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Road wear calculations

With all the usual guff being spouted about 'road tax' I thought I would carry out a quick (back of a fag packet calculation) using the 4th power axle weight formula (see: https://en.wikipedia.org/wiki/Gross_axle_weight_rating). My calculations assume an average car weight of 1500Kg (including driver) with 50/50 split to each axle giving 750Kg, compared to an average bike weight of 90Kg (including rider) again with a 50/50 split to each axle giving 45Kg.

There is therefore at least a 16 times increase in axle weight (from 45 to 720Kg). From that I calculate that there is 65,536 (16 to the 4th power) times increase in road wear from a bike to a car.

Lets indulge the road tax half wits and say bikes pay £10 as long as road tax pays for road maintenance that makes car tax £65,536! My calculator would blow up for a lorry!

Could I ask all the mathematicians and engineers out there to check my workings. Is this correct-ish or have I made some school boy errors?

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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4 comments

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madcarew | 7 years ago
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Conversely, you can take the VED charge of (kind of randomly chosen) GBP130 / yr for a 1.3L car and charge a bike relative to that which is 0.19 p a year, so we could pay a 5 year sticker for 1 p ...

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ClubSmed | 7 years ago
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This is a very interesting calculation.

I have taken it a little further as some may argue that £10 is too much. The administration of Vehicle Excise Duty (VED) is £3.75 per vehicle (£127,689,000 collection costs of VED and 34,100,000 vehicles licensed for use on the roads in Great Britain 2009-2010) so it could not realistically be less than that. Even if they were looking for it to be cost neutral for bicycles though it would still make car tax £245,760.

Sources:

https://www.whatdotheyknow.com/request/36347/response/97782/attach/html/...
https://www.gov.uk/government/uploads/system/uploads/attachment_data/fil...

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Man of Lard | 7 years ago
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You sure did, taking the 16 ratio as reasonable - you've inadvertently given the car a 90% discount.  £10 x 65536 = £655,360 (I think this level of vehicle taxation may affect the economy slightly)

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Dropped replied to Man of Lard | 7 years ago
1 like

Man of Lard wrote:

You sure did, taking the 16 ratio as reasonable - you've inadvertently given the car a 90% discount.  £10 x 65536 = £655,360 (I think this level of vehicle taxation may affect the economy slightly)

And the prize goes to Man of Lard for spotting my error - thanks for that, it makes my calculation seem reasonable!

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