What is the width of an 8-lane road?

[August]

Standard lane width: 3.75 meters; Emergency stopping lane: 2.5 meters; Central divider: 1 meter; For an 8-lane road including emergency stopping lanes: 3.75X8+2.5X2+1=36 meters; Including other ancillary facilities (guardrails, etc.), it can be calculated as 40 meters. U-turn rules at traffic lights: 1. No U-turn allowed when there is no left-turn lane before the traffic light; 2. No U-turn allowed on the crosswalk at the traffic light, must pass the crosswalk before making a U-turn; 3. If there are clear signs prohibiting U-turns or left turns at the traffic light intersection, no U-turn is allowed at any time; 4. No U-turn allowed when the road centerline at the traffic light intersection is a double solid yellow line. If it's a double yellow line with one solid and one dashed, vehicles on the dashed side can make a U-turn, while vehicles on the solid side cannot; 5. If there are yellow grid lines at the traffic light intersection, U-turns are allowed, but vehicles must not stop on the yellow grid lines; 6. If there is a U-turn sign or a dedicated U-turn signal light, follow the green light instruction to make a U-turn; 7. If there is no U-turn light but there is a left-turn light, wait for the green light in the left-turn lane before making a U-turn.

[MacLucy]

Last time I went on a long-distance trip, I paid special attention to this. According to national standards, a bidirectional eight-lane highway should have a one-way width of over 15 meters for its four lanes combined. The leftmost overtaking lane is typically about 3.75 meters wide, while the other travel lanes are roughly 3.5 to 3.75 meters wide. However, when actually driving, you'll notice that factors like the median strip and emergency lanes must be included, making the total width of the entire road easily exceed 30 meters. For instance, during the reconstruction of certain sections of the Beijing-Shanghai Expressway, the central green belt and shoulders on both sides were factored in to meet this standard. If you see an eight-lane road in urban main roads, the emergency lane might be narrower, but the total width won’t differ much as long as the number of lanes remains the same.

[SanMaximus]

What I fear most when driving myself is encountering poorly planned lanes. The standard eight-lane design should have a width of 3.75 meters × 4 per side, but when passing through tunnels or bridge sections, it often narrows to 3.5 meters, making it particularly oppressive when large trucks drive side by side. I remember once driving on a cross-sea bridge on a rainy day—the total width of the bidirectional eight-lane bridge was 37 meters, but due to the inward shift of guardrails, the actual lanes felt narrower than those on a regular highway. It's even more noticeable on urban expressways, where after accounting for green belts, some intersections see the eight-lane width shrink to a total of 28 meters.

[LeAlexandra]

Tested the newly opened eight-lane expressway near my home. According to design standards, each lane is 3.75 meters wide, making it 15 meters for one direction. Adding a 2-meter central green belt and 3-meter shoulders on each side, the total road width is 37 meters. However, during rainy days when lane markings are hard to see, it's easy to straddle lanes, making me wish the lanes were wider. Still, compared to six-lane roads, changing lanes during traffic jams is much easier on an eight-lane road.

[HectorAnn]

Comparing domestic and international standards: In China, each lane of an eight-lane highway is typically 3.5 to 3.75 meters wide, with a total width ranging between 34 to 38 meters. U.S. interstate highways are narrower, where a minimum of 3.65 meters can qualify as a lane, and eight-lane roads as narrow as 32 meters in total width have been observed. Europe places greater emphasis on safety margins, with some German autobahns featuring lanes as wide as 3.8 meters. However, in practical driving conditions, the clarity of lane markings proves more critical than the mere difference of a few centimeters in width.

[LeFernando]

Only after participating in road reconstruction projects do you realize that width isn't so rigid. The standard cross-section for an eight-lane bidirectional highway in flat areas is 2×15.5m driving lanes + 3m central median + 3m shoulders on each side. But in mountainous areas, adjustments are made flexibly: lanes widen to 3.85m on curves, compress to 3.5m in tunnels, and emergency lanes also narrow. The most extreme case I've seen was a 36m-wide urban elevated eight-lane road that squeezed in four 3.6m lanes + narrow shoulders.