Marathon on Maratońska Street: Simulating future traffic in Lodz

Maratońska Street serves as the main connection between the western part of Lodz, Poland’s fourth largest city, and the S14 expressway, a roadway that connects the area with the rest of the country along a north-south axis and locally serves as an external city bypass. Due to its key function and the nearby industrial areas, the traffic volume along Maratońska is already quite significant, even during off-peak hours.

With plans to expand the industrial footprint in the area, the city decided to conduct a comprehensive simulation analysis using PTV Group’s tools and engineering expertise. For microsimulation, the Dynamic Assignment feature was chosen to enable realistic route selection based on varying traffic patterns.

Current situation

As a regional capital, Lodz is located near the geographic center of the country, about an hour from the capital, Warsaw. Historically a center of the textile industry, Lodz earned the nickname “The Polish Manchester” in the 19th century. Today, many old factories have been converted into cultural and commercial spaces. Lodz is also recognized as a UNESCO City of Film, attracting international festivals and boasting the longest shopping street in Europe.

From a transportation perspective, Lodz is well-connected by rail and road, and is surrounded by highways and expressways that serve as bypasses for the city. Until recently, only the western side of the city lacked a bypass – this was solved by the introduction of the S14, which is now fully operational.

One of the main routes to the S14 is via Maratońska Street, a 7-kilometer road that connects the inner-city bypass with neighborhoods and industrial areas up to the expressway. Due to its strategic role, Maratońska carries a variety of traffic types and a high volume of traffic throughout the day, especially heavy goods traffic.

A short section of Maratońska has recently been upgraded to meet the requirements of the S14 junction, but traffic remains challenging due to early shift start times in nearby industries, resulting in up to six hours of high traffic volumes per day.

Traffic to and from the industrial zone primarily flows along Golfowa Street, a narrow two-lane road that is not designed to handle this volume. With over 4,000 jobs currently located in the area and plans to expand to as many as 10,000 jobs, the city identified an urgent need for in-depth analysis.

Simulation goals

From the start, the plan was to perform both strategic and microsimulation analyses:

PTV Visum strategic simulation would help estimate new traffic volumes and delays associated with the industrial expansion.

PTV Vissim microsimulation would then test detailed design changes, focusing on the introduction of an alternative route to relieve Golfowa Street. Dynamic Assignment in PTV Vissim was essential to accurately model route choice based on changing traffic conditions.

Strategic analysis with PTV visum

Lodz has a long history of strategic modeling, and local experts regularly update city models. The latest model, using 2022 traffic data for AM and PM peak scenarios, predicted conditions for 2025 and 2030. For this analysis, detailed road networks were added to the model. Once the current year was calibrated, it was ready for future scenario testing.

Scenarios of future demand and network deployment

The city estimated the expansion potential in the new production area to 330,000 m², with job estimates between 1,160 and 6,400, based on different industry-to-logistics mixes.

The critical value was directly implemented into the existing strategic model of the City of Lodz, leading to the production of new forecast scenarios for the year 2030.

Three scenarios of network development were modeled:

Scenario 1: Do nothing – the road network remains the same,

Scenario 2: Expansion – Maratońska to four lanes and redesign of a critical intersection as a turbo roundabout.

Scenario 3: Expanded Scenario – expanding Scenario 2 with a new road link and upgrading the existing roundabout at the S-14 junction to a turbo roundabout.

Results of Visum simulations

Scenario 1 showed that the current shape of Maratońska Street is not sufficient, leading to significant delays and worsening traffic conditions.

Scenario 2 offered partial improvement, but didn’t solve all problems.

Then, Scenario 3 provided a noticeable improvement in all aspects of the main Maratońska Street and all adjacent roads, but unfortunately it was the costliest.

Therefore, further analysis was performed in the detailed environment of PTV Vissim. Therefore, each PTV Visum model was sub-generated to the direct area of interest for further analysis in PTV Vissim.

Microsimulation with PTV Vissim

Once the strategic forecasts were complete, PTV Vissim was used to create an accurate microsimulation of Maratońska and the surrounding area.

Calibrated to 2022 conditions, the model tested forecast scenarios for 2030. All scenarios used Dynamic Assignment, PTV Vissim’s robust route selection method, which allowed estimating the influence of possible route choices in the simulated area, a crucial factor especially for scenario 3. 

Scenario 3, using Dynamic Assignment, showed that the new link road significantly reduced congestion on Golfowa Street. Dynamic Assignment, unlike Static Assignment, allows paths to be adjusted based on real-time delays and cost perspectives, providing more realistic route-choice behavior.

Once the strategic forecasts were complete, PTV Vissim was used to create an accurate microsimulation of Maratońska and the surrounding area, including the industrial park and highway interchange. Using demand derived from strategic forecasts, it was possible to recreate and further analyze possible outcomes.

Unlike the classic Static Assignment in PTV Vissim, Dynamic Assignment requires a matrix or series of matrices representing the trips between specific edges of the modeled area, and allows dynamic route selection based on iterative best-path searches. This method accounts for delays and traveler costs, making it ideal for testing alternative routes such as those in Scenario 3. For consistency, Dynamic Mapping was used across all scenarios.

Results of Vissim simulations

The results confirm the initial picture from the strategic simulation.

Scenario 1 resulted in severe delays with significant queuing phenomena in many sections of the network, including Maratońska and Golfowa.

In Scenario 2, the introduction of a new roundabout and the widening of Maratońska to 4 lanes in each direction improved traffic conditions, but delays and queues weren’t eliminated.

Scenario 3, which acts as a further extension of Scenario 2 with the new link connected to the introduced turbo roundabout, showed the best results in traffic flow improvement, providing a network design that meets future demand. Below, selected results show the difference between the scenarios for the AM peak hour.

Conclusion

Lodz, Poland is tackling congestion on Maratońska Street, a major route to the S14 highway, as industrial growth increases traffic demand.

The city used PTV Visum to model strategic scenarios to forecast traffic volumes and test potential improvements, including road expansions and new links.

PTV Vissim microsimulation, with its Dynamic Assignment feature, then analyzed realistic route choices based on varying traffic conditions, confirming that adding a new link road and a turbo roundabout would effectively reduce congestion.

Based on these findings, Lodz is moving forward with targeted infrastructure upgrades to meet future needs.