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The purpose of traffic flow modeling is to predict how vehicular traffic will be redistributed in the considered area after a new bridge is built, a new street (road) or street (road) section is built, existing roads or the network of streets (roads) are widened or reconstructed. traffic will be prohibited in the section, traffic regulation with signs will change, etc

Traffic flow simulation is also used in 3D mode to represent the traffic situation after the implementation of the future reconstruction of the road network. In this way, reconstruction solutions are tested, possible design errors are avoided, and funds are saved, which would be allocated to correcting possible errors already after the implementation of the project. Traffic flow modeling can be used to model the consequences of emergency situations (when for some reason traffic is blocked in a part of the road or street network) and to search for optimal solutions for such a situation.

There are several programs for modeling traffic flows. We use AIMSUN 8 EXPERT.
The main tasks solved by the program:

• assessment of the impact of infrastructure projects on traffic;
• evaluation and optimization of redistribution of traffic intensity;
• evaluation and optimization of traffic control (with signs, traffic lights, marking of the road surface);
• traffic safety analysis;
• analysis and optimization of intelligent transport systems (ITS);
• environmental impact assessment of traffic;
• evaluation and optimization of the benefits of road charging.

A video demonstrating the operation of the program:

Video player


A fragment of the resulting results (example):

Current distribution of traffic flows in
street network fragment X, auto./h.







Distribution of traffic flows after the closure of the western crossing in

Sidra Intersection 6 software is used to model intersections when preparing investment projects for intersection reconstructions.

This software makes it possible to theoretically evaluate the change in the parameters of the existing position of the reconstructed intersection in comparison with alternatives for the reconstruction of the intersection.

Using this software and having forecasts of future traffic flows, the predicted situation in the future (e.g. 25 years from now) is evaluated under different reconstruction alternatives. The program has the ability to simulate intersections controlled by traffic lights, roundabouts and signs. Intersections can be of various geometrical structures: with pedestrian islands, separating lanes, roads intersecting at non-perpendicular angles. The program can calculate the length of queues of cars at the intersection, the time spent, pollution, fuel consumption, and the optimal time of traffic light phases. During the simulation, the traffic of pedestrians, passenger cars and goods vehicles is evaluated separately. The program presents part of the calculated intersection indicators in textual form, and the other part in both textual and graphical form.

A fragment of the resulting results (example):




The existing situation at the reconstructed intersection is modelled.
Visualization of the provided services while driving in different directions.








The predicted situation after the reconstruction of the intersection.
Visualization of the provided services while driving in different directions.

An important stage in the implementation of infrastructure projects is planning. This is preparatory work, during which the need for the planned project, economic, social and environmental benefits, expected results are determined, possible project implementation alternatives, costs, etc. are compared.

Following the international terminology, the initial phase of project justification is often called ” pre-feasibility study “. A detailed justification is called a feasibility study . However, sometimes both of these studies are classified as initial justification, while detailed justification is simply called “justification” or an investment project .

Feasibility studies and investment projects assess how one or another project is useful to society, calculate the likely benefits and costs of the project. For economically viable projects, funds spent on construction and project maintenance must pay for themselves within a specified project evaluation period. These studies, together with the project funding applications, are submitted to the EU structural funds and national institutions that finance the projects and are used in making decisions on whether or not to allocate the requested funds.

The content of a typical feasibility study or investment project includes:

• Project summary. It is designed so that it can be used separately from the feasibility study and evaluated as a separate document. The summary provides an overview of work administration, preparation and management information, indicates the project goals, briefly describes the project, needs analysis, alternatives, technologies, cost, presents evaluation results and conclusions;
• Information about the implementation of the project: name of the project, place of execution, organizers, beneficiaries, what categories the project is, according to which program it would be implemented, its compatibility with public policy and law is described, institutional and political aspects are presented;
• Project justification. This section presents the justification of the project in terms of essential socio-economic aspects and the analysis of the existing transport infrastructure;
• Project goals: the critical points of the current situation are identified, the need for the project is presented with goals and reasons. Technical indicators of the project are presented, their description (with alternatives and planned works);
• Environmental aspects. General data on economic activities, project developers and environmental impact assessment document developers are provided. The environmental situation at the site of the project preparation and the impact of the planned activities on the environment are named. An environmental impact assessment is carried out and a description of preventive measures is prepared;
• Project implementation plan: a project preparation, implementation and management schedule and project implementation schedule are drawn up;
• Social impact: it describes the impact the implemented project will have on the users of the facility, its influence on the population living in the zone and performing various economic activities;
• Financial analysis: financial indicators are calculated;
• Economic analysis: the economic indicators of the project are calculated;
• Sensitivity and risk analysis.

