I propose a more equitable system for the bidding and pricing of certificates of entitlement (COEs), to reflect the true necessity, utility and cost of car ownership, as well as to be a form of luxury tax.

All categories should be reclassified as follows:

Category A - Below 1,400cc

Category B - 1,401cc to 2,400cc

Category C - 2,401cc and above

Category D - Open

The minimum bid for Cat A should be fixed at $30,000 for the first six months of implementation and be reviewed every quarter thereafter.

The successful bid will automatically reflect and determine the adjusted prices of the other categories as follows:

Cat B: Automatically carries a 100 per cent premium, in addition to the successful bid for Cat A.

Cat C: Automatically carries a 200 per cent premium, in addition to the successful bid for Cat A.

Cat D: Automatically carries a 300 per cent premium, in addition to the successful bid for Cat A. (Most luxury and performance cars are registered under Cat D.)

Each household will be allowed to own a maximum of two cars. The third and subsequent cars registered with the same household address will be charged 200 per cent of the prescribed road tax.

This is a way to maximise car ownership within the same household and reduce land resources for carparks.

The Land Transport Authority should increase the number of COEs for cars below 1,400cc (Cat A), as this range of cars is deemed sufficient for the family and the average working man.

Furthermore, it should encourage more environmentally friendly cars for this category, to cut down carbon emissions in our high-density city state.

All others who need a car beyond basic transport purposes will pay a corresponding scale of premiums.

With this reclassification, all those who need a car for the family, business or work - such as those ferrying children or aged parents, those carrying out daily household chores, or sales, marketing or delivery personnel - will not be outbid by those who can afford to pay higher COE prices, if they choose smaller but less pollutive vehicles or a more practical car type/size.

In any case, more cars are reported to be left at home, which is an encouraging sign that our public transport system has improved significantly ("More leave cars at home to take trains, buses to work"; March 10).

This, in turn, means that it is time to fine-tune the COE system.

Sum Kam Weng