As the level of motorization rises, transport streams in city street networks become more extensive. Such a situation is especially evident in large and very large cities. Under those conditions the development of the existing street network is not as fast as the rate of intensification of transport stream traffic.
To assure fast and safe traffic in present-day cities, complex architectural, planning and organizational measures should be taken. In this case, organizational measures enable to solve a part of the transport problem only. More drastic would be measures providing for reconstruction of the street network, promotion of its density.
The street network displays the parameters in the following range: planning structure, length, density, as well as other parameters. At the same time, the important practical task is to identify reasonable street network parameters, in particular, street network density.
Identification of essential parameters of the route network of municipal passenger transport is another important aspect of effective operation of the municipal passenger transport system.
1 Transport Zoning
This term paper project is focused on the analysis of the transport system in a city having a specified number of residents. Figure 1.1 below presents the city layout chart with the indication of housing types. The topological layout is a model of the municipal transport network and must give the most precise description of the modeled site. Besides, the topological layout must describe every zone of the of the street network, as well as all transport areas in the city. The topological layout depicts a part of the street network where management of city route traffic of surface-type transport can be possible. The topological layout scale is 1:50000.
The transport calculations providing for consideration of the whole city transport system involve subdivision of the city territory into separate transport areas, including specification of their centers.
When solving the tasks of municipal passenger traffic, the transport area bounds and centers should be designated so that all movement within a transport area can be made on foot, while all movement between transport areas can be reduced to movement between their centers. To fulfill this requirement, there exist two approaches applicable to designation of transport area centers:
1. The transport area centers are assigned at stop stations that demonstrate the highest rate of passenger exchange.
2. The transport area centers should be assigned so that average distances of passenger travels between transport areas can be equal to distances between their centers.
Figure 1.1 Topological layout with indication of housing type:
– industrial zone; – 3-5-storied housing; – 9-12-storied housing; – 1-2-storied housing; – 5-9-storied housing;
– 12-16-storied housing
In the course of city micro-district zoning the following rules should be observed:
1. The maximum transport area may not exceed 2.5 km2, the maximum distance and time for a passenger to reach a stop should be 800 meters or 10 minutes.
2. Rivers, railway tracks, woods, and other natural obstacles, as well as bounds of city administrative districts should serve as natural boundaries of transport areas and should not be inside them.
3. The transport areas should not divide buildings, parks, plant or factory territories.
4. Large passenger-absorbing sites (such as enterprises, stations for all types of transport, large transfer stations for municipal passenger transport, metro stations), including all adjacent territories should be singled out into separate transport areas.
5. Transport area boundaries may not pass along large arterial highways servicing routes of municipal passenger transport and must cross them at the right angle.
6. Any two adjacent transport areas must be connected via one main traffic artery; an exception can be made in respect of two parallel streets of oncoming one-way traffic.
7. Transport area boundaries must not be close to a stop station having a high rate of passenger exchange.
8. All dead-end zones of the transport network, including adjacent territories should be singled out into separate transport areas.
9. Not more than one intersection of transport lines should be within one transport area.
10. Should the traffic of municipal passenger transport be run along two streets of a different traffic capacity, in certain cases it would be advisable that the street of a lower traffic capacity be enveloped by the transport area and not be considered as a separate main traffic artery.
11. As concerns transport areas, having a junction of intersection of transport lines, the intersection point should be taken as the center.
12. If and when possible, the transport area centers should be equidistant from the transport area boundaries, not only in respect of distances, but also in respect of approach time, convenience, etc.
13. Taken as the transport area center should be one of the entrance stops for municipal passenger transport, which is normally the stop having the highest rate of passenger exchange; if a metro station is available, it should be taken as the transport area center.
At the next stage of the analysis, the city territory will be broken down into transport areas, with the consideration of the above requirements (Figure 1.2). To establish transport areas, it should be assumed that the routes of municipal passenger transport may function in all zones of the street network.
At the next stage it becomes necessary to assess the total city area, each transport area and areas occupied by housing of appropriate types within each particular transport area.
Figure 1.2. Topological city layout with indication of transport area boundaries
Figure 1.3. Topological city layout broken down into 25 mm2 squares
2 Street Network Parameters
The street network is described as the length of segments connecting adjacent transport areas. The segment lengths will be measured by a ruler on the city map. The measurement values will be converted into the actual lengths with the use of scale values.
