The National Academies Press

Currently Skimming:

Pages 19-40

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.

From page 19... ... NCHRP 3-78b: Final Project Report April 2016 3 METHODOLOGY This chapter summarizes the study methodology for the project. The discussion includes the field study protocols of the various components of the Accessibility Audit, and a discussion of site selection and prioritization of research needs that guided the experimental plan. Read the entire page →
From page 20... ... NCHRP 3-78b: Final Project Report April 2016 5. Site geometry audit: The team inventoried the geometric attributes of the various study locations and compiled a photo log diary of site conditions. Read the entire page →
From page 21... ... NCHRP 3-78b: Final Project Report April 2016 3.1.2 Wayfinding and Alignment Study Protocol To determine if a crossing is usable by individuals who are blind or visually impaired, it is important to evaluate all the accessibility challenges, not just the determining-when-to-cross problem. Once the sites were selected for the indicator studies, the team selected a subset of these sites for the wayfinding studies. Read the entire page →
From page 22... ... NCHRP 3-78b: Final Project Report April 2016 The protocol is consistent with the evaluation protocol used in HRT-10-043 (FHWA 2010) and with many state laws on driver yielding ("in" vs. Read the entire page →
From page 23... ... NCHRP 3-78b: Final Project Report April 2016 • Treatment cost, with a higher priority for treatments with low capital cost; • Likelihood of success, with a higher priority to treatments that are likely to have a high benefit to accessibility; and • Boundary conditions, with a higher priority to treatments and sites that are expected to provide better insights on the boundary conditions between accessible and non-accessible. When weighing studies in support of different models the team considered the following items: • Expected impact, with a higher priority to models that are expected to have a key impact on accessibility (e.g. Read the entire page →
From page 24... ... NCHRP 3-78b: Final Project Report April 2016 Table 3-1: CTL Sites ID Type St1 St.2 City State No. Lanes Treatment Studied Before Prior Project 1 CTL N Wilmot Rd E Read the entire page →
From page 25... ... NCHRP 3-78b: Final Project Report April 2016 Table 3-2: Multi-Lane RBT Sites ID Type St1 St.2 City State No. Lanes Treatment Studied Before Prior Project 25 Multi-RBT Golden Rd Johnson Golden CO 2 PHB 1, RCW 1 Yes n/a 26 Multi-RBT Golden Rd Ford Golden CO 2 RCW 1 No n/a 27 Multi-RBT E Orange Ave Jim Lee Rd Tallahassee FL 2 Offset CW No NIH 28 Multi-RBT N 40th St E Hanna Ave Tampa FL 2 Low-Speed No n/a 29 Multi-RBT N 40th St E Yukon St Tampa FL 2 Low-Speed No n/a 30 Mulit-RBT MLK Jr Blvd N Central Ave Kissimmee FL 2 Entry Speed Humps Yes NIH 31 Multi-RBT Causeway Blvd Mandalay Clearwater FL 2 Signal, Offset CW No n/a 32 Multi-RBT Clay Terrace Blvd Carmel IN 2 RRFB Yes FHWA 33 Multi-RBT Maple Rd Drake Rd West Bloomfield MI 2/3 PHB Yes NIH 34 Multi-RBT Maple Rd Farmington Rd West Bloomfield MI 2/3 RRFB Yes NIH 35 Multi-RBT Jetton St Griffith St Davidson NC 2 RRFB* Read the entire page →
From page 26... ... NCHRP 3-78b: Final Project Report April 2016 Table 3-3: Single-Lane RBT Sites ID Type St1 St.2 City State No. Lanes Treatment Studied Before Prior Study 47 Single RBT Golden Rd Ulysess Rd Golden CO 1 n/a Yes 3-78a 48 Single RBT Gulf Dr S Bridge St Bradenton Beach FL 1 n/a No n/a 49 Single RBT W Read the entire page →
From page 27... ... NCHRP 3-78b: Final Project Report April 2016 3.2.2 Overview of Studied Channelized Turn Lane Sites Through the process of identifying research needs for CTLs, combined with an inventory of CTL treatments across the U.S., the team conducted two clustered studies of CTL accessibility in two locations across the US, supplemented by two additional isolated locations. The motivation for the clustered approach is two-fold: (1) Read the entire page →
From page 28... ... NCHRP 3-78b: Final Project Report April 2016 featured different geometric and treatment combinations, as described below with aerial views of all four locations. Read the entire page →
From page 29... ... NCHRP 3-78b: Final Project Report April 2016 Figure 3-2: CTL at Sabino Canyon Road at Tanque Verde Road, Tucson, AZ Figure 3-3: CTLs at Oracle Road and Grant Road, Tucson, AZ 29 Read the entire page →
From page 30... ... NCHRP 3-78b: Final Project Report April 2016 3.2.2.2 Boulder, CO In July 2014, the team completed data collection at six CTL locations in Boulder, CO. The study focused on three CTLs in an urban environment within the Boulder City Limits, as well as three CTLs under county jurisdiction. Read the entire page →
