Infrastructure projects have been requested to consider sustainability in recent years. However, many engineers have little idea how to start with this new issue. It would help engineers to incorporate sustainability if the difficulties and their reasons can be identified. This research investigated the levels of difficulty for sustainable design, by taking roadways as an example. It first collected 14 roadway design work disciplines such as drainage from a large engineering consulting company. Then it reviewed literature and practice to identify 60 sustainable items, and categorized them into 14 disciplines to establish a checklist. Finally, the checklist was used to interview designers to indicate the levels of difficulty of adopting these sustainable items. The difficulties to achieve sustainability into design are classified into three levels compared with traditional work: equal, medium and high. Twenty eight of the 60 sustainable items were evaluated at the same level of difficulty as traditional design. Approximately half of the items would not increase the difficulty when incorporated into design. The average difficulty would be between equal and medium level. Compared with traditional design work, incorporating sustainability into roadway design would increase certain difficulty.