Vietnam's narrower car lanes initiative weighs safety trade-offs against smoother traffic

Major General Do Thanh Binh, director of the Ministry of Public Security’s Traffic Police Department, said Wednesday that his department will work with local authorities to assess possible lane-width reductions. Under Vietnam’s national technical standards, lane widths vary by road class: 3.5–3.75 meters on urban arterials and Class I city roads; 3.25–3.5 meters on main roads in Class II and III cities; and 2.75–3 meters on side streets.

Many urban roads currently have two 3.75-meter lanes, wide enough that three cars often squeeze side by side. "If lanes are reduced to 3.5 meters, two cars driving close together will push motorbikes to the right, which is safer than the current situation," Binh said.

He cited Nguyen Trai Street in Hanoi as a candidate for reorganization into six lanes to separate cars and motorbikes. He also pointed to Thanh Tri Bridge, where separating motorcycles from cars and lowering speeds has "clearly" reduced accidents.

"Traffic flow will improve, fuel consumption and emissions will fall, and people’s frustration with congestion will be reduced," he said of potential benefits.

Traffic jam on Nguyen Trai Street in Hanoi, January 2025. Photo by VnExpress/Ngoc Thanh

Backing the idea, Dr. Phan Le Binh, chief representative of Oriental Consultants Global in Vietnam, said narrower lanes can save urban space, reduce land clearance for new roads, and lower construction costs. He noted that in Japan many urban lanes are 3–3.25 meters wide and "operate normally," typically with dashed white lines to permit lane changes.

He suggested that on slow-speed urban corridors, a two-lane, 7-meter carriageway could be narrowed to 3–3.25 meters per lane to create room for motorbikes and non-motorized traffic. "Drivers may feel uneasy at first, but they will adapt. In practice, cars in inner cities already travel very close to each other," he said.

Other experts warned of safety risks. Dang Van Chung, vice president of the Vietnam Automobile Transport Association, said the widest cars approach 2.5 meters; allowing roughly 50 centimeters of lateral clearance on each side justifies today’s 3.5-meter urban lanes, while expressways and major arteries use up to 3.75 meters for higher speeds.

"If lanes are narrowed to 3.5 meters or less, side-swiping between oncoming vehicles or between vehicles traveling close together at speed becomes more likely. Trucks and buses will have difficulty maneuvering and may collide with adjacent vehicles when turning," he said, recommending the change only on routes with very high vehicle density.

Dr. Dinh Thi Thanh Binh of the University of Transport added that at 45–50 kph, at least 50 centimeters of lateral clearance per side is needed to avoid collisions from lateral movement, a particular challenge for large trucks.

She noted that current lane widths are anchored in standards tied to speed and road class; any narrowing would require revising those standards.

She also cautioned that on heavily trafficked urban corridors with frequent intersections, strict lane separation may be ineffective because vehicles must change lanes often. Even if space is reallocated to motorbikes, cars may encroach.

Experts urged authorities to study feasibility and run pilots on selected streets, paired with supportive traffic management. Recommendations include avoiding continuous white lines (which prohibit lane changes) on narrowed lanes and holding off on penalizing minor lane incursions during the trial period to give drivers time to adjust.