DOI: https://doi.org/10.62204/2336-498X-2025-1-17

SIMULATION OF VEHICLE MOVEMENT AT UNREGULATED

INTERSECTIONS OF PUBLIC ROADS

Anatoly Palchyk,

Candidate of Technical Sciences, Associate Professor,

 National Transport University, Kyiv, Ukraine,

pamproekt@gmail.com; ORCID: 0000-0003-2544-5359

Sergey Neizvestnyi,

State Enterprise National Institute for Infrastructure Development, Kyiv, Ukraine,

neizvestniyjony@ukr.net; ORCID: 0000-0002-8888-313X

Annotation. Developments in the field of computer software for modeling transport processes and their analysis represent modern software products that are becoming a powerful modeling tool. In the world practice, well-known simulation software products in the field of traffic flow organization are widely used, one of which is VISSIM (PTV AG, Germany). The PTV VISSIM simulation software can greatly simplify the work of the designer and creates a reliable platform for the design of road transport and urban planning facilities. To date, the first steps have already been taken in Ukrainian practice to address the issue of the feasibility and relevance of using transport modeling in Ukraine, especially in assessing the effectiveness of design solutions for road infrastructure. The purpose of the article was to present the results of traffic flow simulation to assess the availability and number of free traffic intervals between vehicles while driving at intersections of public roads using PTV VISSIM. The object of experimental research was an unregulated intersection of highways at the same level H-01 Kyiv-Znamianka (category II) and O100209 Uzyn – Vasyliv – Hermanivka – Trypillia (category IV). To achieve this goal, the following tasks were solved: a simulation model was developed at the experimental site (unregulated intersection); the availability and number of free traffic intervals for the existing traffic management option was assessed; measures to increase the number of free traffic intervals at the selected experimental research site were proposed and their effectiveness was evaluated.

Keywords: reconstruction, highway, traffic interchange, road infrastructure, traffic intensity, traffic flow, free traffic interval, maximum traffic intensity, traffic flow modeling.

Introduction. Unfortunately, Ukrainian practice today does not require the mandatory use of traffic modeling software, but only mentions the feasibility of their use. However, it should be noted that the first steps have already been taken to address the issue of the feasibility and relevance of using transport modeling in Ukraine, especially in assessing the effectiveness of road infrastructure design solutions. For example, with the participation of experts from the State Agency for the Restoration and Development of Infrastructure of Ukraine, the State Enterprise National Institute for Infrastructure Development, and Pro Mobility Limited Liability Company, the first edition of the Methodological Recommendations for Modeling Traffic Flows in Assessing the Effectiveness of Road Infrastructure Design Decisions was developed MR – B.2.2-37641918-928:2023 [8]. The above methodological recommendations contain a description of traffic flow modeling methods at different levels of detail (micro and macro), as well as algorithms for collecting and compiling the necessary information for modeling using PTV GROUP software systems, but there is no mention of the mandatory use of transport modeling tools.

In the world practice, well-known simulation software products in the field of traffic flow organization are widely used, one of which is VISSIM (PTV AG, Germany). PTV VISSIM is a tool for creating traffic flow models. Therefore, for the modeling experiment, we developed a simulation model of traffic flow on sections of the public road network that will allow us to determine both the parameters of vehicle movement and traffic efficiency indicators.

The scope of VISSIM:

1. Evaluation of the impact of the type of road intersection on the capacity (unregulated intersection, regulated intersection, roundabout, railway crossing, interchange at different levels).
2. Design, test and evaluate the impact of traffic signal operation on traffic flow.
3. Assessment of the transport efficiency of the proposed measures.
4. Analysis of traffic management on highways and city streets, control of traffic directions both on individual lanes and on the entire roadway.
5. Analysis of the possibility of giving priority to public transport and measures aimed at priority passage of trams.
6. Analysis of the impact of traffic management on the situation in the transport network (regulation of traffic inflow, change of the distance between forced stops, inspection of entrances, organization of one-way traffic and lanes for public transport).
7. Analysis of the capacity of larger transport networks (e.g., highway network or urban street and road network) with dynamic redistribution of traffic flows (this is necessary, for example, when planning intercepting parking lots).
8. Analysis of measures to regulate traffic in railway transport and in the organization of waiting areas (e.g., customs offices).
9. Detailed simulation of the movement of each traffic participant.
10. Modeling of public transport stops and subway stations, taking into account their mutual influence.
11. Calculation of analytical indicators (more than 50 different estimates and analytical coefficients), graphing (in Microsoft Excel) of the temporary network load, etc.

