Improving road safety is currently based mostly on Education, Enforcement and Engineering or the 3 Es. Despite these measures having saved millions of lives since their inception in around 1915, millions of people are still injured or killed in accidents worldwide annually. One relatively unexplored area is the use of driver's tacit (unspoken) knowledge to help in the reduction of accidents, particularly in the area of speed management. Participatory design may offer a way to help utilise drivers' tacit (hidden) knowledge for the improvement of speed management and road safety techniques in a positive and ethical manner. Involvement in the process may also aid in the improvement of drivers' behaviour and attitudes. Previous research in participatory design indicates that the benefits of participatory design are quick acceptance of new designs and innovative solutions to difficult problems, as well as a sense of ownership of the new artefact. My research has investigated the efficacy of using participatory design in road safety. This was done by having participants take part series of four different types of workshops aimed at improving driver behaviour and attitudes as well as road design using models. The research involved a total of 105 participants with group sizes ranging from 3 to 28 people. It was found that participatory design workshops were capable of: allowing people to redesign a variety of roads and improve them by reducing their estimated speeds, without adversely affecting other ratings such as safety, aesthetics, preference and liveability; improving self reported driver behaviour; and allowing the interaction of people from various backgrounds in a positive and stimulating environment. Workshops were also rated highly as a teaching and design tool by all those involved in the process. Finally, unlike standard participatory design processes, some workshops also included more than just the design team with the inclusion of additional participants as audience members. This was also found to be a practical method of including more people in the participatory design process without reducing the effectiveness of the process.