Beam intersection sensors 

Beam-crossing sensor gates provide a relatively low-cost solution for collecting traffic volume data on a measured path. They have been used as an alternative to the results collected from cameras, in places where it was difficult to analyze the traffic on a particular section of the path based on the surveillance image. The measurements record the time of sensor obscuration and the duration of the beam interruption. The idea was that the sensors would provide information on the volume of vehicle and pedestrian traffic, broken down by time of day and individual days of the week (link to solution concepts subpage). 

For the temporary installation of the sensor system, they were installed on wooden frames. The system consisted of the sensors, together with a control and data storage system on an SD memory stick and batteries to allow easy handling of the sensor-emitter pair. The height of the sensor from ground level was approximately 80 cm to detect pedestrians, wheelchair users and vehicles.

On 15 December 2021, preliminary tests were performed on the optical sensors under target operating conditions, which consisted of: 

• verification of permissible deviations during assembly,

• confirmation of the range of correct operation of the sensors,

• verification of the correct operation of the system in external conditions.

Fig. 2.  Photos from tests carried out in the target location

One of the problems that arose during the first series of surveys was that some of the sensors were blocked and obscured for long periods by parked cars. For this reason, the most favourable and non-conflicting locations were determined, together with signage of the measurement sites and information on the duration of the long-term measurements.

Fig. 3. Designation of measuring places