The PTV VISSIM simulation software can greatly simplify the work of the designer and creates a reliable platform for the design of road transport and urban planning facilities [2-7, 10].

Unlike simpler models based on constant speeds and unchanged following behavior of vehicles in front, PTV VISSIM uses the WIEDEMANN psychophysiological model of perception. The main idea of the model is to describe the process of movement of individual vehicles in as much detail as possible, to establish a functional relationship between individual flow indicators, such as speed and distance between vehicles in the flow. The use of such models allows you to estimate the dynamics of traffic speed, delays at the intersection, queue length and formation, etc. Therefore, different driver behavior is simulated using distribution functions for speed and distance [1].

Solving the problem of traffic flow distribution on the road network with increasing traffic intensity requires specification of the initial data on the characteristics of road conditions and traffic flows. The main volume of information is static information and relates to the description of the characteristics of the network, which is used to distribute traffic flows in the event of traffic obstacles.

Information on road conditions of a particular road network includes:

– road network layout;

– road category;

– geometric characteristics of the road network;

– road surface type and roadway condition;

– values of traffic delays;

– values of traffic intensity on the road;

– location of traffic obstacles on the road network and characteristics of each obstacle;

– location of entry and exit points for the distribution of traffic flows;

– scheme of traffic organization.

Objective and methods. The purpose of the simulation modeling is to assess the availability and number of free traffic intervals between vehicles while driving at intersections of public roads, as well as to analyze the effectiveness of the proposed measures to increase the number of free traffic intervals at the selected research object.

To achieve this goal, a simulation model of vehicle traffic on the selected section of an unregulated intersection of highways at the same level was developed. The intersection of the highways H-01 Kyiv-Znamianka (II category) and O100209 Uzyn – Vasyliv – Hermanivka – Trypillia (IV category) was chosen as the object of research on traffic flow parameters. For this object, we conducted field observations of vehicle traffic and obtained the actual values of time intervals between packages and between vehicles in packages during the corresponding maneuvers (left and right turns) and verified the accuracy of the proposed analytical models.

 Results and explanation. To develop a simulation model of vehicle traffic at the intersection of national (H-01) and regional roads (O100209) near the city of Obukhiv, Kyiv region, the PTV VISSIM software package was chosen.

The main input parameters in this case are [11]:

– length of highway sections;

– width of the roadway;

– number of lanes on road sections;

– intensity of traffic flow at the entrance to the intersection of roads;

– composition of the traffic flow;

– availability of public transportation stops, etc.

The sequence of building a simulation model of vehicles at an intersection of public roads using PTV VISSIM consists of the following list of main stages, which is given in Table 1 [11].

Before you start developing a simulation model, you need to upload the background (substrate) on which the simulation will be performed. Such a background can be an electronic map of the relevant area and scale, which is available on specialized resources such as Google Maps, SAS Planet or others. In this study, the background is a map fragment from the specialized resource Google Maps.

The first step is to model segments. Using the “Segments” object located in the “Network Objects” window, roads are drawn.

In the “Segment Attributes” window, as shown in Figure 1, you can see the length of the modeled section, name the segment, set the number of lanes for vehicles, and configure the type of road behavior displayed, the type of road surface, and the level of the multi-level interchange.

Next, add oncoming traffic. In the drop-down menu, as shown in Figure 2, select the “Oncoming traffic” item and activate it by pressing the corresponding key on the mouse.

After that, the connecting segments are modeled. To do this, if the Segments button is activated in the Network Objects window, as shown in Figure 3, you select the initial segment and draw a connecting segment from the first (selected) segment to the second. In the dialog box, you specify the parameters of the segment and set the right turn rule: for example, from the rightmost to the rightmost lane. You can also specify the number of intermediate points.

Next, you define the input flows according to the directions of movement. The “Input streams” item in the “Network objects” window is activated. Select the segment where you want to insert the input stream, most often it is highlighted in black, as shown in Figure 4. 

