This work presents the results of an experimental study of the braking properties of bicycles and an e-bicycle. Data on braking decelerations and braking distance under different braking conditions were obtained for different bicycles including an e-bicycle. A satellite receiver was used to receive the data and specialized software was used for their processing. The specialized literature lacks data on the braking properties of bicycles for Bulgarian road conditions, which are necessary for any expert investigations of accidents involving cyclists. An initial database of bicycle braking decelerations for various braking conditions was compiled. The obtained results on the braking properties should be very useful in the preparation of auto-technical examinations for the court and the police, as well as for improvements in road traffic safety.

This paper presents the results of an experimental study of the influence of the mass of the load on the variation of the longitudinal braking deceleration of a semitrailer truck. Data were also obtained on the magnitude of braking decelerations under specific conditions. When investigating road accidents in the conditions of Bulgaria, no data are available in the specialized literature on the maximum braking decelerations of semi-trailer trucks, and the same can be said of the influence of the full mass of the vehicle on the braking properties. Such data are extremely important in expert evaluation of court cases. Traffic safety is one of the main factors for preserving human health and life. Bulgaria has a relatively high number of deaths as a result of traffic accidents among countries in the European Union. Thus, the problem is very relevant for this country. One of the main factors determining traffic safety is the braking properties of vehicles and, more specifically, the braking deceleration.

The study addresses the challenge of accurately simulating and visualising the kinematics of agricultural machinery during field operations. The research is motivated by the current lack of comprehensive guidelines for selecting optimal movement and turning modes under varying forward speeds, working widths, and field geometries. A spreadsheet-based environment was utilised to perform simultaneous kinematic simulation and trajectory visualisation. Turning manoeuvres were modelled using smooth composite curves, consisting of straight segments, clothoids, and circular arcs, with trajectories represented in a Cartesian coordinate system through geometric transformations including translation, rotation, and mirror symmetry. Continuity between curve elements was ensured by dimensional chains linking abscissas, ordinates, and direction angles at their start and end points. The influence of key operational factors—forward speed, angular turning velocity, working direction, and field boundaries—was evaluated for a range of turn types, including semicircle, pear-shaped, figure-eight, side exit, U-turn, and P-turn manoeuvres. Field experiments conducted on selected patterns confirmed that the proposed approach can reproduce actual trajectories with sufficient practical accuracy. These results demonstrate that spreadsheet-based kinematic modelling is a robust and accessible tool for optimising tractor–implement movement, enhancing operational planning, and providing a reliable framework for further research into machinery performance under complex field conditions.