That is exactly how it works - more kms, more petrol and therefore more in excise tax that a car owner pays. However not all car owners need to enter congested areas like he CBD etc. Those who need to do so will have to pay ERP etc. So is structure in 3 ways
- pay COE when you purchase a car ( applies to all - general deterrent )
- pay more excise tax when you use the car more than others ( people will drive conservatively with more expensive fuel)
- pay to enter highly congested areas. ( some people leave their car and take the MRT to enter CBD)
If you have petrol excise tax alone, lots of people will have cars and they zip around their neighbourhood and it will be highly congested and soon the whole country congested like the CBD. So its a tiered approach.
One fits all policy has never worked in any country where needs and circumstances differ according to demographics and needs. Its easier for the authorities to implement one size fits all but it will not be fair on those who drive little and don't enter congested areas.
If the case, more you travel by road it fair that u shld pay more, do away with COE, ERP and lower the duty on import of cars and road tax, increase the prices on retail patrol to solve all the unhapoiness.