The general aim of this thesis is to present and analyse traffic safety from an ethical perspective and to explore some conceptual and normative aspects of moral responsibility. Paper I presents eight ethical problem areas that should be further analysed in relation to traffic safety. Paper II is focused on the question of who is responsible for traffic safety, taking the distribution of responsibility adopted through the Swedish policy called Vision Zero as its starting point. It is argued that a (...) distinction should be made between backwardlooking and forward-looking responsibility and that Vision Zero should be understood in terms of this distinction. Paper III discusses responsibility ascriptions in relation to public health problems like obesity and lung cancer. It is argued that what makes discussions about who is responsible for such problems complicated is that we have two aims when ascribing responsibility to someone. First, we want responsibility ascriptions to be fair and morally justified. Second, we also want to achieve progress and solve problems through ascribing responsibility to someone. It is argued that the two aims influence debates concerning who is responsible for problems like obesity and lung cancer and that we should attempt at striking a balance that is both perceived as fair and that is efficient. Paper IV discusses two potential arguments against the suggestion that alcohol interlocks should be mandatory in all cars, namely 1) that it displaces the responsibility of individual drivers, and 2) that it constitutes a paternalistic interference with drivers. The first objection is found unconvincing, while the second only has limited bite and may be neutralized if paternalism is accepted for the sake of greater net liberty. It is argued that if technological development can make mandatory interlocks cost-efficient, the policy seems a commendable public health measure. In Paper V, the question discussed is to what extent individuals should be ascribed moral responsibility for the environmentally damaging consequences of their actions. It is argued that responsibility depends on the reasonableness of the alternatives open to an individual when acting. The lack of reasonable alternatives should reduce the degree of individual responsibility. (shrink)