Sustainable design indicators: Roadway project as an example

Environmental sustainability has been more examined in the construction industry in recent years. But it is still difficult for engineering designers to incorporate sustainability into their work without practical methods. The design stage is key in the life cycle to integrating sustainability into construction projects. Assessment of sustainable design performance can be an initiative to pursue sustainability. This paper proposes the ratio of items considered/adopted and man-hour spending to measure project sustainable design performance. The two indicators were tested on six roadway projects to validate their applicability on engineering design. The results show that the ratios of items considered and adopted are from 34% to 87%, meaning the many suggested sustainability items can be incorporated into design. The man-hours spent on sustainability are from 2% to 12%, meaning sustainable design initially takes more time than conventional design. The engineering design itself does not cause environmental impact. But the proposed indicators can examine the effort devoted into sustainability in the design stage. This early step helps predict the future environmental performance of designed products.