The additional lanes are part of efforts by the city to increase the rate of passengers using public transport to 20-25 percent, authorities said last week. Public transport only meets 15.7 percent of demand now.

But experts voiced concern about the plan for increasing the number of lanes, saying the city is not ready for it.

Bui Danh Lien, former vice chairman of the Hanoi Transport Association, said the transport infrastructure is inadequate, pointing to narrow roads and numerous crossroads.

"Setting up priority lanes for buses will lead to greater congestion. Hanoi should delay implementation of this plan to improve infrastructure conditions."

Besides, when the city does prioritize lanes for buses, it should make sure other vehicles do not encroach on them like they do now in the Kim Ma - Yen Nghia bus rapid transit (BRT) route.

Hanoi's only BRT route was launched in 2017 and runs 14.7 kilometers (9.1 miles) between two of the city's most populated areas.

Statistics from the Department of Transport show that in the first six months of this year over 700 vehicles drove every hour on To Huu Street, part of the Kim Ma – Yen Nghia BRT route.

Dr Nguyen Xuan Thuy, who has researched urban transport for more than 30 years, said 2020 is not the right time for Hanoi to increase the priority lanes.

The new lanes are planned on the Phap Van – Giai Phong – Dai Co Viet (4.7 km), Nguyen Van Cu – Ngo Gia Tu (5.9 km) and Pham Hung – Khuat Duy Tien – Linh Dam (9.6 km) routes.

The Nguyen Trai - Tran Phu and Pham Hung - Khuat Duy Tien routes are crowded while bus services are inadequate, Thuy said. "So most people use private vehicles, meaning priority lanes on these narrow roads are not practicable."

Hanoi’s target to raise the ratio of passengers using public transportation is difficult to achieve because the public is not interested as buses travel slowly, he said.

"I think it will take at least 5-10 more years for priority lanes for buses to become viable."

Hanoi should consider carefully to ensure the work is not done and then abandoned as unviable, he said.

Dr Phan Le Binh, a lecturer at the Vietnam Japan University, is among the backers of the plan: "The priority lanes for buses will cause traffic congestion in the immediate future, but it is a necessary congestion for people to give up the habit of using personal vehicles and switch to public transport."

The priority lanes should have been created 10 years ago because if the city waits for all infrastructure to be in place before doing so, it could never happen, he said.

Hanoi first experimented with a priority lane for buses on the five-kilometer Nguyen Trai – Tran Phu route in 2008. Binh said it was not done properly and was unsuccessful.

It was eventually abandoned to facilitate the construction of Hanoi's first metro line.

Besides the BRT route, Hanoi currently has only one 1.3 km long route prioritized for public buses, starting from Long Bien bus station in Ba Dinh District to the intersection of Thanh Nien - Nghi Tam - Yen Phu in Tay Ho District.

The city has nearly 2,000 buses, which operate at an estimated average speed of around 23.8 kilometers per hour but most inner city buses average 16 kph.

Serving 1.2 million passengers daily, they meet 12 percent of transport demand.

City officials have said that they are trying to make public transport as convenient as possible to resolve the traffic jams that often clog roads by reducing the use of private vehicles.

There are six million cars and motorbikes registered in the city, another two million have been brought from other provinces and the police and defense forces have another million, according to city Party chief Hoang Trung Hai.

To put these numbers in perspective, the capital’s population is 7.7 million.

The Department of Transport proposes to pilot a motorbike ban on two roads that run parallel in Thanh Xuan District in the west of the downtown area.

But experts and the public are unhappy with the idea, pointing out that public transport is yet to meet the needs of the public and cars too are a major cause of traffic jams.