A plastic shield around the bus driver's seat could serve a dual purpose in the future as the pandemic brings about renewed safety concerns, with drivers now threatened by both the coronavirus and unruly commuters.

With an increase in the number of cases of assault of bus drivers this year, the National Transport Workers' Union (NTWU) is revisiting an idea floated two years ago.

Then, stakeholders, including bus operators, the NTWU and the Land Transport Authority (LTA), had trialled the use of plastic shields as protection for bus drivers against assault, although this was eventually scrapped as drivers said the screens reflected light and affected driving.

This year, with bus drivers coming into conflict with one or two commuters who refuse to wear a mask every day, the problem has come to a head.

Said NTWU executive secretary Melvin Yong: "In the light of the recent cases of bus captains being verbally abused or physically assaulted by commuters, NTWU is revisiting the idea of installing plastic shields to better protect bus captains - both in terms of virus and assault prevention.

"NTWU will work with LTA and the PTOs (public transport operators) to study the various options available, and once there is a good prototype, we will look at scaling and implementing it in the buses."

On Sept 15, an SBS Transit bus driver was berated and then beaten up for 12 minutes by a passenger who boarded the bus without wearing a mask.

The passenger, Ja'afally Abdul Rahim, 52, has been charged with voluntarily causing hurt to the 39-year-old driver. Ja'afally has also been charged over carrying a knife with a 6cm blade and 6cm handle on the bus.

On SBS Transit's buses alone, nearly 40 similar cases of assault have been reported this year, with about half of them mask-related.

This is up from 33 cases in the whole of last year. SBS told The Straits Times that those incidents were usually fare-related. Some commuters were also drunk when altercations occurred.

In July, SBS Transit began trialling transparent protective shields around the driver's seat on six of its buses, but this was aimed solely at minimising contact and transmission of Covid-19 between the driver and commuters.

SMRT has also made an application to LTA to install plastic screens on its buses, although it is unclear if this was prompted by the coronavirus or cases of bus driver abuse.

NTWU said that its most recent efforts take into account the 2018 trial failure. This time, it will improve or use a different material for the screens so as to reduce the glare from the plastic shields.

It will also make sure that bus drivers can get in and out of their seat easily to allow them to help those with physical disabilities board the buses.

Mr Yong said: "While there are options available in the market, we will need to explore the feasibility of installing these in our existing buses.

"We want to remind commuters of their responsibility to wear a mask in public areas so as to safeguard their personal health, as well as the health of other commuters and front-line workers," he added.