It was reported that a 72-year-old taxi driver lost consciousness when a previously undiagnosed tumour in his liver ruptured while he was driving, resulting in a serious accident and one death (Ruptured liver tumour caused cabby to black out, Sept 20).

It appears to me that many - if not most - taxi drivers are middle-aged or elderly, and perhaps a significant number of those who drive public buses and Grab vehicles are, as well.

In view of Singapore's rapidly ageing population, with more people continuing to work into their 70s, do our public transportation agencies provide comprehensive health-screening for new employees in the aforementioned positions?

If yes, what conditions - for example, diabetes, hypertension, cardiac and neurological conditions, visual problems and cancer - are included?

If job applicants have pre-existing medical conditions, how are they certified fit for driving, especially for shifts that may be up to 12 hours a day?

Also, how often do older drivers go for mandatory medical check-ups? Do these include a proper physical examination or only a perfunctory one?

In addition, are drivers clearly advised to stop their vehicles if they feel unwell, and to seek medical attention immediately? Or do they avoid doing so out of fear of not meeting quotas or key performance indicators, or punitive measures from the companies they work for?

There are about 41,000 and 100,000 holders of the Private-Hire Car Driver's Vocational Licence and Taxi Driver's Vocational Licence respectively.

The health of these drivers is of great concern not just to their passengers, but to pedestrians and other road users as well.

I hope the relevant agencies (including private-hire companies) will provide this information and ensure that adequate safeguards are in place.

Oh Jen Jen (Dr)