Transport is one of the most environmentally destructive branches of economy. It contributes to environmental degradation and influences negatively on human live. It should therefore seek to reduce the negative impact on the environment. The paper presents many aspects of development of the national transport system. In article characterized technical constraints and environmental issues, which are applicable to the designing of pro-ecological transport system. Presented in it also indicators of the proposed design solution quality.In shaping the pro-ecological system the special role plays environmental restrictions, because they mainly determine the quality of solutions in terms of minimizing the negative impact of transport on the environment. Technical factors are equally important, because they allow, among others, reducing the external costs of congestions and allow on the creation of transport tasks on the appropriate level. In particularly, EU requirements for sustainable development of the transport system, the components of the external costs arising from the sphere of transport, indicators and ecological limitations in designing of pro-ecological transport system, ecological limitations, technical limitations, indicators for assessing pro-ecological transport system are presented in the paper.