In the 70’s, to reduce vehicle crash fatalities, NHTSA launched a Program, called NCAP, to compare the safety of cars. This Program was copied in Europe and around the world. It has been demonstrated that this kind of public assessment has forced OEM’s to invest in safety and to develop safer vehicles. Nowadays, NCAPs exist for nearly all regions around the world; all of them with the aim of improving vehicle safety. They apply the philosophy of an “overall rating”. In that way the information aims to be clearer and more general and will help to compare cars. Nevertheless, even though in every NCAP the overall assessment is given by a unique star rating, the specifications and requirements in each protocol are different. Each NCAP has been adapted to each region’s conditions, accidentology and traffic and therefore assessment criteria have their own peculiarities. Accordingly, differences in ratings may have significant consequences for the design of the vehicle’s equipment or structure. A general study about the differences in NCAPs around the world has been carried out. In this paper, the protocols’ requirements and specifications used in each test will be presented and described for each NCAP program. Furthermore, NCAP assessments are constantly changing and becoming more and more challenging using new dummies, following new test protocols, introducing active safety systems or rear seat evaluations. The evolution of the protocols will also be presented and special attention will be devoted to the current and future protocols with the new requirements added.