Several transportation problems, as well as problems in other knowledge areas, request decision making. In complex decisions, the choice of best alternative or course of action can contain more than one criterion and it is necessary to study how each alternative affects each criterion. The AHP, Analytic Hierarchy Process, proposed by Thomas L. Saaty, is a multicriteria decision method that works well for very diverse decision types, solving problems with tangible and intangible factors. It gathers the opinion of decision makers in comparison matrices. This study makes a general review of basic concepts of the method, showing different manners of calculating the solution. The first one to be displayed is the exact solution using the eigenvalues and eigenvectors of the matrices. For this solution the French software Scilab was used, which is similar to the well-known Matlab, but free and distributed on the web. The issue of judgment consistency is discussed, including ways of measuring and improving it. Finally, a proposal of approximated solution is made, questioning the original idea which says that a certain level of inconsistency is desirable. It is a simplification that, considering absolute consistency, facilitates not only the calculations but also the early work of decision makers when judging the alternatives. Instead of making pair wise comparisons of all alternatives with each other, it becomes necessary to compare only one alternative with the others. The new approximated solution is compared to the real solution in three cases taken from the literature.