Risk evaluation

Palisade @Risk 6.2 Industrial software is used for risk assessment of infrastructure projects. The risk assessment method used by this software is Monte Carlo simulation. The simulation is performed after evaluating the factors influencing the project risk, their possible values, and the possible distribution of values. The program has the ability to describe various types of variable value distributions (normal, triangular, binomial, Poisson and others). The result of the risk assessment is the economic estimates of the infrastructure project and the predicted probabilistic distribution of their values.

Below is a fragment (example) of the results of the risk assessment:

Probability distribution of the value of the internal rate of return





Variables affecting the net present value and the extent of their influence

The purpose of the work of the normative documents group is to prepare new and improve existing normative documents for the construction and maintenance of roads by applying the provisions of the normative documents of the EU countries suitable for the roads of the Republic of Lithuania in accordance with the climatic conditions and the existing legal framework.

We have prepared:

Analysis of road maintenance market prices and road maintenance methods
This document analyzes the unit rates and work methods of road maintenance works performed by state-owned road maintenance companies, as well as the unit rates of other companies that perform road maintenance works on behalf of municipalities. Market price comparison data were presented, according to which it was proposed to continue to use the fixed amount for the final result according to the established level of maintenance method on roads of national importance as a cheaper way to maintain roads.

Recommendations R IGGT 14 for engineering geological and geotechnical and structural investigations of automobile roads.
Recommendations R IGGT 14 apply to roads and streets of state significance of the Republic of Lithuania, which are a continuation of state roads. The recommendations contain the necessary engineering geological and geotechnical studies for the selection of the road route and the creation of a special plan, for the preparation of projects for new and reconstructed (repaired) roads and streets, bridges, other road structures, as well as the necessary studies for roads and streets, bridges, other road structures for designing structures in the karst region of Northern Lithuania.

Part I of the road maintenance manual “Automotive road maintenance regulations KPV PN-14”
This is the basis of the automotive road maintenance management system – part of the KPV set. The regulations apply to the technical maintenance of roads and streets of state significance of the Republic of Lithuania, which are continuations of state roads. The regulations are intended for the personnel of state enterprises performing technical maintenance of roads, as well as for all legal and natural persons maintaining roads of state importance. The regulations are intended to guide when determining the levels of technical maintenance of roads of state importance, performing works and checking the quality of works.

Adjustment of normative documents was carried out:

Part II of the road maintenance manual “Technology of performance of road maintenance work for automobiles KPV DT-14” The
manual applies to road technical supervisors, i.e. state companies performing mandatory maintenance work on roads of state importance, road maintenance inspectors performing maintenance control, contractors performing maintenance work to create cost norms (according to the submitted work descriptions), to prepare a set of norms for the costs of labor, mechanisms and materials for road maintenance works.

The set of labor, machinery and material cost norms for road maintenance works DMMS-KP 14″
The cost norms presented in the set are used to determine the calculated value of permanent and periodic (minor repair) road maintenance works on state roads and streets that are a continuation of state roads.

The cost norms have been revised, taking into account the requirements for the installation of roads of state importance, the new products and mechanisms used in construction, as well as the experience of road maintenance companies, the new normative documents used in practice and the recommended cost norms for determining the value of structural maintenance works. Cost norms have also been prepared, taking into account their wider application to the development of calculation programs.

Part III of the road maintenance manual “Economic norms for road maintenance and repair KPV EN-15” The
manual applies to the implementation of the financing of the Road Maintenance and Development Program, to the institution responsible for the preparation of financing to determine and substantiate the estimates of the use of funding funds for the next year’s program (the road maintenance part of national significance) project, as well as for state enterprises and other legal or natural persons maintaining roads of state importance, to plan the funds necessary for maintenance in accordance with the instructions of Part IV of the Road Maintenance Manual “Preparation, technical control, acceptance and payment of the program of automobile road maintenance works KPV TKDP-15”.