Background and Summary of a Guide for Roundabouts (2023) / Chapter Skim
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39 Appendix B: Truck and Bicycle Research CONTENTS DESIGNING FOR TRUCKS RESEARCH ..................................................................................
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40 DESIGNING FOR TRUCKS RESEARCH This summarizes truck research conducted as part of NCHRP Project 03-130. The objective was to assess roundabout design decisions for serving large trucks at multilane roundabouts.
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41 STATE OF THE PRACTICE REVIEW This summarizes the team's review of select agency guidance for multilane roundabout design for accommodating trucks entering, circulating, and exiting multilane roundabouts -- specifically concerning the use of truck cases described above and further defined in the next section. The focus is large combination tractor-trailer trucks (e.g., WB-62/WB-67)
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42 Agencies have different multilane design guidance and various documentation to support their approaches. The agency reviews are presented in reverse chronological order based on the most recent date of published guidance reviewed.
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43 Compounding the varying definitions and guidance about case type is the issue of user expectations. There is no uniformly defined approach to convey to drivers which truck case is provided and for which vehicles the design intent applies.
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44 State Document Name (Year Published) Guidance Wisconsin Department of Transportation (WisDOT)
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45 TRUCK INDUSTRY OUTREACH This section summarizes the trucking industry outreach. Outreach Approach The project team conducted outreach to trucking industry organizations nationally and at the local level, conducting interviews with five stakeholders within those organizations.
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46 DRIVER BEHAVIOR VIDEO DATA COLLECTION This section documents the driver behavior video review efforts, including: ● Review existing footage of Case 2 roundabouts for their applicability to this project. ● Set up cameras to observe trucks entering and circulating in Case 3 roundabouts at four sites.
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47 Table 2: Observation Site Footage Details Intersection City, State Intersection Configuration Date(s) Adjacent Traffic Present1 Number of Observations Case 2 Sites: Existing Footage Riverside/Northern Cross Fort Worth, TX 2x2 3/31/2015 Yes 20 No 6 County Road MM/County Road M Oregon, WI 2x1 10/24/2016 Yes 1 No 2 N Towne Road/County Highway V Deforest, WI 2x1 10/14/2016 Yes 8 No 48 I-94 EB Ramp/County Highway N Cottage Grove, WI 2x1 10/3/2016, 10/4/2016, 10/19/2016 Yes 6 No 11 US 51 NB Ramp/County Highway V Deforest, WI 2x2 10/20/2016 Yes 2 No 19 US 51 SB Ramp/County Highway V Deforest, WI 2x1 10/13/2016 Yes 2 No 3 Case 3 Sites: New Footage State Route 89 / Road 4S State Route 89 / Perkinsville Road Chino Valley, AZ 2x1 10/20/2020 Yes 40 No 38 State Route 260 / Industrial Drive Chino Valley, AZ 2x1 10/21/2020 Yes 54 No 22 State Route 89 / Road 4S State Route 89 / Perkinsville Road Camp Verde, AZ 2x1 10/21/2020 Yes 8 No 24 State Route 260 / Industrial Drive Camp Verde, AZ 2x1 10/22/2020 Yes 38 No 87 1: This variable identifies whether other vehicular traffic is present on the approach with approximately one truck length in front of or behind the truck.
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48 Case 2 Summary and Findings The Case 2 videos include 128 observations from 6 locations. Of these, 39 observations include the presence of adjacent traffic (i.e., other vehicles in front of, behind, or alongside a truck close enough to reasonably affect the truck driver's behavior)
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49 Lane Discipline by Movement Truck driver behavior analyzed for left-turning and through movements was similar to the trends described in the aggregated findings above, with half or more of truck drivers maintaining lane discipline on approach (50 percent for left turns and 63 percent for through movements) and marginal sensitivity to adjacent traffic.
