The Quantification of Operational Reliability of Agricultural Tractors with the Competing Risks Method

Reliability is one of basic parameters affecting the decision to purchase a new or used farming machine. However, there are no objective rankings of the probability of farming machine failures after any period of operation. This article presents an innovative method of quantifying the reliability of farm tractors. The method is so universal that it can also be applied to other farm vehicles and machines. Bernoulli's competing risks method enables precise indication of the right probability distribution (exponential or Weibull) on the basis of the number of identified random and age-related failures. The method was verified logically and empirically. The validation was based on the data collected from long-term users of farm tractors in Poland. Massey Ferguson tractors were found to have the best relative reliability index. This result justified the high sales of Massey Ferguson products in Europe. According to the data for 2020, they were ranked in the top three in Lithuania, Norway, and Sweden.