Janusz Gajda

Janusz Gajda received his Master’s, PhD and post-doctoral degree and the title of the Professor in 1978, 1985, 1993 and 2001, respectively, in the field of engineering sciences and in the discipline of electrical engineering. He is currently employed as a professor in the Department of Measurement and Electronics at the AGH University of Science and Technology in Krakow. His areas of interest are: electrical and electronic metrology, object identification, signal processing, traffic parameter measurements, and biomedical measurements. He is the author of over 250 scientific publications, including 7 books and 5 patents. He has promoted 5 doctoral students.

From 1999 to 2016 he headed the Department of Measurement and Electronics at the Faculty of EAIiIB, AGH. Since 2016, he has been the Vice Dean for Science at the Faculty of Electrical Engineering, Automation, Computer Science and Biomedical Engineering (EAIiIB). Since 2007 he has been a member of the Committee on Scientific Metrology and Apparatus of the Polish Academy of Sciences, and since 2016 he has been the Chairman of this Committee. Since 2017 he is a member of the Council of Metrology at the President of the Central Office of Measures. He is an Expert of the Commission for the Evaluation of Science in 2022. He has been a member of the International Society of Weigh In Motion since 2008.

He has been awarded Silver and Gold Cross of Merit, Knight's Cross of the Order of Polonia Restituta, National Education Medal, Gold Medal for Many Years of Service, Paweł Jan Nowacki Medal, 85th Jubilee Medal of AGH, 50th Jubilee Medal of AGH Department of Measurement. He received 5 Gold and 7 Silver Medals at the International Invention Fairs in Warsaw, Seoul, Brussels and Geneva. He has been repeatedly awarded by the Rector of AGH for scientific, didactic and organizational achievements.

DYNAMIC ADMINISTRATIVE WEIGHING OF MOTOR VEHICLES

The development of road transport of people and goods observed around the world, including Poland and other European countries, has resulted in the need for effective control of the weight of vehicles on the road and the elimination of overloaded vehicles. Overloaded vehicles cause a threat to the safety of road traffic participants, as well as significantly accelerate the process of destruction of road infrastructure, threaten the environment and violate the principles of fair competition in transport. 

The system for controlling the weight of motor vehicles is currently based primarily on "manual" weighing of vehicles on static or slow-transit scales. The authority entitled to carry out such inspections in Poland is the Road Transport Inspection (ITD). The inspection procedure is time-consuming. Each controlled vehicle is stopped and directed to the weighing station. The duration of an inspection of a single vehicle can exceed 60 minutes, which makes the system inefficient.

In parallel, there has been technical development of dynamic vehicle weighing systems called Weigh-In-Motion (WIM) systems. WIM systems are usually built as a pair of sensors or a system of multiple pressure sensors mounted in a lane, in the road surface. The sensors work in conjunction with a computer system that implements an algorithm to estimate the weight of the vehicle and the static pressure exerted on the ground by each axle. The quantity to which the pressure sensors directly respond, on the other hand, is the dynamic pressure exerted on the ground by the wheels of the axle that is currently above the sensor. The idea behind WIM systems is fairly simple. Problems arise when we start striving for high and stable accuracy of the resulting weighing result. The causes limiting this accuracy are many and, depending on their source, can be divided into three groups:

Factors related to the vehicle being weighed:

• vertical vehicle fluctuations,
• the speed and change in speed of the vehicle as it passes through the WIM stand,
• the air elevator effect depending on wind speed and direction.

Factors related to the road surface:

• broadly defined road quality,
• spatial repeatability of axle load,
• change in pavement parameters due to changes in temperature and other environmental factors.

Factors related to the WIM system:

• the number and technology of pressure sensors used,
• the method of their installation and distribution along the WIM stand,
• speed measurement error,
• accuracy and frequency of system calibration.

Such a numerous set of factors interfering with the measurement of WIM systems means that these systems currently play a very important, but only auxiliary, role in detecting overloaded vehicles. Namely, they work as preselection systems, making it easier for ITD inspectors to type vehicles headed for "manual" inspection. This undoubtedly contributes to a certain improvement in the efficiency of the inspections carried out, which, however, is still unsatisfactory.

The current direction of development of WIM systems is aimed at leading to a state in which it will be possible to directly use the weighing results, obtained with their help, for administrative actions aimed at enforcing the regulations in force in the field of road transport. Such systems are called administrative WIM systems. Research, legislative and legal metrology work aimed at implementing administrative WIM systems is also being carried out in Poland.

The advantage of implementing the administrative WIM systems into practical use is the continuous weight control of all vehicles passing through the WIM station. Weighing would take place 24/7, regardless of season and weather. The weighing process would not cause traffic disruptions and would not involve traffic users in terms of time.

Implementation of administrative WIM systems requires solving problems located in three areas:

• research area: ensuring stable, known and possibly high weighing accuracy (total weight, axle load
• legislative area: introduction of relevant legal regulations, enabling administrative use of WIM systems
• legal metrology area: development of documents for metrological legalization of WIM systems.

This paper presents the directions and results of research work conducted in Poland to ensure the highest possible and known accuracy of WIM systems running under changing operating conditions.