ABSTRACT This thesis has been developed with the aim of the development of a new design model of the deceleration lanes length, based on evaluation of the design and operation of the parallel deceleration lanes, depending on its length, by development and implementation of a new conflict indicator for exiting maneuvers. This aim has emerged from the study of the state of the art which stands out that Kinematic models of uniform deceleration, which are usually adopted for designing deceleration lanes, do not correspond with experimental observations carried out by various researchers. The research was based on the fundamental assumption that the behavior of drivers who take a deceleration lane varies depending on the deceleration lane length. This behavior change affects the operation of deceleration lanes and therefore influences road safety. The research development has two phases. The first is a experimental phase in a parallel deceleration lane changing its length. In the second phase was carried out to validate results by observing 10 additional deceleration lanes. In both, a qualitative analysis was performed by video observation and a quantitative analysis which sought to measure the characteristics of the vehicles evolution. To achieve this, a computer software for restitution of conical perspective from videos was developed. It allows us to tracking individual vehicles at all frames and know their position, speed and acceleration rates. In order to properly assess the various maneuvers found, it was decided to use for the quantitative evaluation, the Traffic Conflict Techniques. Such techniques allow us to assess road safety based on time-space measures between vehicles and with the use of conflict indicators. To do this, it was necessary to developed and validate a new conflict indicator applicable on exit maneuvers. Indicator called TiPCLA (Potential Time to Rear end or Lateral Collision) was developed. It has allowed a quantitative assessment of the conflict of deceleration lanes of the study. Based on the results analysis, the working hypothesis was confirmed. It was possible to conclude that too long or too short deceleration lanes are less safer. The optimal are intermediate length. Finally, a new design model for parallel deceleration lane length was developed. This model takes into account both the dynamics of the exit maneuver, as the drivers behavior and road safety.