The global markets for autonomous systems have grown significantly in recent years. In rapidly evolving markets, maintaining a leading position requires ensuring national expertise, fostering cross-border collaboration, and leveraging rapidly advancing technology. Finland currently lacks adequate testing environments where SMEs, research institutions, and cities can develop, test, and validate autonomous technologies, such as mobile robotics and swarm intelligence, before introducing them to the market or integrating them into urban infrastructure. This slows down the commercialization and adoption of innovations while limiting the competitiveness of Finnish actors in the global market. The Scale Down project addresses this need by providing a testing platform where autonomous systems can be experimented with and optimized before deployment in the market or urban infrastructure. The Scale Down project develops and pilots a modular testing environment for the development of autonomous systems and mobile robotics. This is a physical testing environment where companies and research organizations can test autonomous robotic systems and their operations in various urban scenarios. Additionally, digital elements will be developed to support the use of the physical testing environment. The project will possibly be carried out in collaboration with the Lapland parallel project 406041 Polar Autonomous & Social Robotics. In Uusimaa, the focus is on scaling urban infrastructure into a mobile robotics testing environment, while in Lapland, the emphasis is on providing a test area that covers environments such as warehouses and terminals. This collaboration enables broader knowledge exchange and supports the international scalability of companies’ innovations. The project emphasizes fleet operations, including swarm robotics and networked sensing, where autonomous mobile robots can share observational data and operate together efficiently. This enables robot coordination and optimization in applications such as urban traffic, maintenance, and logistics. The project explores and tests how autonomous systems can adapt to various urban environments and scale into broader networked solutions. The physical urban test environment being built in the project, called Sandbox, is a modular test environment where the operations of autonomous robots can be developed and tested safely. The urban test environment refers to a miniaturized model of an urban setting and its infrastructure, serving as an experimental and innovation platform for robotics applications, thus creating entirely new opportunities for development. The Sandbox includes various urban challenges that are particularly meaningful to replicate in the test environment, enhancing robots’ ability to recognize obstacles, navigate efficiently, and make decisions in dynamic situations. A precise tracking system will be integrated into the test area, utilizing LiDAR technology, RGB-D cameras, as well as ultrasonic and infrared sensors. The test platform will also be complemented with digital elements to assist in the operation of mobile robots. Artificial intelligence (AI) will play a key role in optimizing sensor fusion, combining data from various sensors, such as cameras and LiDAR systems, allowing autonomous systems to perceive their environment independently. AI will also enable networked sensing, where autonomous mobile robots share observation data with each other in real-time, forming a shared situational awareness and functioning as a swarm. The project will include pilot programs in collaboration with companies, testing and developing autonomous solutions for real-world applications. Additionally, the project will produce a workbook and an open data library, which will include mapping data from the test environment and sensor data for use by companies and research institutions. The project’s objective is to promote the safe and efficient adoption of autonomous systems in urban environments while enhancing the competitiveness and growth of SMEs. The testing environment provides a platform for developing and testing new robotics and automation solutions without requiring large initial investments. Moreover, the test environment will remain part of Metropolia and Aalto University’s research and development activities after the project, ensuring continuous development in the field of autonomous systems. The project has significant societal and economic impacts. It supports sustainable development by enabling energy-efficient and resource-wise autonomous solutions for urban environments. Additionally, it advances domestic robotics expertise and strengthens Finland’s position as a development hub for autonomous systems. The project outcomes will remain openly available, ensuring their wide accessibility even after the project ends.