Scheme of the organization of the road network and traffic flow for the outpost equestrian base territory planning project. Schemes for constructing city road networks

In Soviet and foreign urban planning, a wide variety of schemes for constructing a street and road network are used. However, an analysis of the layout of various cities allows us to speak about the existence of fundamental geometric schemes that determine the configuration and outline of their main majority. Each of these schemes has its positive and negative sides.

The most common of them would be the following:

The rapid growth of automobile traffic in cities revealed a discrepancy between planning and technical specifications outdated network of city streets with modern transport requirements.

Thus, practice has shown that in old cities private entrances and exits from microdistricts to main streets form a dense network of intersections, which significantly reduces the intensity, speed and safety of traffic.

In this regard, when planning new cities, it is recommended to apply the principle of sequential adjoining of one category of streets to another (the “tree” or “river” principle). Its essence lies in the fact that each transport junction must be formed either by equal categories of streets, or by streets that differ by only one category in the sequence: entrance -> driveway -> residential street -> main street of district significance -> main street of city significance –> city road (Fig. 4.3.).

In any case, the compositional design of the road network should not be based on formal considerations. It must be determined by the specific conditions of the area, meeting the requirements of the architectural and planning idea of ​​​​building a city.

In general, when assessing the design of urban highways, one can be guided by such a general indicator as density street network, which is determined by the ratio of the total length of streets (km) to the area of ​​the city (km 2).

The need to classify the network of city streets and roads arose in connection with the need to ensure the movement of all types of urban ground transport within the city. The purpose of the classification is to divide traffic into homogeneous traffic flows in accordance with the functional purpose of the streets.

To increase the capacity of city streets and ensure clear organization of traffic, it is necessary to unify the rolling stock and make it more homogeneous. This makes it possible to distribute transportation along individual highways of the city and according to the degree of impact of the rolling stock on environment(noise, vibration, air pollution), carry out these transportations taking into account the functional zoning of the city.

Currently, there is only a functional classification of city streets, dividing all city streets according to their purpose, but not according to technical indicators. This is explained by the fact that the street network is included in the master plan of the city with an orientation towards a very distant future (50 - 100 years) and for the development of this network the territory is reserved along the boundaries of which urban development is located. The boundary separating the street from the building area, beyond which buildings should not extend, is called red lines. All elements of the street that provide pedestrian traffic and Vehicle, must be located within the red lines.

Placing sidewalks, roadways and other street elements within the allocated areas that ensure the passage of future traffic intensity is more important than standardizing the technical parameters of these streets (Table 1.3).

The accepted classification establishes the minimum number of elements of the transverse profile of the street and their main dimensions. An increase in these sizes is possible with a feasibility study, the basis of which is calculations to assess the street capacity, traffic safety and transport losses. Such calculations are mandatory when designing city streets and virtually eliminate the uncertainty associated with the lack of technical classification. The same street category may, depending on the expected intensity

Continuation of the table. 1.3

traffic have different widths of the main roadway, local driveways, medians and sidewalks. But in any case, the minimum technical equipment of a street is determined by its functional purpose.

The main transportation of passengers and goods in cities is carried out on main streets. It is these streets that determine the type of road network of the city. The number of main streets and their length are determined by the expected level of motorization of the city. For domestic cities, this level is accepted as 180 - 220 cars. per 1000 inhabitants. Smaller numbers refer to the largest and largest cities, larger ones to medium-sized cities and towns. For this level of motorization, the density of the main road network, defined as the ratio of the length of main streets to the area of ​​the district, should be 2.2 - 2.4 km/km 2 of the city territory. This density does not have to be uniform throughout the city. In the central part of the city there is a dense

The number of main streets should be increased to 3.0 3.5 km/km 2 , in peripheral areas with residential buildings - to 2.0 2.5 km/km 2 , in industrial areas - reduced to 1.5 - 2.0 km /km 2, and, in forested areas - up to 0.5 - 1.0 km/km 2.

The density of the local street network in inter-highway areas can reach 2 km/km 2 . It should be taken into account that the placement and storage of personal cars are assumed to be on the roadway of the local street network. The standards for the design of residential areas provide for the placement on the territory of microdistricts of at least 70 % cars of citizens living in this microdistrict, taking into account the estimated level of motorization. Car storage areas in neighborhoods must accommodate at least 25% of passenger cars.

