Strategic Environmental Assessment (SEA) has become recognised as an improvement on the existing, limited system of project-based EIA. It aims to integrate environmental considerations into government policies, plans and programmes, and provides a basis for arriving at better-informed decisions at broader strategic levels. However, the compatibility of this new environmental planning tool with other planning systems such as transport, holds the key to successful integration of environmental concerns into existing planning approaches. This study investigates whether SEA can influence and integrate with transport planning and policy development processes through a survey of attitudes and opinions of planners on transport SEA in Taiwan. Transport planning has been criticised for considering too few alternatives, and for basing evaluations solely on technical and economic grounds. The emerging SEA seems theoretically feasible and potentially beneficial in allowing the integration of environmental concerns into strategic transport planning. Though many countries or regions have transport SEA provisions, practical transport SEA applications remain limited, mostly in Western developed countries with high environmental awareness. SEA applications are also limited in their strategies, focusing mainly on infrastructure-related projects. Moreover, most current transport SEA practices lack strategic focus and thus fail to fulfill SEA principles. This suggests that many planners are unfamiliar with the nature and techniques of SEA, and the conceptual impediments are still critical, which may result in significant barriers to transport SEA application. The EIA Act promulgated in 1994, together with its relevant provisions, have provided an applicable mechanism and a legal basis for SEA application in Taiwan, however, no transport SEA cases have been conducted. Many technical and non-technical barriers have been identified by the interviewees, indicating that most of the planners in Taiwan believe that transport SEA is conceptually and practically immature, and planners are not yet ready for it. The conceptual barriers seem more critical at this stage because practical barriers can only be identified and overcome when planners and decision-makers have a clear and proper concept of SEA. This narrowly-viewed application has limited the benefits of SEA, and has resulted in a rigid and incorrect idea that SEA was a passive impact-reducing mechanism; this may mislead the attitudes of planners to transport SEA. In fact, the emerging SEA is a re-engineered planning system framework that serves to remind planners that they are able to improve their efforts. It is a paradigm revolution, as the way in which planners think can make a vast difference. Thus, the potential for the emerging SEA concept to influence and integrate with transport planning and transport policy development processes depends not only on practical feasibility but also on a fundamental conceptual recognition of transport SEA. SEA could influence and integrate with transport planning and transport policy development processes if planners and decision-makers changed their ways of thinking. This study also found that a tiered and integrated transport SEA, embedded in the main transport planning process at different strategic levels, has great potential to embody the environmental and sustainable concerns in transport planning and decision-making. This finding is based on several contentions supported by the recent SEA studies showing that it should not be detached from the main planning process. SEA needs to be flexible in order to meet various policies, plans and programmes (PPP) demands, and it must be value-driven, not impact-oriented. A tiered, integrated transport SEA provides ways to overcome identified transport SEA application impediments. This two-in-one planning system is a simple solution which allows transport SEA to be conducted without involving complex legal processes. It improves institutional coordination and integrates not only with planning processes but also with values and resources.