Process for detecting a user terminal (UT) in the passenger compartment of an articulated bus , the articulated bus comprising at least two units adapted for pivoting with respect to each other, said at least two units comprising a first unit and a second unit , a passenger compartment extending at least in the first unit and in the second unit , the process comprising the step: obtaining position data of a user terminal (UT), said user terminal (UT) being outside the first unit , wherein the process further comprises the steps: computing inclination information of the second unit with respect to the first unit , wherein the inclination information comprises an inclination angle (α ; β) formed by the units and/or the position of a reference point (RP) of the second unit with respect to the first unit , computing the shape of the passenger compartment by using information comprising the inclination information and the known geometry of each unit , wherein said shape comprises at least one of the following: the outline of the passenger compartment , the volume of the passenger compartment , and the longitudinal central line (LCA) of at least one of the units , assessing whether the user terminal (UT) is inside the second unit , by comparing the position data of the user terminal (UT), and the space covered by the computed shape of the passenger compartment . obtaining position data of a user terminal (UT), said user terminal (UT) being outside the first unit , wherein the process further comprises the steps: computing inclination information of the second unit with respect to the first unit , wherein the inclination information comprises an inclination angle (α ; β) formed by the units and/or the position of a reference point (RP) of the second unit with respect to the first unit , computing the shape of the passenger compartment by using information comprising the inclination information and the known geometry of each unit , wherein said shape comprises at least one of the following: the outline of the passenger compartment , the volume of the passenger compartment , and the longitudinal central line (LCA) of at least one of the units , assessing whether the user terminal (UT) is inside the second unit , by comparing the position data of the user terminal (UT), and the space covered by the computed shape of the passenger compartment . computing inclination information of the second unit with respect to the first unit , wherein the inclination information comprises an inclination angle (α ; β) formed by the units and/or the position of a reference point (RP) of the second unit with respect to the first unit , computing the shape of the passenger compartment by using information comprising the inclination information and the known geometry of each unit , wherein said shape comprises at least one of the following: the outline of the passenger compartment , the volume of the passenger compartment , and the longitudinal central line (LCA) of at least one of the units , assessing whether the user terminal (UT) is inside the second unit , by comparing the position data of the user terminal (UT), and the space covered by the computed shape of the passenger compartment . <EOS>