Context Sensitive Design to Influence Operating Speeds

Focus Area

Context Sensitive Solutions


Community & Cultural Concerns, Environmental Process






2-3 years

Research Idea Scope

Inappropriate speed is one of the primary safety hazards facing highway users.
Most road agencies attempt to achieve the right operating speed among drivers by imposing speed limits. Unfortunately several national and international studies have shown that the speed limit is very much violated, and at best serves only as a guide to drivers. The ability to influence vehicle speeds through the selection of the characteristics of the roadway and of the adjacent environment could be a boost to improving safety on our roadways. For several years now, this specific topic of investigation has also been identified as a very high priority research need by the Transportation Research Board (TRB) AFB50T (joint committee) Context Sensitive Design & Solutions Task Force; by TRB’s AFB40 Landscape and Environmental Design Committee; and in TRB sponsored CSS Research Needs Workshops that attract a broad range of disciplines and stakeholder perspectives in transportation.     
It is a compelling transportation challenge and public interest to reinforce and achieve improved and more desirable driver and interrelated modal behaviors, safety, and performance along our nation’s roadways and in a “substantive” and context sensitive manner. Greater predictability, success, and cost-effectiveness will require a more comprehensive understanding of the contextual circumstances and the specific combinations of roadway and roadside attributes that can contribute to improved and “substantive” (actual) driver and interrelated modal behaviors and safety performance through a better informed approach to our considerations and applications of flexibility in transportation planning and design.
Contrary to conventional assumptions and approaches that seek to advance roadway safety, there is a limited and less-known, but growing, body of international research and project case studies that correlate roadway and roadside attributes, combinations, and variables with less-understood improvements in driver and interrelated modal behaviors, safety, and performance … along with many other social, environmental and economic benefits associated with CSS. Unfortunately, many of the contemporary investigators, who have contributed to this limited, less-known, and less-understood body of research, will tell you that this area of inquiry has not been emphasized, supported, or funded adequately to date. Consequently, the follow-up research has not been advanced or pursued widely or rigorously enough to address the gaps and limitations or inadequacies revealed through previous investigations. To adequately inform flexibility in transportation planning, design, and decision-making in this regard, additional research methodologies and data are needed to definitively correlate specific contextual circumstances and combinations of roadway and roadside attributes with CSS and “substantively” improved safety performance.
RESEARCH OBJECTIVEThe objective of this research is to determine the interaction of the design elements and the context-related elements that influence drivers’ perceptions of appropriate operating speeds, establish the dimension and complexity of these influences and, ultimately, design harmonised “roadscapes”, in terms of new realisations but also in regards to strategic (re)qualification projects. The research, therefore, aims to investigate driver behavior in different roadway, road-side and environmental contexts in order to have a better understanding of the interaction of design elements and drivers’ perceptions and responses. After a monitoring study (Work Package1) experiments will be carried out by means of virtual reality scenarios images (WP2) and driving simulator experiments (WP3 and WP4). Virtual scenarios images will be used in order to investigate drivers’ roadway-environment comprehension and the consequent perceptions of risk, which rate discomfort of the different scenarios. Driving simulator experiments will be used in order to investigate drivers’ speed behavior in different scenarios corresponding to the road environment of existing infrastructures and to a selected gamma of different design options. Finally, selected design features will be implemented and monitored in real world (WP5) and the out-coming Context-Sensitive Design Guidelines (C-SDG) will be edited (WP6).

Urgency and Payoff

URGENCY, PAYOFF POTENTIAL, AND IMPLEMENTATIONThe urgency and payoff potential are both high in terms of the contribution this research may make toward better-informed and more successful and cost-effective application of flexibility in decision-making and design to advance both the mainstreaming of CSS and “substantively“ based safety assumptions, guidance, and modeling to improve driver and interrelated modal behaviors, safety, and performance nationwide. Application of context sensitive combinations of roadway and roadside attributes that “substantively” improve behaviors, safety, and performance can also provide for many other social, environmental, and economic objectives and benefits for communities, stakeholders and the public. As mentioned before, in regards to the 2005 AASHTO CSS Survey of state DOTs and the TRB sponsored investigations of high priority CSS Research Needs, there clearly is considerable urgency and payoff potential for this type of research and the benefit it may provide to more broadly informed and widespread innovation in the application of flexibility in design and the mainstreaming of CSS principles nationwide.

Suggested By

RNS. Sponsoring Committee: AFB40, Landscape and Environmental Design