The Ministry of Transport is drafting a Circular to promulgate National Technical Regulations on Expressways. One of the notable points of the draft is that in the case of expressways applying a design speed level higher than one level (20km/h), there must be a transitional section of at least 2km in length with an intermediate design speed level.
The draft also stipulates that the design speed of expressways is divided into 3 levels as follows:
Level 120 has a design speed of 120km/h.
Level 100 has a design speed of 100km/h.
Level 80 has a design speed of 80km/h; for locations with particularly difficult terrain and controlled by national defense and security factors, a design speed of 60km/h is allowed.
On expressways, there may be sections applying different grades, but these sections must be at least 15km long and the design speed of two consecutive sections must not differ by more than 20km/h. In cases where expressways apply a design speed grade that is one grade higher (20km/h), there must be a transition section of at least 2km in length with an intermediate design speed grade.
The draft sets out some general requirements for highways as follows:
The structure of highway works must ensure stability, durability, and suitability to natural conditions.
Expressways have a minimum scale of 4 lanes (2 lanes for each direction), with emergency lanes arranged continuously (except for the following locations: across bridges with a span of 150.00 m or more; bridges with pillars 50.00 m or more high; tunnels; with acceleration and deceleration lanes; and auxiliary lanes for climbing slopes).
Works associated with expressways include: Service roads or side roads; Traffic management and operation centers; Rest stops, stops, and parking lots; Non-stop electronic toll collection systems for toll roads; Vehicle weight control works; Protective fences.
The cross-section of a highway can be arranged on the same roadbed or the two directions of traffic can be arranged on two separate roadbeds.
The standards for highway cross-sections are as follows:
The number of lanes is determined based on the design traffic volume, but not less than 2 lanes in each direction. The minimum lane width is 3.75m for grade 120 and 100 roads and a minimum of 3.50m for grade 80 roads.
The emergency lane has a minimum width of 3.00m for grade 120 and 100 roads and a minimum width of 2.50m for grade 80 roads.
Mid-range standard
Arrange a median strip (including a median strip and a safety strip on both sides of the median strip) to separate two directions of traffic in the case where the highway cross-section is arranged on the same roadbed. The minimum width of the safety strip is 0.75 m for grade 120 and 100 roads and a minimum of 0.50 m for grade 80 roads. The median strip is designed to ensure safety.
In case the two-way traffic is arranged on two separate roadbeds without a median strip, on the left side of the traffic direction, a safety strip and a dirt shoulder are arranged. The safety strip has a minimum width of 1.00m for grade 120 and 100 roads and a minimum width of 0.75m for grade 80 roads.
Minimum curb width is 0.75m, surface is planted with grass or other materials to prevent erosion.