After that, the intensity and composition of the incoming traffic flow is set through the Quick View menu tab, as shown in Figure 5.

Next, for each connecting segment, we build low-speed traffic zones. To do this, activate the “Low-speed traffic zones” item. Select the connecting segments (right and left turns). The construction sequence is shown in Figure 6.

After that, priority rules are introduced for vehicles passing through the conflict zones. In the “Network Objects” window, select the “Conflict Zones” item and determine the priority of traffic in the conflict zone. As a result of the modeling, they are highlighted with yellow markers on the screen, and after determining the priority – with a red and green marker, respectively, as shown in Figure 7. To determine the right of priority passage and prevent congestion in the zone of unregulated exit from the adjacent territory, in the “Network Objects” window, select the “Priority Rules” item and set the priority rules for conflicting flows.

The next step is to set the routes of vehicles. In order to set a route solution, you need to activate the Vehicle Routes item in the Network Objects window. As you can see in Figure 8, the resulting route is highlighted in yellow.

If necessary, pedestrian traffic is modeled in the same way as vehicle flows are entered into the model. To organize public transport traffic, you need to enter stops and routes with the required stops and timetable. Public transport stops can be created both on the lane and in the pocket (public transport stops in a special lane extension of the selected segment).

After modeling the traffic flow at the intersection, you can start simulating the movement of vehicles on the selected object. A view of the traffic flow schedule is shown in Figure 9.

It should be noted that the result of the simulation model is the animation of traffic in the form of a real-time graphic and the subsequent output of transport and technical parameters, such as, for example, the distribution of travel time, traffic delays, queue length, idle time, the amount of emissions of harmful substances, fuel consumption, which can be differentiated by user groups.

After simulating vehicle traffic using PTV VISSIM, average delay values for different intensities per lane were obtained and the availability and number of free traffic intervals were analyzed for the actual and maximum traffic intensity. The estimation of the availability and number of free traffic intervals (Table 2) and average delay values are shown in Table 2.

As a result of an experimental study of traffic flow [9], the dependence of the number of free traffic intervals on the hourly traffic intensity was established (Formula 1):

where tᵢ and tᵢ+ⱼ are the interval of movement sufficient to perform right and left turn maneuvers without traffic complications, s;

N is the hourly intensity of one traffic lane, vehicle/hour.

With an increase in traffic intensity by 100 cars/hour or more, for the existing variant, there is a significant jump in the average delay (the ratio of the total delay time to the number of vehicles) at the facility. The main reason for this is that there is practically no possibility of making a left turn maneuver from all directions (very dense traffic).

To improve the traffic conditions, namely to reduce the average traffic delay, a simulation model of traffic at the intersection with transitional high-speed lanes for cars moving on the right along the main road was developed. A graphical representation of the traffic simulation is shown in Figure 10.

The results of the assessment of the reduction in average traffic delay after the installation of transitional high-speed lanes on the main road are presented in Table 3. They indicate the effectiveness of the installation of transitional high-speed lanes on the main road. Their installation can significantly reduce traffic delays, which continues the effective functioning of the interchange and the road.

Conclusions. The analysis of traffic simulations has shown that the main impact on delays is exerted by the flows of the main direction (main road). When the maximum traffic intensity is reached (i.e., when all free intervals are filled with vehicles), a significant increase in average traffic delay is observed. At actual traffic intensities of 500 to 800 vehicles per lane, there are free intervals (from 5 to 30 %), and at actual traffic intensities of 900 vehicles per lane and more, there are almost no free intervals (2 % or less). The results of calculating the availability of free intervals depending on the intensity are shown in Table 4.

This indicates a fairly high accuracy of the developed dependence of free intervals on traffic intensity and the possibility of using it to assess the period of effective operation of a road section and make a decision on the complete reconstruction of the road or the reconstruction of only the interchange.

The results confirm the effectiveness of improving traffic conditions by arranging transitional high-speed lanes on the main road, but it should be borne in mind that the redirected traffic flows will cause additional load on the secondary road, the consequences of which are to be determined in further research.

Possible further directions for research are consideration and modeling of other measures to improve traffic management at this interchange, for example, consideration of the possibility and feasibility of arranging a roundabout at one level as a transitional type of interchange before reconstructing it into different levels.

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