>> 2. Only internal exhausts would be allowed which would be quite funny...
>>> then the driver has to inhale his/her's own pollution. This will make
>>> people quickly think about alternatives... like much cleaner cars and
>>> trucks and busses !
>>
>> I'd hate to see this idea extended to toilets!
>>
>>
> or breathing?
Breathing is carbon-neutral, assuming that your diet consists of animal and/or plant matter rather than crude oil and/or its products.