The chief executive of the Hong Kong Automobile Association (AA) on Monday welcomed the government’s new e-toll system, but said authorities should do more promotion as many drivers still have not signed up for e-toll tags.

The new system came into operation on Sunday and authorities confirmed about 16 percent of those who passed through the tunnels on the first day did not have the e-tag.

Officials also said that while the new service’s operation was smooth, some drivers still slowed down at toll booths before tunnel workers quickly waved them through.

On RTHK's Hong Kong Today programme on Monday, the association’s Owen Chan warned that if cars stop suddenly before entering the tunnel, then this could lead to an accident.

Chan also suggested that tunnel operators could install loudspeakers reminding drivers not to slow down and to just pass through, adding they could also update noticeboards.

"You need more noticeboards to remind the drivers, also need time to know the arrangement. Also, the tunnel companies need to check the position of the direction boards and make sure that drivers can read it."

He said some of the reasons cited by drivers as to why they have not signed up for e-tags include not thinking it is necessary, or they prefer the old system.

But overall, he said association members liked the system, which improved traffic flow as drivers need not stop at toll booths to pay.

But Chan said that one complaint from drivers was that they would receive three messages on their phones regarding the e-toll – one confirming they are using the service, one saying that they are using the e-tag, and another confirming that they have paid the toll fee.

"I think three messages are annoying when you're driving, and you received several messages. If you check the message it may affect your driving. So Hong Kong AA hopes they make it simple, one message is more than enough."