In contrast, the addition of the bypass would make traffic in Central more responsive, because the east-west through traffic would be more willing to switch to the new route without passing through the busy Central area, which would help lower the optimal toll level of ERP.

Without the bypass, then, ERP could require so high an optimal toll level that it would become socially and politically unacceptable. Traffic congestion would continue to grow. If we really want to ease the traffic congestion in Central and its neighbouring network, we should consider the bypass and ERP as complementary rather than substitutable measures, and build the bypass now to buy time for the serious consideration of ERP. Only in this manner can we arrive at a more effective solution.

S. C. WONG, department of civil engineering, University of Hong Kong

Power sector opening

It is widely argued that the electricity market should open in 2008 and the permitted rate of return should be re-fixed to bring the tariff down. Whether it will come down is open to dispute.

To start with, there are cost components of the tariff that are unrelated to local inflation, the fuel and transmission costs. And the two power companies have to deduct huge amounts for depreciation, repairs and maintenance. So market liberalisation and lower rates of return may not cut tariffs a lot. Also, the two giants would not allow third-party access to their networks to compete for customers.

Thus, how can we open the market? The only way out seems to be for the government to acquire the network and rent it to power suppliers. But if politicians some day force the executive to charge suppliers a below-cost price to make the tariff cheap, is that the same as a public subsidy? Also, market opening is linked to interconnection with Guangdong. But the Pearl River Delta itself wants more electricity. Can it sell us power?

The permitted rate of return should go down moderately to provide a reasonable 'natural profit'. We must also provide other attractive incentives to keep the two power companies supplying electricity with consistently high standards of safety and reliability. So I suggest that they be permitted a special return - a certain percentage of 'net profit after tax' - after fulfilling safety and reliability standards.

TAM WAI-TING, Ap Lei Chau

Mother tongue for most

Peggy Leung ('English medium best,' May 11) cannot be faulted in her conviction that English-medium teaching is best for her child.

Her child goes to La Salle College, which has an excellent English-speaking environment and tradition, as well as teachers who can effectively teach academic subjects in English. But she should have no illusion that all schools in Hong Kong are like this.

Schools which do not have such attributes alas are in the majority. Ms Leung's assertion that 'greater exposure in English directly improves students' command of it without necessarily reducing their interest in other subjects' is not correct. If English-medium teaching is foisted upon classes, where the teachers are not capable of teaching effectively in English and the students do not have the aptitude to learn through a second language, students will be subject to the double jeopardy of not being able to learn good English and losing interest in other subjects. This has been proven in many studies, but is also plain common sense.

I do not see La Salle College being forced to abandon the English medium under the new policy. We should be worrying whether the bulk of students are learning effectively through the correct medium and getting the kind of education they deserve. The medium of instruction policy is an emotive issue because it necessarily classifies schools according to the ability of their teachers and students. That is perhaps why the government in its publicity only extols the virtue of mother-tongue teaching, without drawing attention to the fact - given that the top 30 per cent of students can learn equally well through Chinese or English - that we actually want them to stick to the English medium. This is because Hong Kong needs a tier of people who have a higher level of proficiency in English, as much as we need the remaining 70 per cent to be effectively educated in a normal standard of the language.

This optimum scenario can only be achieved through English-medium teaching for some, and Chinese medium with enhanced support for English learning for the others. If this involves a selection process, let's all face up to it.

YU KING-MUI, Mid-Levels

Who will bridge benefit?

In response to concerns that the bridge to Macau and Zhuhai will undoubtedly increase air pollution in Tung Chung (while destroying the North Lantau shoreline), the Environment, Transport and Works Bureau, which earlier was questioned by Legco on its effectiveness to combat air pollution, said 'it would mitigate any impact' on air pollution coming from the proposed structure.

This is comforting news, but how? And, more important, why is the bridge being built in the first place? Does Hong Kong need it? Or should it be built where Shenzhen needs it, to link both banks of the Pearl River?

Logistics industry experts have indicated that the accompanying planned logistics park is wrongly located, too far from any container terminal. And that Container Terminal 10 (CT10) does not make much economic sense, due to the under-capacity of the existing CT9, and the evolution of mainland logistics, which will adopt different patterns in another 10 to 15 years. In other words the bureau is envisaging future trends with past models.

So what benefits will the bridge bring to Hong Kong's economy? Is this project engineering-led, or demand-led? Let's face it, there is no demand for this bridge, which looks to be a waste of taxpayers' money. It will cause huge coastal degradation and pollution. It will be a boon for engineering companies, which will transfer the earnings overseas, leaving no return for Hong Kong, after pouring in tens of billions of dollars better spent elsewhere (like education). Is this a model for sound development policy?

CHRISTIAN MASSET, Clear The Air

MTR care on shops

We thank Candy Tam for her concern about retail outlets at MTR stations ('MTR hygiene woes,' May 4).

To provide customers with more enjoyable and convenient services, the corporation has developed a number of retail facilities at our stations. We have been very mindful in identifying their location and the trade mix. We have to seek approval of fire services, and station evacuation procedures.

All along, we have been striking a balance between providing convenient services to MTR passengers and safety as well as the security of railway services. Rest assured that under no circumstances will safety and security be compromised. We have laid down service standards, including cleanliness, to be observed by both ourselves and retail tenants.

MIRANDA LEUNG, general manager, corporate relations, MTR

No cannibalism

I do not wish to get involved with Peter Lok's anti-western diatribe ('Unselfish China,' May 12), but he is absolutely wrong about cannibalism on Ernest Shackleton's polar expeditions. One of Shackleton's boasts was that, unlike rival Robert Scott, he never lost a man on polar expeditions, even when he was stranded for two years. In fact, a lack of meat was never a problem. The stranded crew had an ample supply of penguins and other meat available - their great lack was sugar and carbohydrates. For recent credible evidence of cannibalism, Mr Lok should study Chairman Mao Zedong's 'Great leap forward'.

JOHN DUNN, Central