New Procedure Based on Obtaining the Average Deceleration for Improving the Spanish National Inspection of Tractor Service Brakes

Abstract

This study addresses the status and proposes key aspects relevant to refining of the procedure for the Spanish National Inspection of Vehicles relative to tractor service brakes, specifically focusing on obtaining the average deceleration. The current inspection method lacks a clear definition of the calculation process for average deceleration in the Spanish Official Manual of Procedures of Inspection of Vehicles. This lack of clarity results in varying outcomes and potential acceptance or rejection of the inspection based on the selected equipment and procedure. To address this issue, a comprehensive series of tests were conducted on different vehicles, using various equipment and calculation methods. The objective was to derive meaningful conclusions regarding the calculation method, measuring equipment, and other relevant factors. This study reveals the inadequacy of the current average deceleration calculation method as outlined in the official inspection manual. The findings highlight the crucial role of accurate equipment selection, appropriate calculation methods, and skilled personnel experience in ensuring reliable and consistent results. To address this, a new standardized procedure is proposed to streamline the process of obtaining the average deceleration in the inspection of tractor service brakes. The recommended procedure encompasses the use of a secure, well-defined track, clearly marked acceleration and braking points, a GPS decelerometer, a portable or on-track speedometer, and data processing that excludes the initial and final sections of the deceleration curve. Furthermore, this study highlights the need to update the acceptance thresholds for the inspection, as the current thresholds may no longer align with the proposed procedure. A revision of these thresholds is suggested to establish new criteria that are more appropriate and in line with the proposed method and for tractors manufactured after 01/01/2016.