From page 31... ... NCHRP 3-78b: Final Project Report April 2016 Figure 3-5: CTL at 28th Street and Canyon Boulevard, Boulder, CO Figure 3-6: CTL at Foothills Parkway and Arapahoe Avenue, Boulder, CO 31 Read the entire page →
From page 32... ... NCHRP 3-78b: Final Project Report April 2016 Figure 3-7: CTL at Foothills Parkway and Baseline Road, Boulder, CO 3.2.2.3 Greenbelt, MD and Cary, NC In September 2014, the team completed data collection at a channelized turn lane in Greenbelt, MD. In November 2014, the team collected data at a CTL in Cary, NC. Read the entire page →
From page 33... ... NCHRP 3-78b: Final Project Report April 2016 Figure 3-9: CTL at Kildaire Farm Road and Tryon Road, Cary, NC 3.2.3 Overview of Studied Roundabout Sites The team collected data at a total of eight roundabout approaches at five roundabouts in four different states. The emphasis in the roundabout data collection was on the evaluation of treatments not previously evaluated in sufficient detail. Read the entire page →
From page 34... ... NCHRP 3-78b: Final Project Report April 2016 location, while the east approach showed an offset or "zig-zag" configuration. Both approaches had in-road yield to pedestrian signs installed. Read the entire page →
From page 35... ... NCHRP 3-78b: Final Project Report April 2016 Figure 3-11: Roundabout at Maple Road at Farmington Road, Oakland County, MI 3.2.3.3 Greenbelt, MD In September 2014, the team completed data collection at a roundabout with raised crosswalks. The roundabout was located at Cherrywood Lane at Metro Access Parkway, and it featured slip lanes and raised crosswalks. Read the entire page →
From page 36... ... NCHRP 3-78b: Final Project Report April 2016 Figure 3-12: Roundabout at Cherrywood Lane at Metro Access Parkway, Greenbelt, MD 3.2.3.4 Ann Arbor, MI The team studied two roundabouts in Ann Arbor, MI in October 2014. The study focused on one single- lane and one two-lane roundabout, and both featured similar treatments. Read the entire page →
From page 37... ... NCHRP 3-78b: Final Project Report April 2016 Figure 3-13: Single-Lane Roundabout in Ann Arbor, MI with Milled Rumble Strips Figure 3-14: Two-Lane Roundabout with Milled Rumble Strips in Ann Arbor, MI 3.2.3.5 Cary, NC The team collected data at a single-lane roundabout in Cary, NC in November 2014. The site at the 37 Read the entire page →
From page 38... ... NCHRP 3-78b: Final Project Report April 2016 intersection of Old Apex Road and West Chatham Street is a single-lane location with three approach legs. The team studied the west approach on Old Apex Road. Read the entire page →
From page 39... ... NCHRP 3-78b: Final Project Report April 2016 Table 3-6: Modeling Needs and Site Selection # Model Type Facility Type # of Existing Sites # of New Sites Data Source 1a Safety and Risk Prediction Model CTL 3 12 Indicator Study 1b Safety and Risk Prediction Model Single RBT 3 2 Indicator Study 1c Safety and Risk Prediction Model Multi RBT 10 6 Indicator Study 2a Yield Model CTL 3 12 Yielding Study 2b Yield Model Single RBT 3 2 Yielding Study 3a Free-Flow Speed Prediction Model CTL 3 12 Free-Flow Speed Study 3b Free-Flow Speed Prediction Model Single RBT 3 2 Free-Flow Speed Study 3c Free-Flow Speed Prediction Model Multi RBT 10 6 Free-Flow Speed Study 4 Wayfinding Assessment All 16 20 Wayfinding Study and Geometry Audit 5 Crossing Alignment Tool All 16 20 Wayfinding Study and Geometry Audit 6a Gap Utilization Model CTL 3 12 Indicator Study 6b Gap Utilization Model Single RBT 3 2 Indicator Study 6c Gap Utilization Model Multi RBT 10 6 Indicator Study 7a Yield Utilization Model CTL 3 12 Indicator Study 7b Yield Utilization Model Single RBT 3 2 Indicator Study 7c Yield Utilization Model Multi RBT 10 6 Indicator Study 3.4 IRB Approval The team requested and obtained approval for all studies necessary from the Institutional Review Board (IRB) of North Carolina State University and of the National Academy of Sciences. Read the entire page →
From page 40... ... NCHRP 3-78b: Final Project Report April 2016 This page intentionally left blank 40 Read the entire page →

From page 19...

... NCHRP 3-78b: Final Project Report April 2016 3 METHODOLOGY This chapter summarizes the study methodology for the project. The discussion includes the field study protocols of the various components of the Accessibility Audit, and a discussion of site selection and prioritization of research needs that guided the experimental plan.