Streets and roads form a network of surface communication routes on the city plan. Based on its outline, it can be attributed, with more or less significant assumptions, to one of the fundamental diagrams of the city’s road network. Such patterns are free, not containing a clear geometric pattern, rectangular, rectangular-diagonal and radial-ring.

Free schemes streets are typical for old southern cities. The entire network consists of narrow, curved streets with a variable width of the roadway, often excluding the movement of cars in two directions (Fig. 1.9, A). Reconstruction of such a street network, as a rule, is associated with the destruction of existing buildings. For modern cities, this scheme is unsuitable and can only be left in protected parts of the city.

Rectangular diagram is very widespread and is characteristic mainly of young cities or old (relatively) ones, but built according to unified plan. Such cities include Leningrad (central part), Krasnodar, Alma-Ata. The advantages of a rectangular scheme are the absence of a clearly defined central core and the possibility of uniform distribution of traffic flows throughout the city (Fig. 1.9, b). The disadvantages of this scheme are a large number of heavily loaded intersections, which complicate the organization of traffic and increase transport losses, and large overruns of cars in directions that do not coincide with the directions of the streets.

The adaptability of the street network to the requirements of modern urban traffic is assessed by the coefficient of non-straightness - the ratio of the actual length of the path between two points to the length of the overhead line. For a rectangular street pattern, this coefficient has the greatest value - 1.4-1.5. This means that in cities with such a street layout, urban transport for the transportation of passengers and goods makes overruns by 40 - 50% With the same traffic volumes, traffic intensity on streets of such cities with all the ensuing consequences (fuel consumption, environmental pollution, increased av

speed, congestion of streets with traffic) is 25 - 40% higher than in cities with radial-ring schemes.

Rectangular-diagonal pattern streets is a development of the rectangular scheme (Fig. 1.9, V). It includes diagonal and chord streets, made through existing buildings in the most congested directions. The non-straightness coefficient for such schemes is 1.2-1.3.

This scheme somewhat improves the transport characteristics of the city's street network, but creates new problems: crossing the city diagonally causes the appearance of complex intersections with five and six merging streets. At low traffic intensity (in total on all streets less than 1,500 vehicles per hour), a roundabout scheme can be used to interchange them; at high traffic levels, traffic interchanges on two and three levels can be used.

Radial-ring scheme street network is typical for the largest and largest cities and contains two fundamentally different types of highways - radial and ring (Fig. 1.9, G).

Radial highways are most often a continuation of highways and serve to deeply introduce traffic flows into the city, to connect the city center with the periphery and individual areas with each other. Ring highways are, first of all, distribution highways that connect radial ones and ensure the transfer of traffic flows from one radial highway to another. They also serve for transport links between individual areas located in the same zone of the city.

An example of such a layout is Moscow. The layout of its street network has evolved historically. The core of this network was the Kremlin. As the city developed as a capital Russian state it was surrounded by city buildings and defensive structures - earthen ramparts and fortress walls. These structures determined the emergence of ring highways. Currently, the number of radial highways has been increased to 20, and ring highways to 3. In the master plan for the development of Moscow, it is planned to increase the number of ring highways to 4, and to improve transport connections between the outer regions of the city, where residential and forested areas of the city are now being created, 4 will be built chord highways belonging to the category of expressways.

The radial-ring scheme of the city's road network does not require the presence of completely closed rings. It is important to ensure the movement of traffic flows from one radial highway to another in the shortest direction - tangential. Individual chords can be located in this direction. It is desirable that they overlap each other and provide communication between all radial highways. The closer to the city center, the greater the need for completely closed rings. On the periphery of the city, the need for transverse transport links is dictated mainly by the volume and direction of freight traffic.

The radial-ring scheme of the street network has the lowest coefficient of non-straightness - 1.05 - 1.1.

Rice. 1.9. Schemes of the city street network:

A- free; b- rectangular; V- rectangular-diagonal; G- radial-ring

In their pure form, all the considered street network schemes are rare in modern large cities. As the city and its transport system develop, the street layout increasingly takes the form of first a radial scheme, and then, after the construction of bypass roads along the city boundaries and streets encircling the city center, a radial-circular one. Within one district, a rectangular street pattern is most often maintained.

