Measuring, Characterizing, and Reporting Pavement Roughness of Low-Speed and Urban Roads (2019) / Chapter Skim
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Pages 49-66
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49 This chapter presents the results from an experiment that was conducted to correlate objective measurements of discomfort caused by vehicle vibration to measures of road roughness on urban and low-speed roadways. The experiment included simultaneous measurements of longitudinal road profile and accelerations at interfaces between the vehicle and the driver on 29 urban and low-speed pavement sections using 3 test vehicles.
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50 Route Test Sections County Functional Class Speed Limit Range (mi/hr) Jackson Road/Huron Street 3 Washtenaw 3 35 Grand River (M-5)
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51 view that includes the profiler and the left wheel encoder. Comparison of the outputs of each alternative under different measurement conditions helped verify the calibration of the rotational encoders and the starting point of each test section.
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52 transient events (See Section 4.2.1.2.)
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53 acceleration is greater than 1.5. In such cases, SAE J2834 recommends the use of RMQ in place of RMS for quantifying discomfort.
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54 and a peak at 9.69 Hz associated with resonant motion of the unsprung mass. At a simulated travel speed of 49.7 mi/hr (80 km/hr)
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55 4.2.2.3 Ride Number RN was developed to characterize user opinion of pavement rideability from measured road profiles (Janoff et al. 1985; Janoff 1988)
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56 Figure 75. RMS weighted vertical acceleration, floor/foot interface, SUV.
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57 compared to using the left wheel path only for the SUV and the full-sized van, but not as good for the mid-sized sedan. Overall, correlation for RN was comparable to correlation for the IRI from the left wheel path.
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58 summary index (i.e., IRI and GCARSV, respectively.) Using RMS velocity in place of average rectified velocity for GCARVV improved correlation for the SUV, reduced correlation for the full-sized van, and caused mixed results for the mid-sized sedan.
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59 shifted the emphasis on longer wavelength content relative to suspension response. GCRMSAV, which reports simulated sprung mass acceleration at the travel speed from each test run, improved correlation compared to the IRI for the SUV and the full-sized van.
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60 to a 1968 Chevrolet Impala (Burchett et al.
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61 (i.e., wavy) and short-wavelength content (i.e., choppy)
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62 Figure 79. Ratio of MTV to RMS seat/buttock vertical acceleration, mid-sized sedan.
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63 Figure 82. Ratio of RMQ to RMS seat/buttock vertical acceleration, mid-sized sedan.
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64 these test sections requires reporting a measure of localized roughness in addition to the average roughness level. Figures 85–87 show the relationship between MTV at the seat/buttock interface and peak localized roughness for the left wheel path for each test vehicle.
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65 For example, Figure 88 shows the RMS weighted acceleration at the seat/buttock interface averaged over 1-second intervals for a test run on West Grand River (Section 23)
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66 Figure 88. RMS weighted acceleration, pass over West Grand River.
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