A method that employed a mathematical model of the braking system and a Genetic Algorithm was developed to find the test set-up that allowed a user-define deceleration pulse to be obtained. Using this method it was found out that none of the feasible set-ups of the braking system was able to reproduce the deceleration pulse required. The tests confirmed this and highlighted the need for improvement in the initial design of the braking system. During the tests, it was also observed that there was significant wear of the constraint system due to friction between the beams and constraints. In order to reduce wear, roller bearings were implemented. As a result the braking performance of the system was drastically reduced. In an effort to improve the efficiency of the braking system so that it could be used to carry out tests according to the specifications for small airplane seat certification a new layout for the constraint system was developed and pre-deformed deceleration beams were used. In parallel, a new seagull-wing shape trolley was designed to reduce vibration and moments transferred by the hooking system to the test article. Eventually, the braking system was put into full operational service and is currently used to carry out various tests with the prescribed deceleration pulse. The tests carried out so far, in particular, have shown the reliability of the system. The tests provide repeatable results. The braking system is easy to use, inexpensive to manage and maintain. It is characterized by the almost complete absence of vibration and negligible elastic energy restitution and trolley rebound. Tests with a prescribed acceleration pulse are fundamental for the development of crashworthy structures and mandatory for certification of various components such as aircraft and sports car seats and restraint systems. At the Politecnico di Milano Laboratory for the Safety of Transports tests with a prescribed deceleration pulse are carried out using a Horizontal Impact Sled Facility. A new braking system designed to obtain prescribed, user-defined deceleration pulses was developed. The guiding idea in its development was to arrest the trolley or sled running on rails by means of a number of bending beams having variable lengths and placed at variable distances from each other. Static and dynamic tests were initially carried out to verify the feasibility of this idea. Then, the data collected from the tests were used to validate a Finite Element model that was in turn used to develop the braking system. A fully operative braking system was built and its performance evaluated by reference to the specifications for the test for small airplane seat certification.