Control questions.

What indicator is used to determine the size of a city?

What functional zones are distinguished on the territory of modern cities? What are the boundaries of these zones?

What schemes exist for connecting the city with external roads?

4. How does the layout of the city’s road network affect the load and capacity of the streets?

5. On what basis is the modern classification of the city’s road network based? In determining which street parameters is the estimated traffic speed used?

The status quo

The territory of the designed sports and leisure center is located in Istra Municipal area Moscow region between the villages of Leonovo and Kartsevo. Transport communication between the territory of the planned location of the sports and leisure center and the villages and towns of the Istrinsky district is carried out along the Volokolamskoye Highway – Buzharovo – Savelyevo – Rumyantsevo highway.

Car roads

The Volokolamskoe Highway - Buzharovo - Savelyevo - Rumyantsevo highway is a highway regional significance III technical category. In the area under consideration, the width of the carriageway is 6 m. Road markings are applied to the carriageway. The markings mark two lanes for vehicle traffic in both directions. Artificial lighting There is no highway on the section of the road under consideration.

Project proposals

Project proposals for transport services for the territory of a sports and leisure center are developed with the aim of streamlining and ensuring the safe movement of vehicles and pedestrians, for the purpose of their transport services and determining the location of car parking.

Roads and streets

External transport connections of the territory under consideration will be carried out along the regional highway “Volokolamskoye Highway – Buzharovo – Savelyevo – Rumyantsevo”.

The project provides for two planned streets of local importance for the passage of motor vehicles into the territory of the sports and leisure center. Entry and exit to the territory of the sports and leisure center is carried out from the planned local street located to the north of the territory in question. Access to the Volokolamskoe Highway – Buzharovo – Savelyevo – Rumyantsevo highway is carried out along the planned local street located to the west of the territory of the sports and leisure center.

The project provides for the reconstruction of the Volokolamskoye Highway - Buzharovo - Savelyevo - Rumyantsevo highway, maintaining two lanes and increasing the roadway to 7.00 m. It also provides for the construction of 2.50 m shoulders on each side of the road (0.50 m reinforced lane curbs on each side of the road). The width of the roadway is taken to be 8.00 m (4.00 m is the width of the traffic lane in each direction, taking into account the passage of horse-drawn vehicles). The planned transverse profiles of streets and highways are presented on the sheet “Scheme of organization of the road network and traffic flow” (profiles 1-1, 2-2, 3-3).

Expressway lanes have been installed along the highway in the area where local streets adjoin it. Exit from the planned street to the highway is carried out in both directions of the road. The parameters of the transitional express lanes and the radii of the junction curves of the highway and the planned street are adopted in accordance with SNiP 2.05.02-85 “Highway Roads” and can subsequently be clarified in accordance with the technical specifications of the State Administration of the Moscow Region “UAD MO “Mosavtodor”.

It is planned to apply appropriate road markings along the highway and streets and install appropriate road signs in compliance with GOST R 52289-2004 “Technical means of organization traffic. Rules for the use of road signs, markings, traffic lights, road barriers and guide devices", GOST R 51256-99 "Road markings. General technical conditions" and GOST R 52290-2004 "Road signs. General technical conditions".

Network of internal passages

The exit of vehicles from the territory of the sports and recreation complex is carried out in the checkpoint area to the street located north of the territory in question. Departure is carried out in both directions of the street. The driveway provides access to the administrative building and a parking lot for 13 cars. To the east of the junction of the driveway with the street, there is an entrance and exit to an open-air parking lot designed for 68 cars. The minimum width of driveways is 8.00 m. The radius of curvature of the roadways of driveways at junctions with the street is 8.00 m.

The driveways are equipped with asphalt concrete pavement, closed rainwater drainage and installation of curb stones. At night, it is proposed to illuminate the entire designed internal network of passages using lamps installed on special masts.

Traffic at junctions between driveways and streets is regulated road signs and road markings.

