In expressway with 8 lanes and above (including the first-class highway), when the first and second lanes inside are mainly used for small vehicles, the lane width can be 3.5 meters. For expressway (such as airport expressway, etc.). ) which is mainly used for medium and small passenger cars, lane width of 3.5 meters can be demonstrated. The "new standard" no longer stipulates the recommended value of the central median width, but is adjusted to "determined according to the function of the central median of highway projects".

In addition, the width of the hard shoulder on the right side of expressway and the first-class highway that undertakes the trunk line function is generally 3m, and the minimum value is1.5m. When the bus is the main vehicle, the right hard shoulder can also be 2.5 meters.

The subgrade width of highways at all levels shall be designed according to Technical Standard for Highway Engineering (JTG B0 1-2003).

Extended data:

In order to meet the standards for heavy vehicles on main roads and improve the compactness and resilience modulus of subgrade, 4% quicklime soil is replaced within 0.3m of the main roadbed of a section of filled road, and 15cm unscreened gravel is replaced in the main roadbed of a section of general filled road.

For general filled subgrade, the slope ratio is 1: 1.5. When the local ground cross slope is greater than 1: 5, the fill subgrade shall be dug into steps with a width of not less than 2m, and an inward cross slope of 4% shall be set. Due to the need of clearance under Sunjiazui Bridge in expressway, Han and Hubei, the design elevation of subgrade in this section is low, so it is necessary to set up protective dikes to improve the flood control standard.

At the same time, cantilever retaining wall is set to adjust the height difference between motor vehicle lane and non-motor vehicle lane. The elevation of protective hoisting is 18.5 1m, and the slope ratio outside hoisting is 1:2. The slope ratio of the inner side changes with the design elevation of the non-motor vehicle lane. TK6+480~TK9+ 1 12 section, because the rainwater drainage in this section adopts the combination of pipeline and open ditch drainage.

Therefore, when the filling height of this part is greater than 2.. 1m, the secondary slope is adopted, and the slope ratio of the primary slope is 1: 1.5 (or 1: 1.75, which is suitable for the reservoir section; Or 1:2.0, which is applicable to the channel modification section).

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