Figure 2.1 Pattern of city street network
3 Calculation of Population Size in Transport Areas
At the first stage the size of population in each transport area should be calculated.
Then there will be calculated the value of population relative density, size of population in transport areas, the value of population density in respect of each area.
Calculations of the number of residents or people who are provided with employment here can further be carried out in any scale; the only requirement would be to maintain precision of calculations down to one person. The population size and density should be calculated in respect of each transport area.
4 Assessment of Departure and Arrival Capacity of Transport Areas
Considering the way to state the problem, the arrival capacity of a transport area is the number of people who arrive in the area as first-shift workers. Distribution of work places in the city territory depends on availability of industrial zones where 30 % of city residents work in the first shift and work places in the other territory of the city, which provide employment for 10 % of population. Therefore, the total number of employed city residents during the period under review makes 40 % of population. The number of people who work in industrial zones is proportional to their areas, while the number of people employed in residential zones is proportional to the areas of such zones and population density therein.
Proceeding from the above, prior to solve the task of separation, one should first assess the total number of first-shift workers, the number of people who work in industrial and residential zones, and, afterwards, density of industrial zone manpower.
There will be determined in respect of each area the number of workers in the industrial zones, density of workers in residential zones, number of workers in residential zones, general number of workers in transport areas, number of people leaving each of the transport areas, departure and arrival capacity of transport areas.
5 Identification of Street Network Parameters
The source data are based on transport network characteristics and departure and arrival capacity of transport areas. The computer-calculated source data are generated to follow the instructions as to application of the program for evaluation of effectiveness of transport network operation (ro net.ехе).
To calculate the transport network source characteristics, the following tasks should be solved:
– calculation of shortest-distance matrix;
– calculation of correspondence matrix;
– prior estimation of effectiveness of transport network operation.
To solve the above tasks, the data presented in the following format should be entered in the first ro net.ехе program file, which was made: start station; end station; arc length (in hundred meters); speed of arc free traffic (km/hour); traffic lane number multiplied by 10 (the program is intended for 3.5 m-wide lane; therefore, the actual lane width value is divided by 3.5 and multiplied by 10).
The next file describes restrictions pertaining to the network; the format of entry in this file is as follows: station, from which no traffic can start; station through which no traffic may pass; station to which no traffic may be directed.
The third file presents the data on departure and arrival of transport facilities from/to transport junctions in the following format: transport junction number; departure capacity; arrival capacity.
The computer-aided calculation of the shortest-distance matrix is based on the criterion of the minimum time of traffic of transport facilities from one station to another one.
To identify the optimum route of traffic between street network junctions, the program searches all travel options and defines the option enabling to attain the criterion that was chosen.
The next stage involves computer-aided program calculation of correspondences between transport network junctions. The software adopts a gravitational model for estimation of transport network correspondences.
The source data used to calculate the correspondence matrix represent volumes of generation and absorption of transport streams in network junctions, network characteristics and shortest-distance calculation results.
The results of calculation of shortest-distance and correspondence matrices serve as the source data for prior estimation of the effectiveness of transport network operation. The computer-aided program executes distribution of transport streams and defines traffic intensity with all network arcs being used. Traffic intensity is predicted with the reference of the morning rush hours.
Effectiveness of transport network performance is based on one of the chosen criteria with the consideration of estimated network arc traffic intensity. In this case the total time of traffic of transport facilities within the network will be used as the effectiveness criterion.
The analysis of network operation parameters involves calculation of the string of parameters for the purpose of identification of low-effectiveness zones, the so called “bottlenecks” in transport network performance; there must be calculated the parameters that characterize transport streams and permit to make conclusions as to presence or absence of “bottlenecks”. Belonging to such parameters are the road traffic loading coefficient and speed variation coefficient. The road traffic loading coefficient will be calculated in respect of each zone of the transport network.
6 Calculation of Route Network Parameters for Municipal Passenger Transport
There will be calculated the quantity of transport facilities for the carriage management purposes, total passenger turnover, average network travel distance, volume of carriage by route passenger transport during the period under review, network-average traffic interval, combined length of municipal passenger transport routes, average time of pedestrian travel to stop station, average time of transport facility expectation at stop station, average time of route travel, passenger transfer average time.
Grounding on the calculation results, the investigation work conclusions will be made.