Structures and devices for temporary storage of vehicles

The maximum one-time estimated number of visitors to the sports and recreation complex is 300 people. The number of permanent employees is 12 people, temporary – 30 people. Thus, in accordance with TSN 30-303-2000 “Planning and development of urban and rural settlements. Moscow region" the maximum estimated fleet of cars will be 95 units. For visitors it is necessary to provide 90 parking spaces at the rate of 30 parking spaces per 100 people. For employees, 5 parking spaces at the rate of 15 parking spaces per 100 employees.

In the area of ​​the administrative building there is an open parking lot for 13 cars. The open-air parking lot, located east of the main entrance, has a capacity of 66 cars and has a separate entrance from the street. Also along the local street there are parking spaces adjacent to the roadway for 16 cars.

Thus, the total capacity of open parking lots in the territory under consideration is 95 parking spaces.

Public transport

On the Volokolamskoye Highway – Buzharovo – Savelyevo – Rumyantsevo highway, it is planned to locate a public transport stop south of the sports and leisure center territory within 400 m of accessibility.

Pedestrian traffic

Pedestrian movement is planned to be organized along sidewalks along the highway, streets and driveways. Places where pedestrian and traffic flows intersect are equipped with pedestrian crossings (with appropriate road markings and appropriate road signs).

Along the Volokolamskoye Highway – Buzharovo – Savelyevo – Rumyantsevo highway there is a 1.50 m wide sidewalk on the side of the sports and leisure center. The sidewalk also connects the area in question with a public transport stop. Along the planned local street, located to the west of the sports and leisure center, sidewalks 1.50 m wide are provided on both sides of the roadway. Along the planned local street running from the north of the territory under consideration, a sidewalk 3.00 m wide is provided on the north side of the roadway. On the eastern side of the sports and leisure center there is a 3.00 m wide sidewalk connecting the sidewalks of the highway and the planned local street.

Traffic through the territory of the sports and leisure center is planned to be organized along sidewalks and pedestrian paths 1.5-3 m wide; pedestrian movement is also allowed along the roadway.

Having studied this chapter, the student must:

know

• provisions and theoretical basis formation of the city road network;
• regulatory legal and regulatory technical documents in the field of designing urban road networks;
• rules for designing urban road networks;

be able to

• summarize and systematize the main documents regulating the design and functioning of the city road network;
• solve problems related to determining the parameters of streets and city roads;
• choose the most rational design solutions for pedestrian traffic and parking infrastructure;

own

• skills to work with regulatory and scientific literature in the field of design and operation of urban road networks;
• skills in solving practical problems in calculating the parameters of streets and city roads.

Planning structure of the street and road network. Its main characteristics

Street and road network(UDS) is a complex of objects transport infrastructure, which are part of the territory of settlements and urban districts, limited by red lines and intended for the movement of vehicles and pedestrians, streamlining development and laying utilities (with an appropriate feasibility study), as well as ensuring transport and pedestrian connections of the territories of settlements and urban districts as a component parts of their communication routes; is an interconnected system of city streets and highways, each of which performs its own function of ensuring the movement of its participants and the function of accessing the starting and ending points of movement (objects of gravity).

Street and road network of cities and settlements consists of city roads, streets, avenues, squares, alleys, embankment passages, transport engineering structures(tunnels, overpasses, underground and overhead pedestrian crossings), tram tracks, dead-end streets, driveways and entrances, parking lots and lots.

Planning for the development of the road network of cities and towns, as well as the placement of city streets and roads, should be carried out on the basis of urban planning standards, land use and development rules, urban planning regulations, types of permitted use of land plots and capital construction projects, urban planning plans for land plots and based on from element placement planning structure(blocks, microdistricts, other elements).

The road network of populated areas should be formed in the form of a continuous hierarchically constructed system of streets, city roads and its other elements, taking into account the functional purpose of streets and roads, the intensity of transport, cycling, pedestrian and other types of traffic, the architectural and planning organization of the territory and the nature of the development.

A number of requirements are imposed on the planning structure of the road network.

