1、Designation: E3028 16Standard Practice forComputing Wheelchair Pathway Roughness Index asRelated to Comfort, Passability, and Whole Body Vibrationsfrom Longitudinal Profile Measurements1This standard is issued under the fixed designation E3028; the number immediately following the designation indica
2、tes the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the mathematical proces
3、sing oflongitudinal profile measurements to produce a wheelchairpathway roughness statistic called the Wheelchair PathwayRoughness Index (WPRI).1.2 This provides a standard practice for computing andreporting an estimate of pathway roughness for sidewalks andother pedestrian surfaces.1.3 The values
4、stated in SI units are to be regarded as thestandard. The inch-pound units given in parentheses are forinformation only.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-pr
5、iate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E867 Terminology Relating to Vehicle-Pavement SystemsE1364 Test Method for Measuring Road Roughness byStatic Level MethodE1926 Practice for Computing In
6、ternational Roughness In-dex of Roads from Longitudinal Profile MeasurementsE1927 Guide for Conducting Subjective Pavement RideQuality RatingsE2133 Test Method for Using a Rolling Inclinometer toMeasure Longitudinal and Transverse Profiles of a Trav-eled Surface3. Terminology3.1 Definitions:3.1.1 lo
7、ngitudinal profile measurement, na series of eleva-tion values taken at a constant interval along a wheel track.3.1.1.1 DiscussionElevation measurements may be takenstatically, as with rod and level per Test Method E1364 ordynamically using a rolling inclinometer per Test MethodE2133.3.1.2 traveled
8、surface roughnessthe deviations of a sur-face from a true planar surface with characteristics dimensionsthat affect vehicle dynamics, ride quality, dynamic loads, anddrainage, for example, longitudinal profile, transverse profile,and cross slope.3.1.3 wave number, nthe inverse of wavelength.3.1.3.1
9、DiscussionWave number, sometimes called spatialfrequency, typically has units of cycle/m or cycle/ft.3.2 Definitions of Terms Specific to This Standard:3.2.1 Wheelchair Pathway Roughness Index (WPRI), nanindex computed from a longitudinal profile measurement usinga standard 70 mm (2.5 in.) diameter
10、wheel with no deformationand no affects from speed. The index represents the totalvertical deflection of that wheel as it travels over a surface.3.2.1.1 DiscussionWPRI is reported in either millimetersper meter (mm/m) or inches per foot (in./ft).3.2.2 Mean Wheelchair Pathway Roughness Index(MWPRI),
11、nthe average of the WPRI values for multipletrials expressed in millimeters per meter or inches per foot.3.2.3 True Wheelchair Pathway Roughness Index, nthevalue of WPRI computed for a longitudinal profile measure-ment with the constant interval approaching zero.3.2.4 wheel path, na line or path fol
12、lowed by a non-deformable tire of a wheeled vehicle on a traveled surface as itapproaches zero speed.4. Summary of Practice4.1 This practice was developed specifically for estimatingwheelchair pathway roughness from longitudinal profile mea-surements.4.2 Longitudinal profile measurements for one whe
13、el trackare transformed mathematically by a computer program and1This practice is under the jurisdiction of ASTM Committee E17 on Vehicle -Pavement Systems and is the direct responsibility of Subcommittee E17.33 onMethodology for Analyzing Pavement Roughness.Current edition approved Aug. 1, 2016. Pu
14、blished August 2016. DOI: 10.1520/E3028-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM Int
15、ernational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1accumulated to obtain the WPRI. The profile shall be repre-sented as a series of elevation values measured at equallyspaced intervals along the traveled path.4.3 The WPRI scale starts at zero for a surfac
16、e with noroughness and covers positive numbers that increase in pro-portion to roughness. Fig. 1 provides WPRI value descriptorsderived from simulated and community surfaces made ofwood, segmental paving units, cast-in-place concrete, andasphalt.5. Significance and Use5.1 This practice provides a me
17、ans for obtaining a quanti-tative estimate of a surface property defined as roughness usinglongitudinal profile measuring equipment.5.1.1 The WPRI can be obtained from instruments whichcan capture high-resolution (described in X1.1.2) longitudinalprofiles. The Pathway Measurement Tool (PathMet) is t
18、he onlyknown instrument for this purpose.5.1.2 The WPRI is stable with time because true WPRI isbased on the concept of a true longitudinal profile, rather thanthe physical properties of a particular type of instrument.5.2 When profiles are measured simultaneously for multipletraveled wheel tracks,
19、the MWPRI is a better measure ofwheelchair pathway surface roughness than the WPRI foreither individual wheel track.5.3 Wheelchair pathway roughness data can be useful indetermining the vibration exposure experienced by a wheel-chair user. (See Fig. 1.)5.3.1 Vibration exposure has been linked to pai
20、n and inju-ries in wheelchair users and the WPRI of traveled surfacesprovides the ability to quantify the vibration exposure awheelchair user will experience when traveling that surface.3,45.3.2 Knowledge of the vibration exposure a wheelchairwill experience on traveled surfaces will allow steps to
