Determination of Regularities in the Development of Intermodal Hubs’ Planning Structure in «Smart» Cities

This article is an attempt to determine regularities in the development of transport and transfer hubs. One of the components of the “smart city” concept is the “smart transport”. The development of the transport system of a locality is one of the cornerstones for sustainable development of the urban territory, creating comfortable environment for human activities. The transport and transfer hub is the reference point of interaction between the urban environment and the transport infrastructure. When elaborating urban planning documentation for transfer hubs, special focus shall be made on the creation of comfortable and safe environment using the Transit Oriented Development (TOD) principles. At present, in Russia, the baseline document for territorial planning, which determines the limit parameters of the planned territory development, is the planning design. In Moscow and Moscow region, audacious transfer hub development programs have been adopted. Still, the regulatory and procedural framework for transfer hub planning is currently at the stage of elaboration. The goal of this study is to ascertain regularities between relevant and anticipated features of transfer hubs, based on approved hub plans in Moscow region. In particular, to reveal the dependence between the sizes of commercial areas making part of a hub, and the passenger traffic volume. The study uses the statistical method of regression analysis, which allows determining the function between dependent and independent variables. The model obtained can subsequently be used to calculate the limit parameters of the hub territory development, both at the stage of creating the hub development concept, and at the planning stage, to make well-grounded decisions as to limit parameters of the development.


Introduction
The organization of state-of-the-art transport systems as part of the "smart city" concept implies the extension of intermodal public trips. The term "intermodal" is understood as a trip using several kinds of public transport, or personal and public transport. The development of intermodal transfers is impossible without development of the transport system's nodal pointstransport and transit hubs (TTH) 1, 2, 3, 4 et al..
To ensure maximum comfort, convenience and safety of passengers travelling through transfer hubs, standard development requirements, i.e. the statutory framework for urban planning of transfer hubs, shall be put in place. The elaboration of regulations and guidelines requires a wide range of research to be conducted, in particular, the detection and study of regularities between the hubs' objective and planned parameters.
The key objective of this paper is the exploration of dependences between a TTH's objective parameters and projected performance. The study is based on approved hub planning designs in Moscow region.
Till 2030, in Moscow region, 120 TTH projects will be implemented. The list of transfer hubs is approved by Decree of Moscow Region Government dated March 20, 2014 № 168/9 «On transfer hub development in Moscow region» [5] (fig. 1). Till 2021, in Moscow, about 147 TTHs will be created [6]. Intermodal transfer hub programs are implemented by the Russian Railways JSC, and by a number of Russia's biggest cities (Saint Petersburg, Kazan, etc.).  [7], and in some individual references made in regional urban planning standards [8, 9, 10 et al.]. Currently, the Institute for General Planning of Moscow has prepared the "Transport and transfer hubs" guideline, to be approved in 2019 [11,12]. Moreover, certain procedures shall be elaborated, governing the transfer hub formation, based in particular on the study and systematization of existing solutions approved by administrative documents. We have examined and analyzed a number of approved hub layout designs in Moscow region prepared in the last few years, in order to determine the regularities in the anticipated development of transport and transfer hubs.

Methods
Public data of approved TTH territory planning designs in Moscow region will be used as the source material for the study. Currently, 28 transfer hub planning designs have been approved ( fig. 1).
The objective of the study is to reveal presence (or absence) of dependences between TTHs' objective parameters and projected performance characteristics. One of the possible approaches is the statistical method considering the influence of any one or several independent variables upon a dependent variablethe regression analysis [13, 14, 15 et al.]. The regression analysis allows determining the dependent variable's values using the independent variable.
In our study, the general population are transfer hubs in Moscow region with approved layout designs.
To conduct a regression analysis, we will draw a summary table (table 1) with quantitative values, which will be checked for the existence of any dependence. The following dependent variables shall be included in the table:  TTH's parameters defined in administrative acts, subject to the functional purpose of areas and territories;  Passenger traffic, calculated pursuant to the predicted use of various modes of transport, and subject to the additional load from the TTH's commercial component.

And independent variables:
 Territory occupied by the TTH;  Distance from the TTH to Moscow Ring Road (MRR);  Travel time by personal transport from the hub to the MRR  Area of the TTH's influence zone. The objective of this paper is the study of dependences between projected and objective TTH parameters, therefore, we use the planned territory area to estimate the distribution within the general population, as it is the most objective indicator of a TTH's role and importance. Calculations were made which showed that, within the general population, the TTH distribution follows the normal law, which allows the study to be conducted.

Results
All possible kinds of indicators' dependences on each other were examined: 28 cases in all. It is ascertained that in 10 cases, there is a function between the indicators. Further, the graphic functions where checked for stochastic dependences by regression analysis. The calculations made have shown that the existing dependences are polynomial. Polynomial functions have the following form: = + 1 + 2 2 + ⋯ + (1) where: хindependent variable; ydependent variable; afree term of the estimation line. This is the value of y, when x=0; bangle factor. This factor shows y's increase with increasing x.
As the paper considered dependences between two variables, the following condition shall be met: the number of examined factors of every one independent variable shall be above 10, but below 100.
Upon completion of the regression analysis, the final table was drawn, containing the values of all coefficients.
When performing the regression analysis, we should first of all focus on the R square (determination) coefficient. The higher is the coefficient, the most accurate and precise is the model. If the R square coefficient is under 0.5, the regression analysis is deemed unreasonable.
The first value of Y-crossing shows what will be the Y value, if all X variables in the model are equal to zero.
The variable coefficient X1 shows the weight of Y variable's influence upon the X variable. The sign preceding the coefficient shows the type of dependence (direct or inverse).
Pursuant to the results of the regression analysis, R-square is above 0.5 in the following dependences of functional and layout elements:  Dependence of the projected commercial zone area on the TTH territory area is exponential, regression equation    In these dependences, the multiple R coefficient is above 0.72, which evidences a strong interconnection between the dependent and the independent variables.
The calculation data are shown as diagrams in Fig. 2 to 5. Pursuant to the performance diagrams, it can be seen that the predicted projected dependent variable Y takes values below 0, which is impossible, as Y means the area of a territory. Therefore, minimum parameters of the independent variable should be introduced. The considered dependences take the form of quadratic equations, thus, the minimum value of the area will be a positive equation root.
Minimum area values:  Dependence of the commercial zone area on the TTH territory area -x min = 1.9 ha. This means that if a TTH territory is less than 1.9 ha, the deployment of commercial areas is unreasonable.  Dependence of the aggregate area of TTH facilities on the TTH territory area -= 1.5 ha. If a TTH territory is less than 1.5 ha, the deployment of TTH