• 1. Rational placement of various functional urban areas and ensuring the shortest connections between individual functional areas of the city. Within big city the time spent by residents traveling from their place of residence (residential areas) to their place of work (industrial and administrative areas) should not exceed 45–60 minutes.
• 2. Ensuring the necessary capacity of highways and transport hubs with division of traffic by speed and mode of transport.
• 3. The possibility of redistributing traffic flows in case of temporary difficulties in certain directions and sections.
• 4. Providing convenient access to external transport facilities (airports, bus stations) and access to country roads.
• 5. Ensuring safe movement of vehicles and pedestrians.

The planning structure of cities is formed taking into account natural conditions: terrain, presence of watercourses and climate. So, for example, in northern cities a network of streets will be created located in the direction of the prevailing winds in the winter season, ensuring the transfer of most of the snow through the city. In cities located on a slope, a network of streets is created, directed from top to bottom - the city is ventilated: the smog is transferred down to the valley.

There are the following planning structures of the city road network(Fig. 4.1).

• 1. Free scheme typical for old cities with a disorderly road network (Fig. 4.1, A). It is characterized by narrow, curved streets with frequent intersections, which are a serious obstacle to the organization of urban transport.
• 2. Radial scheme found in small old towns that developed as trading centers. Provides the shortest connections between peripheral areas and the center (Fig. 4.1, b). It is also typical for the road network developing around the city center. The main disadvantages of this scheme are the congestion of the center with transit traffic and the difficulty of communication between peripheral areas.
• 3. Radial-ring scheme presents an improved radial scheme with the addition of ring highways, which relieve part of the load from the central part and provide communication between peripheral areas, bypassing the central transport hub (Fig. 4.1, V). Typical for large historical cities. In the process of city development, non-urban roads that converged at the central hub turn into radial highways, and ring highways arise along the routes of dismantled fortress walls and ramparts, which previously concentrically encircled separate parts of the city. Classic example- Moscow.
• 4. Triangular pattern has not become widespread, since sharp corners formed at the intersection points of elements of the road network create significant difficulties and inconveniences during the development and construction of sites (Fig. 4.1, d). In addition, the triangular layout does not provide convenient transport connections even in the most active directions. Elements of the triangular scheme can be found in the old districts of London, Paris, Bern and other cities.
• 5. Rectangular diagram has become very widespread. Typical for young cities (Odessa, Rostov), ​​which developed according to pre-developed plans (Fig. 4.1, d). It has the following advantages over other planning structures:
  • – convenience and ease of orientation during movement;
  • – significant throughput thanks to the presence of backup highways that disperse traffic flows;
  • – no overload of the central transport hub.

The disadvantage is the significant remoteness of oppositely located peripheral areas. In these cases, instead of moving along the hypotenuse, the traffic flow is directed along two legs.

6. Rectangular-diagonal pattern is a development of the rectangular scheme. Provides the shortest connections in the most popular directions. While preserving the advantages of a purely rectangular diagram, it frees it from its main drawback (Fig. 4.1, e). Diagonal highways simplify connections between peripheral areas and with the center.

The disadvantage is the presence of transport hubs with many incoming streets (mutually perpendicular highways and diagonal).

7. Combined scheme preserves the advantages of some schemes and eliminates the disadvantages of others. Typical for large and largest historical cities. It is a combination of the above types of schemes and, in essence, is the most common. Here, in the central zones, free, radial or radial-ring structures are often found, and in new areas the road network develops according to a rectangular or rectangular-diagonal pattern.

Rice. 4.1.

A - free scheme; b– radial; V– radial-ring; G - triangular; d– rectangular; e – rectangular-diagonal

Depending on the planning structure, the load on the city center varies. Largest quantity transport connections through the city center have a radial network, since transportation is actively carried out along radial streets in the diametrical direction. The radial-ring scheme largely eliminates this drawback, since peripheral residents go along ring streets to bypass the center. The rectangular layout, which allows traffic flows to be dispersed along parallel streets, is also free from this drawback.

UDS is characterized by the following indicators.

1. Density of the street and road network is defined as the ratio of the length of roads to the area of ​​the territory, km/km2

Sometimes an indicator of specific network density is used, expressed in km2 of roadway area divided by km2 of city territory (km2/km2).

According to modern standards, the average density of main streets 5 = 2.2-2.4 km/km2 with a distance between them of 0.5-1.0 km.

