Professors from the Faculty of Civil Engineering at the University of Sarajevo, Suada Sulejmanovic and Ammar Saric, looked at the problem of traffic jams in the capital and analyzed current solutions in the traffic infrastructure.
In the analysis, the professors emphasize that increasing traffic jams are often justified by the uncontrolled construction of a large number of residential buildings, then construction work on the road infrastructure, poor public transport, but there is no mention of the mistakes caused by investing in the wrong traffic solutions that, instead of solving, actually worsen traffic congestion.
“It is often misinterpreted by the public that roundabouts serve to ‘accelerate’ traffic. However, this is not always the case,” the professors said, citing the Energoinvest-Pofalici, Buca Potok, Quadrant-Cengic Vila intersections as examples.
Fake sidewalk
In the text about traffic jams and other problems, professors from the Faculty of Civil Engineering also referred to pedestrians who walk on the footpath of the island at the roundabout.
“Namely, along the central island, a footing (driveway) section is often designed, which, together with the circular traffic lane, allows longer vehicles (trucks) to pass through the intersection. It is slightly elevated in relation to the traffic lane so that it is not used by drivers of passenger vehicles. This section differs in construction from a circular road lane mostly by the color and application of different materials, such as, for example, a stone cube,“ it is explained.
Roundabouts (do not) solve all traffic problems
In the current engineering practice in Bosnia and Herzegovina(BiH), as well as among different levels of government, there is currently a general opinion that all traffic problems are solved with traffic intersections.
“It is less known that the reconstruction of any intersection is preceded by the process of planning and analysis of traffic flows, and only then the design. As in most other areas, the practice in BiH is somewhat different: planning and analysis of traffic flows are regularly omitted (forgotten), and that is why a large number of roundabouts were built incorrectly or unnecessarily”, they explain.
They emphasize that the analysis of traffic flows in a broader sense implies the collection of data on the existing traffic load, the structure of the traffic flow, the number of pedestrians and cyclists, the number of traffic accidents, the position and role of the intersection in the wider traffic network, and the calculation of the basic functional indicators of each intersection: capacity, delay time, the level of service and the length of the queue at the entrance.
Can seven lanes fit more vehicles than 13?
They also point out that the reconstruction of the “Energoinvest” intersection in Sarajevo is a glaring example of the wrong choice of intersection type.
“Originally, there was a classic intersection with traffic lights at this place. In 2020, it was reconstructed into a two-lane roundabout, with two entrance and two exit lanes on three access roads, and one entrance and exit on the fourth. When calculating the capacity of intersections, the entrance lane capacity is taken into account. Even if we are not experts, it is enough to count the entrance lanes and get an initial idea of which type of intersection is more favorable. In the specific case, the original intersection with traffic lights had 13 input lanes, and the existing roundabout has 7,” they emphasized.
The logical question arises, they point out, can more vehicles fit in 7 lanes than in 13?
Finally, it is clarified that the newly built roundabout not only did not solve the existing problems but also generated additional traffic problems, Klix.ba reports.
E.Dz.
