2016

Truck numbers - Don’t believe everything you are told

As we said below, working through Aggregate Industries' forthcoming planning application will be about separating fact from fiction. However, it looks like the misinformation has already started.

AI's leaflet told us that:
It is proposed to extract around 1.5 million tonnes of ‘as-dug’ sand and gravel over a period of about 10 to 12 years...
The material would be extracted at a rate between 120,000 tonnes and 180,000 tonnes per annum on a campaign basis which means that extraction would be limited typically to 2 or 3 times per year with each campaign lasting between five and seven weeks at a time.
People came away from the exhibition having been told that AI is planning 86 HGV movements a day (43 out 43 back).

Today's Ottery Herald:

reported that the proposal would "see up to 86 lorries a day using one of Ottery’s busiest roads" or "a ‘maximum’ of 86 deliveries a day during a campaign that would take place between March and November"; 86 deliveries would be 172 movements.

So, let's look at the numbers more closely:

Each truck employed would manage no more than 6 return trips per day, if each return trip took say 1.5 hours; 42 loads a day would therefore need 7 trucks; 84 movements over a 10 hour day would be one every 7 minutes. However, to clear the 1.5 million tonnes, 42 loads a day would require the absolute maximum duration that AI has proposed, i.e.:

28.5 tonnes per load × 42 loads a day × 5 days per week × 7 weeks per campaign × 3 campaigns per year × 12 years = 1.5 million tonnes

In other words, AI's '86 movements per day' would be at the minimum rate of extraction.

Conversely, the maximum rate of extraction would be over the minimum duration AI has proposed, i.e.:

1.5 million tones ÷ (28.5 tonnes per load × 5 days per week × 5 weeks per campaign × 2 campaigns per year × 10 years) = 105 loads per day

At the maximum rate of extraction there would therefore be 210 movements a day. This would require 18 trucks; 210 movements over a 10 hour day would be one every 3 minutes.

Say we look at something in between: 150,000 tonnes per year, extracted over 16 weeks, would need:

150,000 tonnes ÷ (28.5 tonnes per load × 6 loads per day × 5 days per week × 16 weeks) = 11 trucks

11 trucks would generate 11 × 6 × 2 = 132 movements per day, or one movement every 4.5 minutes.

Obviously, AI doesn’t yet know at what rate the material would need to be extracted. What is clear is that local people at the exhibition have already been misled by only being told the lowest number of movements per day that could be expected.

If the proposal for Straitgate Farm is so brilliant, so "strategically important and sustainable", why can’t AI have the decency to be straight with people?

Let's put AI's proposal in context:
Tarmac’s Aberthaw Cement Plant has opened a rail facility that will remove some 2,500 road truck movements each year as the company delivers on its pledge to support the sustainable delivery of materials and cut transport CO2
AI's plans for Straitgate, on the other hand, would result in:

1.5 million tones ÷ 28.5 tonnes per load = 52,632 loads × 2 = 105,264 movements ÷ 10-12 years = 8,772-10,526 movements per year

AI should be ashamed.