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50 Truck Apron Use The 311 observations included 8 drivers who used the truck apron: 4 through truck drivers in the left lane, 3 left-turning truck drivers, and 1 U-turning driver. Of the 11 truck drivers using the left lane, 6 used the truck apron.
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51 16% higher in the presence of adjacent traffic than without it. For Case 3 sites, the majority of observed encroachments were minor and would not have precluded an adjacent passenger vehicle.
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52 STATE OF THE PRACTICE REVIEW The state of the practice review included material related to designing for bicycles at roundabouts, including design guidance, agency practices, and information from a virtual field review. The review focused on identifying design guidance and practices: ● A review of publications released since 2010 related to bicycle facility design.
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53 Design Principles The publication review helped identify the following synthesized list of principles related to designing for people biking, specifically people "interested but concerned" in biking. ● Minimize exposure to conflicts.
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54 The literature review identified many examples of bicycle design treatments that met multiple draft design principles. However, by reviewing design treatments against the list of draft design principles, the list of design principles was modified to remove and combine principles deemed too similar or not applicable.
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55 ● Reduce speeds at conflict points, including between people biking and walking. ● Separate modes, including the need to provide a "raised element" between modes that is detectable underfoot and the preference for separated facilities when bike or pedestrian volumes are high enough to regularly require people walking and biking to share the same space.
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56 ○ Transitions between pedestrian, bicycle, buffer zones, and crossings must be clearly identifiable (B)
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57 ○ Median islands should have a width of at least 6 ft. ○ Detectable warning surfaces should be included on the pedestrian crosswalk to alert pedestrians with visual impairments of the transition into a safe space to wait.
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58 (Kittelson & Associates 2010)
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59 Figure 2: N Terry St, Roosevelt Blvd, Fern Ridge Path -- Eugene, OR Design Principle Adherence Minimize exposure to conflicts. The westbound bike lane approach does not provide taper length for neck down and does not include a dashed lane to encourage merging.
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60 Figure 3: SW Reed Market Road/N Alderwood Circle/Deschutes River Trail -- Bend, OR Design Principle Adherence Minimize exposure to conflicts.
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61 Figure 4: Pleasant Hill Road/Olympic Blvd/Olympic Oaks Drive -- Lafayette, CA Design Principle Adherence Minimize exposure to conflicts. Channelized right-turn lane might not be necessary.
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62 Figure 5: W Quad and Shields Avenue -- Davis, CA Design Principle Adherence Minimize exposure to conflicts.
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63 Figure 6: Napa, California (City of Napa)
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64 Figure 7: W Vine Drive/N Shields Street -- Fort Collins, CO Design Principle Adherence Minimize exposure to conflicts.
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65 Figure 8: W Main St/Spring Mill Road -- Carmel, IN Design Principle Adherence Minimize exposure to conflicts.
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66 Figure 9: Worcester Union Station (Front Street/Summer Street/Shrewsbury Street/Grafton Street) -- Worcester, MA Design Principle Adherence Minimize exposure to conflicts.
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67 Figure 10: Waterloo Road/A3200 York Road/Stamford Street -- London, UK Design Principle Adherence Minimize exposure to conflicts. The roundabout is signalized, which separates some of the merging movements (for instance, bus/bike lane entering in southeast corner has its own signal to enter)
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68 Figure 11: A1036/Moor Lane -- York, UK Design Principle Adherence Minimize exposure to conflicts.
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69 Figure 12: Rembrandtweg/Saskia van Uylenburgweg/Eleanor Rooseveltlaan -- Amstelveen, Netherlands Design Principle Adherence Minimize exposure to conflicts.
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70 TREATMENT CONCEPTS The project team developed treatment concepts to demonstrate the latest bicycle facility and pedestrian design techniques for various roundabout scenarios. The treatment concepts are the basis for figures in the Guide.
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71 REFERENCES American Association of State Highway and Transportation Officials.
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72 National Association of City Transportation Officials (NACTO)
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