Making Context Sensitive Design an Everyday Part Of Geometric Design Practice

At the last TAC meeting in 2006 in Charlottetown, a full morning was devoted to a workshop on Context Sensitive Design (CSD) practices. Nearly 100 people participated in the workshop. Four presentations were made on different aspects of CSD by Messrs. John Robinson, Tim Neuman, Roy Biller and Leonard Ng. Each presentation was followed by informed comments and suggestions from the participants. The focus was on moving CSD into mainline practise. This paper, presented by the Chair of the Workshop, is a synopsis of the main points raised in the workshop session. The overall message was one of acceptance of CSD and the need to advance the science by taking certain explicit initiatives and including the subject of CSD in the TAC Geometric Guide. In his presentation, John Robinson stressed the need for designers to dwell on the possible and never to refrain from action because it’s not “in the book.” He appealed for: • a greater use of heuristics and better understanding amongst practitioners about the derivation of design elements and parameters; • increasing design flexibility by understanding speed management and for practitioners to know more about the way geometric elements limit speeds; • more use of risk management for designers to recognize the risks inherent in their designs and how these can be evaluated. Tim Neuman gave a good background on USA applications of CSD. He pointed out that CSD must equally address safety, mobility, scenic values, history and the environment. Key to successful development is: • understanding the problem; • communicating decisions; and • showing technical leadership in making trade-offs. He stressed the need for roads to convey traffic and asked, ‘who advocates mobility?’ Roy Biller spoke on corridor applications of CSD and focused on designing to meet historical, social and political goals. He suggested treating sight distance separately from operating speeds. He also stressed the need for better articulation of values in the value engineering process. Finally, Leonard Ng spoke about CSD in suburban communities. He stressed the design need for: • respecting historical context; • a better understanding of visual clues in the roadside environment so as to moderate driver expectations; and • for creativity in deriving solutions to meet the objectives of both the community and the owner. The paper expands on the issues raised during the workshop and relates them to Human Factors. It proposes a new chapter or supplement to the TAC Geometric Design Guidelines.