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Recently, speed management practices have shifted away from an historical focus on the 85th percentile speed toward a safe systems approach that is focused on promoting safer speeds in all roadway environments through a combination of thoughtful, equitable, context-appropriate roadway design, appropriate speed-limit setting, targeted education, outreach campaigns, and enforcement. This includes the incorporation of a Complete Streets approach to roadway design, which uses cross-sectional characteristics that reduce speeds and create a more accommodating environment for people biking and walking. This study aims to inform this design process by advancing our understanding of how drivers adjust their speeds based on changes in the posted speed limit and other contextual factors related to the roadway environment. Field data were collected from 19 highway corridors across Minnesota using handheld lidar guns to track drivers' operating speeds as they transitioned from high-speed rural highways to lower-speed rural and suburban communities. The study results in the estimation of a series of speed reduction factors (SRF), which detail the impacts of various site-specific characteristics on travel speeds. Various features are shown to serve as effective speed-control measures, such as single-lane roundabouts, which reduced speeds by about 7 mph. Speeds were also lower on segments that included two-way, left-turn lanes (0.7mph), depressed medians (1.2 mph), and raised medians (3.1 mph). The results also show that drivers typically begin reducing their speeds approximately 800 ft upstream of posted speed limit signs and continue to reduce their speeds to a distance 400 ft beyond the sign location. Ultimately, this study will allow for a more proactive and data-driven approach to highway design that considers the needs of all users.

This research sought to identify best practices for channelized right-turn lanes (CRT) that better accommodate the safety and accessibility needs of all road users. This was accomplished through a comprehensive literature review, a state-of-the-practice survey of state and local roadway agencies (nationwide and within Minnesota), a review of agency policy and guidance materials (nationwide and MnDOT), and a series of focus group meetings focused on vulnerable road users. Feedback received both from the survey of transportation agencies and the focus group sessions performed as a part of this research suggest that roadway agencies throughout the United States are moving toward proactive policies for the use of CRTs that emphasize safety and mobility for vulnerable road users. This movement is generally based on the concerns for the safety of vulnerable road users outlined in the prior section and commonly includes 1.) minimizing the use of CRTs at urban and suburban intersections and/or 2.) designing new CRT facilities or retrofitting existing facilities with mitigation strategies to improve the safety and accessibility for vulnerable road users. This information was synthesized along with the best practices found in the research literature and agency policy/guidance materials to develop implementation guidance, which is organized within the report as follows: 1.) guidance for use of CRTs based on the project scenario; 2.) traffic control recommendations for CRTs; 3.) recommended design features for CRTs; and 4.) recommended mitigation strategies intended to improve CRT safety and/or accessibility for vulnerable road users.