Mark Johnson, PE will be giving three presentations at the 2018 TRB Annual Meeting in Washington, DC.
Jan. 9, 10:15am – 3:15pm – Roundabout Video Theater
1) Morning session: Video presentation – “Roundabout Design & Traffic Planning for All Modes”
2) Afternoon session: Case Study presentation – “Innovative Pedestrian/Bike Design Treatments in an Urban Compact Roundabout”
Jan. 9, 3:45pm – 5:30pm – Podium Presentation
3) Mark will present his paper, “The Impact of Geometric Factors on the Capacity of Single-Lane Roundabouts,” which was accepted for publication.
Co-authored with Ting-Li Lin, Ph.D., the paper compared two methods of capacity estimation – HCM gap acceptance and Kimber/Hollis’ geometric model. Our statistical analysis indicated that the geometric capacity model was more accurate. The uncalibrated geometric capacity model produced better predictions than the calibrated HCM6 model. This paper concluded that the accuracy of capacity prediction is improved by including geometric variation, and the geometric differences between roundabout sites were the primary cause of the differences in driver behavior at those sites.