The rational distance between the main streets along which public transport operates is determined based on the convenience of city residents, so that the distance from the most distant point of residence or work to a stop does not exceed 400–500 m.

With the same distance between streets, the network density with a radial-ring planning structure is 1.5 times higher than with a rectangular layout. High network density ensures a minimum length of pedestrian approaches to main streets, but has such serious disadvantages as high capital investments in network design and operation, as well as low traffic speeds due to frequent intersections at the same level.

The average density of the street network in St. Petersburg is 4.0-5.5 km/km2, including the density of the network of main streets and roads with controlled traffic - 2.5-3.5 km/km2, the density of the network of urban express roads and highways continuous movement – ​​0.4 km/km2.

The traffic density in Moscow is 4.4 km/km2. In large cities of the world, the traffic density is greater: in London – 9.3, in New York – 12.4, in Paris – 15.0 km/km2.

There is a relationship between the number of people in a city and the density of the street network. In small cities (with a population of 100–250 thousand inhabitants), the traffic density 6 = 1.6–2.2 km/km2, in cities with a population of more than 2 million inhabitants δ = 2.4–3.2 km/km2.

The larger the city, the greater the density of road networks and the greater the length of streets per resident. In large Russian cities, per resident there is the following amount of street area, m2: in Moscow - 12, in St. Petersburg - 10, in US cities: New York - 32, Los Angeles - 105.

2. Non-straightness index characterized by the value of the non-straightness coefficient equal to the ratio of the actual path that the car travels along the road network from the starting point A to end point route B, to the air distance between these points:

The non-straightness coefficient largely depends on the planning structure of the road network and the adopted traffic organization (primarily the volume of one-way traffic).

The coefficient of non-straightness varies from 1.1 to 1.4. The smallest nonlinearity coefficient has radial ring circuit, the largest is rectangular.

3. Capacity of the road network determined maximum number cars passing through the cross section per unit of time - hour.

The capacity of the road network depends on the load level of individual highways, the method of regulating traffic at intersections, the proportion of continuous traffic highways, the composition of the traffic flow, the condition of the surface and other reasons.

The throughput capacity at the same traffic density of rectangular and rectangular-diagonal schemes is higher than others - due to the presence of parallel backup streets.

4. Difficulty of highway crossings characterized by the configuration of the intersections of main streets.

The most rational, as experience shows, is the intersection of two main streets at right angles. The presence of five or more converging directions in a node significantly complicates the organization of traffic, forcing the use of ring schemes that require significant areas, or expensive interchanges at different levels. Intersections of main streets at sharp angles also complicate the organization of traffic and pedestrian traffic.

5. Load level of the central transport hub depends on the planning structure of the city center load.

The radial network has the largest number of transport connections through the city center, since transportation is actively carried out along radial streets in the diametrical direction. The radial-ring scheme largely eliminates this disadvantage, since peripheral flows are carried out along ring streets, bypassing the center.

The rectangular layout does not have this drawback, allowing traffic flows to be dispersed along parallel streets.

• SP 42.13330.2011 "Urban planning. Planning and development of urban and rural settlements." Updated version of SNiP 2.07.01–89*.

The basis of the city's road network - the main street and road network - consists of main streets, squares and roads of citywide and regional significance, along which the movement of public and all other types of transport takes place, connecting residential and industrial areas of the city with each other and with citywide and zonal centers, with citywide administrative, public, cultural, shopping and sports facilities, as well as recreation areas, parks and external road transport facilities (river ports, airports)

The road network develops gradually as the city grows. In old cities, as a rule, the road network was created over several centuries and its basis was the directions of country roads that at one time connected the settlement with the outside world.

The design of the main road network is inextricably linked with the design of the city master plan, both when creating new cities or new districts, and when reconstructing old cities. It is obvious that the most rational solutions can be obtained when designing new cities.

When developing master plans for the reconstruction of old cities, it is often necessary to change the directions of existing street directions, lay new streets, create streets along duplicate directions, and at the same time carry out reconstruction, and often demolition of adjacent buildings.

