‘Private’ vehicles are subsidised too. You get a a road paved to where you’re going. You get maintenance, bridges, tunnels, intersections, signs, policing, courts, ambulances, fire trucks, lighting, parking (when free).
Cars are a massive transfer of public land to private usage. The cost of this needs to be factored in too.
Oh but you know it all change when a new lump comes in: a new office of collection must be created, temptation to use it to fund something else must be constantly fought, and 2 years later everyone even forgot why this tax was in in the first place.
The tax is nice to try, but what's best for laws like that is to remember they are trials, and we should be honest in accepting it's more expensive for everyone to pay a cheap tax than paying more for each transport, however weird it sounds at first.
