## 4 Results
### Industry-Level: Market Development and Leadership  
In the **Australian** cases, a small team within TfNSW had been working for several years with the sustainability design guidelines to purposefully drive development in the infrastructure industry. By updating the SDGs, the client allowed suppliers to incrementally adjust to new requirements. The client design manager described this as an interactive learning process: _\"We're just getting better at capturing what the industry can do... and making it a case of what the industry should do.\"_ The guidelines were initially based on prescriptive requirements to provide guidance on sustainable design solutions to the still inexperienced industry. The SDGs have gradually become more open, and the fourth version is mainly based on performance requirements, with the previous prescriptive requirements included as options to meet them. In parallel, the IS Rating Scheme was developed by the Infrastructure Sustainability Council of Australia (ISCA). Both ISCA and Green Star (for buildings) started out as voluntary ratings but have now become more or less standard. ISCA includes requirements for carbon reduction in relation to a baseline and a tool to develop the baseline. To drive industry learning, ISCA mandates engagement in knowledge sharing (both good and bad experiences). Sustainability, therefore, has become regarded as part of normal design, and suppliers have pushed the development of new technology forward to gain a better position when competing for future projects. In the **Netherlands**, various collaborative agreements and strategies on how to reduce the use of fossil fuels have been developed by various actors (state, industry, NGOs, etc.) to meet national ambitions. One example is the Dutch Climate Coalition, which is specifically targeting public procurement in the infrastructure sector, including goals for carbon emission reduction. Another example is a \"deal\", DGW 2.0, which involved a wide range of infrastructure construction clients and suppliers. Two tools have played a central role in the development of procurement requirements for carbon emission reduction and sustainability, more generally, in the Dutch construction sector: the CO\({}_{2}\) Performance Ladder and DuboCalc. The CO\({}_{2}\) Performance Ladder is a certification system for company-level carbon work, while the DuboCalc tool focuses on the environmental performance of construction projects, including carbon footprints. Both are used to enable tender discounts based on carbon performance and are supported by certification and auditing bodies. The CO\({}_{2}\) Performance Ladder, especially, has widely raised carbon awareness in the industry, but since all large contractors are now certified at the highest level, the system no longer discriminates between tenders. The DuboCalc tool is particularly used for large projects with private financing and in combination with a competitive dialogue process. In the **Swedish** case, the government had launched an initiative called Fossil Free Sweden (2018) in preparation for the Paris agreement. This initiative gathered stakeholders in developing sector-specific roadmaps for carbon emission neutrality, and construction was one of these sectors. The Swedish Transport Administration (STA) is the main infrastructure client. By connecting their reduction requirement levels to the general national reduction goals, the STA aimed to communicate to the industry that they were serious about climate reduction and to provide predictability regarding future directions. The STA has further developed materials, such as tutorials for the Klimatkalkyl tool, and hosted industry conferences to disseminate knowledge and information. However, there was some criticism from the industry that the Klimatkalkyl tool does not reflect current construction practice, and interviewees emphasized that continuous dialogue between the industry and client was needed to keep it up to date.