Most (60%) documented effects of roads on animal population abundance are negative. However, some animal populations appear to be unaffected or even increase in response to roads. Neutral and positive effects represent up to 29% and 24% of all effects, respectively, suggesting that not all populations or species are equally vulnerable to road-induced population reductions. Prey species may show neutral or positive responses to roads if roads reduce their predator populations. Roads can also provide a range of resources for many species, such as roadside habitats for small mammals and insects, and road-killed food for scavengers. These resources may lead to increased reproduction and potentially to larger populations, particularly if the species can avoid being killed by vehicles. On the other hand, the resources provided by roads can create an ecological trap if the species cannot avoid being killed by vehicles. Understanding the conditions leading to neutral and positive responses to roads is critical to the identification of situations where mitigation of road impacts is not necessary.