Markides is experienced in the planning, design and management of major development projects, urban extensions and town centre regeneration schemes. He has also been involved in the design and supervision of infrastructure works. His specialist traffic expertise includes traffic impact studies for new development proposals, highway design, development of transport strategies and expert witness at planning inquiries. He set up Markides Associates in October 2016, which employs more than 30 transport planners and engineers. He was president of the Chartered Institution of Highways and Transportation in 2017-18 and is currently a trustee. He is a founding member of the Academy of Urbanism. In 2014 he acted as planning commissioner for Cyprus.