Seven out of ten intersections in Warsaw through which trams pass are equipped with a green wave, i.e. a modern system thanks to which they do not have to wait for a green light – Warsaw Trams boast about the solution. According to tram drivers, this number is still growing. Ultimately, the green wave will cover 90 percent of intersections in the capital.
As calculated by Tramwaje Warszawskie, already 187 intersections in Warsaw through which trams pass are equipped with the green wave system. This is 71 percent of all intersections. “Ultimately, as many as 90 percent of them will be covered by this system. This number is constantly growing, because in 2021, the priority of passage for vehicles on urban tracks was in force at over 60 percent of intersections. This will also be the case on all new tram routes – to Gagarina, to Wilanów and along Kasprzak. Intersections on these routes are designed immediately with priority for trams, “said in a communiqué on this subject.
Green wave. How it works?
How does the tram green wave work? Approaching the intersection, the tram passes through a sensor that “sends” information to the traffic light control system. The system is activated by an algorithm designed by engineers from Tramwaje Warszawskie. As they explained, it works in such a way that the tram does not stop at the red light or the green light turns on faster. When designing a control algorithm for a specific intersection, this system is first checked in the virtual world. Later, in the first period after implementation, the performance of the algorithm is monitored in detail in the field and corrected if necessary.
The new system is created under the care of city road workers and is monitored by them, thanks to which the communication needs of other traffic participants – pedestrians and drivers – are also taken into account.
As we read further in the release, for two years Tramwaje Warszawskie, as the only one in Poland and one of the few in the world, has been using a priority for trams based on a satellite navigation system (GPS) and data processing in the cloud. Tram operators are moving away from technology that requires underground wiring to virtual tram sensing systems. Until recently, the introduction of the green wave required the installation of sensors. They detected approaching trams – from a distance of up to several hundred meters. This involved the need to lay underground installations and dig up the streets. The cost of building such an installation at one intersection amounted to several hundred thousand zlotys. The new system based on virtual tram detection saves these amounts.
Shorter travel time and savings
Thanks to the green wave for trams, the travel time on many lines has been shortened. One of the best examples is line number 17, which takes 24 minutes from Białołęka to the Marymont metro station today. Before switching on the priority, the tram covered this 11-kilometer section by 8 minutes longer. The communication speed of the “seventeen” – calculated together with stops at stops – increased from 21 to 28 km/h. In turn, line number 2 (from Winnica to the Młociny metro station) is now 5 minutes shorter, which means that the journey time is shortened by as much as a quarter. Trams on “two” reach a communication speed of about 30 km/h, making it one of the fastest lines in Poland. From 41 to 33 minutes, the travel time of line 1 between Annopol and Plac Zawiszy was shortened. Line 23 from Nowy Bemowo to Praga has also accelerated, now taking 35 minutes, earlier – 45 minutes.
The tram green wave also brings benefits for the city budget. – We can make the same number of journeys with fewer wagons. Since the beginning of the changes, it has been possible to “recover” not only as many as 36 trams, but also 108 jobs to operate them. These are real savings for Warsaw Trams, but more importantly – for passengers and the city’s budget – says Wojciech Bartelski, president of Warsaw Trams quoted in the release.
The research of tram drivers showed that when the green wave was “turned on” on ul. Marymoncka, the energy consumption of trams decreased by 13 percent on this section. Only on this one line, savings during the year reached PLN 200,000.
Main photo source: Warsaw Trams