What are the categories of roads
The main determining factors forhighway construction is the intensity of vehicle traffic, speed mode and axle load. Depending on this, the width and pavement are projected. The categories of roads are set according to the aggregate of the following indicators: actual and reduced traffic intensity, number of lanes, speed of movement, width of strip, width of dividing strip, width of reinforcing edge strip, width of roadbed, maximum longitudinal slope, radius of curve in turn. The main categories of roads in the Russian Federation are I, II, III, IV, V.
I and II categories of highwaysAre assigned to sites with a capital type of coverage, which include different roads, having from one to several lanes in each direction. They are designed for speeds of up to 120 km / h (1a - up to 150 km / h), they can drive cars with axle load up to 10 tons, they have wide strips (3.75 m), maximum gradients are limited to 3-4%, radii turns up to 1200 m.
Wide roadsides and dividing strips (onlyfor the I category of roads) provide security and the necessary throughput. The maintenance of highways of this category includes a wide range of works, in particular, for the I and II categories of roads, snow is cleaned, icing is cleaned, as movement is carried out all year round.
For roads of the III category, where the smallerthe intensity of movement, the facilitated improved cover is equipped. They are allowed to width of strips up to 3.5 m and turning radii - 600 m, their maximum slope can reach 5%. But at the same time, vehicles with axle loads of up to 10 tons can drive through sections of Category III. The rated speed mode for them is not more than 100 km / h, the number of lanes to each side is not more than two.
The IV category includes roads with a solidcoating, but it may not have improvements (coating of gravel, cobblestones). The width of the lanes on them is no more than 3 m, the maximum of longitudinal slopes can reach 6%, the minimum turning radius is 250 m. The maximum axial load is 6 tons, in winter they should be cleaned, but on the cover one can leave a layer of ice and snow.
If roads do not have improved coverage,spring period on them can be imposed a restriction on the movement of machines of a certain carrying capacity. The reason for this lies in the fact that in the spring, because of the high humidification of the roadway, its supporting capacity decreases, and under the influence of a certain axial load deformation of the pavement can occur. If the restriction is not introduced, then in spring such roads should be moved cautiously, taking into account the fact that due to the arising nerves and cracks the rolling friction can constantly change, which complicates the control of the machine.
V category includes roads that do not havehard surface (laid on a common ground). To increase the stability of the upper layer, their surface is sometimes treated with special binding additives. In the period of mudslides or during heavy snowfalls, it is permissible for them to stop moving. As a rule, they have only one lane, their design speed does not exceed 60 km / h.