At some intersections, the so-called detector mode of operation is applied, which introduced changes in signaling and created confusion among drivers.
“The duration of the yellow light for speeds up to 60 km/h is three seconds. For speeds over 60 km/h, the yellow light lasts four seconds. The yellow light in road work zones lasts four seconds. The yellow light at the same time as the red light lasts for two seconds. If a flashing light is used at the end of the green light term, it must last four seconds, so that the alternating on-off intervals last 0.5 seconds each. it is stated, among other things, in the Rulebook.
However, it creates the biggest confusion among drivers new detector system which includes sensors that detect when a car stops on them, i.e. pedestrian buttons, which were not very popular until now, and which led to change in signaling.
New rules at intersections
As explained to MONDO by the Secretariat of Traffic, the light signaling in Belgrade is designed to function in one of the following modes of operation: fixed operation, detector operation and adaptive operation.
“In detector work, as a rule, green time is assigned to a signal group in accordance with real-time requirements. With fixed operation, the green signal is assigned in a precisely defined period of the cycle, regardless of whether there are requests for servicing on the approach or not. This is also the essential difference between fixed and detector/adaptable systems”, they explain from the Secretariat for our portal.
In translation, citizens should know that detector traffic lights are adapted to the current needs on the ground, as well as that drivers should learn new rules of behavior at intersections where they were installed in the previous period.
With systems for adaptive traffic management, i.e. new traffic lights, data about what exactly is happening in real time is collected through detectors and adjustments are made to current needs. If there are more vehicles somewhere, the green light for those vehicles will last longer, and the pedestrian traffic light, for example, will remain red until a pedestrian comes by and presses the button on the traffic light pole. Only after that, in the next cycle will it turn green.
“The most common model of servicing detector signal groups is as follows: if there is a registered vehicle announcement for the signal group, the signal group is assigned a minimum green time (e.g. for 10 seconds), and then based on the registered vehicle announcements on the relevant detectors, a decision is made to extend green signal. The extension can last: until the fulfillment of the maximum set value for the green signal on the specific signal group; until reaching a certain point in the cycle or until an overrun occurs in the tracking interval between vehicles on the detectors”they explain to MONDO in the Secretariat for Transport.
As they further state, the green signal is interrupted due to exceeding the tracking interval between vehicles on the detectors in a situation when a free interval appears on all detectors that control the duration of the green light on a specific signal group, an interval without vehicles longer than the set value (most often three to four seconds). .
Flashing green depends on the traffic lights
When it comes to the flashing green light that our drivers are used to, the Traffic Secretariat explained to us that it remains at intersections where a fixed work system is applied, while such a light is not turned on with the new systems.
“In Belgrade, it is very important that the time at the traffic lights is used rationally, at intersections with detector operation or in the adaptive management system, which are located within the city area where the speed is limited to 50 km/h, and a model of the functioning of light traffic signals has been adopted without turning on the flashing green interval in transition states”, they state in the Secretariat.
On the other hand, as they add, at the intersections with “fixed time” signal programs switching on/off the flashing green depends on the technical capabilities of the traffic light device.
“The problem associated with the flashing green for four seconds is related to the different response of drivers to the appearance of the green flashing signal. Some drivers use this interval to accelerate and pass over the stop line, while some drivers after activating this signal slow down the movement of the vehicle, with the intention of stopping at the stop line. Even more drastic is the problem of the driver’s reaction after the second or third flashing of the green light. So that moment is also taken into account when designing the light signaling on a road.” said the authorities for our portal.
(World)