In the process of designing new areas of large cities, it is necessary to combine techniques for developing vacant areas with reconstruction methods. In all cases, when designing the main road network and master plan, it is necessary to be guided by a set of requirements, the basis of which is minimizing passenger and cargo transportation. This is achieved by correct functional zoning of urban areas, providing convenience and the least amount of time spent on all types of transport connections and, first of all, on movement from residential areas to places of employment, to cultural and public service enterprises, to the central core of the city and to the centers of planning zones and within urban transit traffic through the city center.

In this case, it is necessary to provide:

Placement of the main city-forming points, taking into account the minimum load of the street network with freight traffic by creating freight roads outside the central and residential areas of the city and such construction of the road network that will provide the necessary throughput of highways and transport hubs and the division of flows according to high-speed movements and by mode of transport;

Tracing the main highways along the shortest distances between cargo-generating and passenger-generating points.

In addition, the planning solution for the road network should provide high level safety of transport and pedestrians, greening of streets and maximum reduction of the negative impact of transport on the environment, expedient construction of a system of urban route transport, the possibility of redistributing traffic flows in the event of temporary difficulties in certain directions or sections thereof, as well as laying engineering underground and above-ground networks and structures .

The planning scheme of the road network can have any shape, but it is very important that its construction is clear and simple, not allowing mutual overlap of traffic flows due to the merging of various highways in individual sections, so that it contributes to the distribution of traffic flows and meets all the set of requirements placed on it.

The following types of road network planning schemes are distinguished: radial, radial-ring, rectangular, rectangular-diagonal, triangular, combined and free.

Radial scheme - most often found in old cities, which were formed at the intersection of external roads and developed in the direction of connections with other cities by country roads. With this scheme, communication between city districts and centers is well ensured, but overload of the central part of the city is inevitable and communication between districts is difficult. This scheme does not meet the requirements for a modern city transport system.

Radial-ring - the scheme is a radial scheme with the addition of ring highways, the number of which depends on the size of the city, and the location is determined by transport correspondence and local conditions. Ring highways remove significant traffic load from the central part of the city and create convenient connections between districts, bypassing the central city core. An example of a radial-ring system is the Moscow road network. In large and largest cities There may be several radial-ring areas around the centers of the city's planning zones. This scheme is called multifocal.

Rectangular layout - is a system of mutually parallel and perpendicular streets. It is usually found in relatively young cities, the construction of which was carried out according to pre-developed plans. The advantages of such a scheme include its simplicity, high throughput, the possibility of dispersing transport along parallel streets, and the absence of a single transport hub. The disadvantage of the rectangular scheme is the significant lengthening of the paths connecting diagonally opposite blocks and districts of the city.

Rectangular-diagonal pattern - is a rectangular pattern with the addition of diagonal connections. Here the advantages of the rectangular scheme are preserved and its disadvantages are mitigated. Thanks to diagonal highways, connections between peripheral areas and the center are simplified. The disadvantage of the scheme is the presence of nodes with many incoming streets, including at an angle, which makes it very difficult to organize traffic flow on them and place buildings.

A triangular pattern is rare due to the formation of a large number of nodes with the intersection of many highways under an acute node. In some old areas of London and Paris, such a construction of the road network is found.

Combined scheme - represents various combinations of dangerous above geometric schemes. It occurs quite often in large cities, where the old areas of the city have a radial-ring layout, and the new ones have a rectangular pattern.

Free scheme - the road network does not contain elements of the schemes described above. It is found in spontaneously developing Asian and medieval European cities. This scheme is applicable in difficult terrain conditions in resort cities or recreation areas.

For the technical and economic assessment of the road network, the following indicators are used: density, degree of non-linearity of communication, network capacity, average distance of city districts from each other, residential areas from the main places of employment from the city center or other important centers of gravity of all types of transport and pedestrians, the degree of loading by transit flows of the central transport hub, the configuration of the intersection of main streets.

The density of the road network is the ratio of the total length of streets in km to the corresponding area of ​​the city and its region in km2.

IN general view the density of the road network l km(km)2 will be equal to:

where, ?L is the sum of the lengths of streets and roads, km. When determining the density of the main road network? L represents the length of only main streets of both citywide and regional significance;

F is the area of ​​the city served by the sum of the lengths of streets and roads, km2.

With a high density of the main network of streets and roads of a city or its region, short pedestrian approaches are achieved, or, as is commonly called, approaches within walking distance to public transport stops. However, this leads to frequent crossings of main streets, which reduces the speed of communication.

