The London Assembly Transport Committee recently held a Road User Charging public consultation between 9 February 2023 and 10 March 2023. Under these plans, drivers in London could be charged for every mile they drive. This anti-pollution measure is mile-based whereas emissions levels are kilometre-based.
I give you no prizes for guessing why drivers would be charged by the mile rather than by the kilometre. There can be no doubt that this is influenced by the use of miles for distances and speed and mile-based speedometers and odometers in cars manufactured for the British market.
It is a worthy goal to reduce pollution. This is what the congestion charge tries to do. When cars are sold, their emissions levels are expressed in grams per kilometre. The use of miles in this proposal is inconsistent with the use of kilometres in emissions levels. If you look at the measurements for the Ultra Low Emission Zone (ULEZ), they are all metric as well. You can find road signs showing you the number of yards or miles to ULEZ but all distances (and all other measurements) expressed in official ULEZ documentation are metric (e.g. see my recent ULEZ is all metric unlike UK road signs MV article). No miles are found in any official ULEZ documentation. This new proposal adds one extra dimension to the British measurement mess.
You can find the new proposals at:
Metric Views 
I read both references given in the article. The more authoritative of the two, issued by the London Assembly, wrote “the potential introduction of variable or distanced-based smarter road user charging” while carwow.com interpreted this statement as “Motorists in London could be charged for every mile they drive under plans being considered by the London Assembly (LA)”. Clearly the London Assembly are not committing themselves to what units of measure would be used.
If they go ahead, they have two different models that they can use. One is to charge motorists per unit distance travelled for example “6.3p/km (10.6p/mile)” or they would quote the distance that could be travelled per unit of currency for example “1p/159m (1p/174yds)”. Given that many HGV and bus odometers are in kilometres rather than miles, it would be imperative that TfL quote both.
The real problem as I see it is how to collect the data without infringing data protection rules.
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