The Building Codes and Regulations adopted in our country (Part 2. Design Standards, Chapter 60 “Planning and Development of Cities, Towns and Rural Settlements”, referred to for brevity and subsequent presentation as SN and P 11-60-75*), the average density of the main road network is normalized to 2.2 - 2.4 km/km2.

In the central districts of the city, the density of the road network can be increased to 3.5-4 km/km2, and in peripheral areas reduced to 1.5-2 km/km2, but not less than the density at which the walking distance to the nearest stop public transport does not exceed 500 m (including the length of the pedestrian path through the territory of the microdistrict) and is reduced to 300 m in climatic subregions IA, IB, IIA, and to 400 m in climatic region IV.

The degree of non-straightness of the road network is determined by the ratio of the sum of the distances between the main points of the city along the street network to the sum of the distances between the same points along straight air lines. To characterize this indicator, the coefficient of non-linearity is used.

where, ?Lф - the sum of the actual distances between the main points of the city, measured along the entire network of main streets; ?Lв - the sum of distances between the same points, measured along straight air lines.

A more comprehensive description of the degree of non-linearity of the city’s road network is obtained taking into account the average distances.

The average practical distance is determined by the formula:

L f. Wed =?L f /n

Where, n is the number of correspondences (i.e., the number of pairs of points between which the average distance is measured); =?Lф - the sum of the actual distances between these points, measured along the road network.

The average distance between these pacts, measured along overhead lines, will be equal to:

Lv.sr = ?Lv/n

Taking into account the average distance, the non-straightness coefficient is determined from the expression:

l = L f. Wed / L w.wed

To evaluate the road network based on the coefficient of non-straightness, you should use the following data proposed by A. E. Stramentov:

Table

It is recommended to design road networks with a degree of non-straightness from very low to high. At very high and exceptional high values It is necessary to reduce non-linearity by compacting the road network, straightening certain important directions, and introducing diagonal directions.

The radial-ring scheme of the road network has the lowest coefficient of non-straightness of 1.00-1.10; with a rectangular-diagonal scheme it can fluctuate between 1.11 - 1.20, and with a rectangular scheme - from 1.25 to 1 ,thirty

The average distance of residential areas from places of employment, from the city center or from any other mutually corresponding points is determined not simply as an arithmetic average, but as a weighted environment, taking into account the population size in certain zones of the city.

To determine the average distance between two points of the city (for example, from residential areas to an industrial zone or residential areas to the city center), concentric circles are drawn on the city plan at a distance of one kilometer from each other, the average distance is determined, and the number of population in each kilometer zone is determined .

The average distance is Lup km, and there will be

Lup = H n1 L n1 + H n2 L n2 +…..+ H nn L nn /H

where H n1 H n ….. H nn population of each kilometer zone

L n1 L n2 …..L nn - average distance of each kilometer zone from the considered industrial zone of the city center

N - city population

The average communication time more accurately characterizes the city's road network than the average distance, especially for large cities.

The average communication time between different points of the city is determined in the same way as the weighted average, taking into account the nature of settlement, and is found from the expression:

T up = H n1 T n1 + H n2 T n2 +…..+ H nn T nn /H

where - T n1 T n2 …..T nn average communication time to each zone min

In general, the city's road network should be designed in such a way that the total time spent on one-way travel from the place of residence to the place of work for 80-90% of the population does not exceed 40 minutes in large and major cities. This standard is also preserved for other cities where the place of labor is located at a considerable distance from residential areas, as, for example, in the case of industry that is hazardous to sanitary requirements and is located with a large protection gap zone. In other cities and populated areas, the communication time between residential areas and places of employment should not exceed 30 minutes.

The design of the city's planning structure, its transport systems and road network can be divided into three stages. At the first stage, the main tasks are solved - the functional zoning of the urban area, the placement of the most important objects, the direction of the main connections and the orientation and density of the backbone network; at the second stage - placement of objects of secondary importance and branching of the network. The main task when designing a road network is to develop an option in which, taking into account the totality of various requirements, a high level of transport services for the population will be provided with minimal total capital investments in transport construction.