21、betaken to minimize their exposure, reducing the likelihood ofpain and injury.6. Longitudinal Profile Measurement6.1 The longitudinal profile measurements can be obtainedfrom equipment that operate in a range of speeds, but the speedshall not affect the longitudinal profile data.6.2 The elevation pr
22、ofile measuring equipment used tocollect the longitudinal profile data used in this practice shallhave accuracy to measure the longitudinal profile attributes forcomputation of the WPRI in accordance with X1.2.2.7. Computation of Wheelchair Pathway Roughness Index7.1 This practice computes a WPRI fr
23、om an algorithmshown in Appendix X2.7.2 This practice presents a sample computer program forthe computation of the WPRI from the recorded longitudinalprofile measurement.7.2.1 The computer program accepts the elevation andhorizontal profile data sets as input and then calculates theWPRI values for t
24、hat profile data set.7.2.2 Alisting of the computer program for the computationof WPRI is included in this practice as Appendix X2.7.2.3 A provision has been made in the computer programlisting (Appendix X2) for the computation of WPRI fromrecorded longitudinal profile measurements in either SI orin
25、ch-pound units.7.2.4 The input to the sample WPRI computer program is anumerical profile data set stored in a 2N .xls format. In thisformat, the profile data appear as a multi-row, two columnarray with the longitudinal distance data points in Column 1and the vertical distance data points in Column 2
26、. The profiledata point interval should be in the range of 0.5 to 2.0 mm.7.2.4.1 The computer program shall round the input to 3decimal places no matter the input.3Boninger, M.L., et al., “Investigating neck pain in wheelchair users,” Am J PhysMed Rehabil, Vol. 82, No. 3, 2003, pp. 197202.4DiGiovine
27、, C.P., et al., “Whole-body vibration during manual wheelchairpropulsion with selected seat cushions and back supports,” IEEE Trans Neural SystRehabil Eng, Vol. 11, No. 3, 2003, pp. 311322.NOTE 1The MWPRI scale is identical to the WPRI scale.FIG. 1 Wheelchair Pathway Roughness Index and RatingsE3028
28、 1627.2.4.2 If the input to the WPRI computer program is ininch-pound units, alternative code has been provided to convertthe data to millimeters with the least significant digit beingequal to the least significant digit provided by the input or 0.1mm.7.3 The distance interval over which the WPRI is
29、 computedis discretionary, but shall be reported along with the WPRIresults.An interval of 16 ft (4.87 m) has been used successfullyin the past and has been shown to be repeatable.7.4 Validation of the WPRI program shall be completedwhen it is installed. Provision for the WPRI program installa-tion
30、validation is in this practice.7.4.1 The sample profile data set SAMPLE DATA.XLS hasbeen provided in SI units in Appendix X2 for validation of thecomputer program installation.7.4.2 Using the sample profile data set SAMPLEDATA.XLS in Appendix X2 as input to the WPRI computerprogram, a WPRI value of
31、72.64 mm should be computed.8. Report8.1 Include the following information in the report for thispractice:8.1.1 Profile Measuring DeviceThe name, serial number,manufacturer, and class of the profile measuring device used tomake the profile measurement per Test Method E1364 and TestMethod E2133.8.1.2
32、 Longitudinal Profile MeasurementsData from theprofile measuring process shall include the date and time of dayof the measurement, the location of the measurement (latitude/longitude coordinates), length of measurement, and the de-scriptions of the surface being measured.8.1.3 WPRI ResolutionIf unit
33、s reported are mm/m, thenthe WPRI shall be reported to the nearest one tenth of a mm/m.If the reported units are in./ft, then report the WPRI to thenearest hundredth of an in./ft.8.1.4 Profile SegmentIf a continuous profile contains sec-tions that cannot be measured using the profile measuringdevice
34、, the report shall note the location, length, and include adescription of each discontinuity.9. Precision and Bias9.1 The precision and bias of the computed WPRI is limitedby the procedures used in making the longitudinal profilemeasurement.9.2 For the effects of the precision and bias of the measur
35、edprofile on the computed WPRI, see precision and bias inAppendix X1.10. Keywords10.1 longitudinal profile; pathway; pedestrian; roughness;sidewalk; wheelchair; Wheelchair Pathway Roughness IndexAPPENDIXES(Nonmandatory Information)X1. PRECISION AND BIASX1.1 PrecisionX1.1.1 The precision of the compu
36、ted WPRI is limited bythe procedures used in making the longitudinal profile mea-surementX1.1.2 WPRI precision depends on the interval betweenadjacent profile elevation measures. Reducing the intervaltypically improves the precision. An interval in accordancewith X1.2.2 is recommended. For some surf
37、ace types, a shorterinterval will improve precision. More information about thesensitivity of WPRI to the profile data interval is beingdeveloped.X1.1.3 WPRI precision is limited by the degree to which atraveled path on the pedestrian pathway can be profiled. Errorsin locating the traveled path long
38、itudinally and laterally caninfluence the WPRI values, because the WPRI will be com-puted for the profile of the traveled path as measured, ratherthan the travel path as intended. These errors are reduced byusing longer profiles.X1.1.4 If measurements are taken so that the least signifi-cant digit i
39、s 0.1 mm or smaller, computational errors due torounding can be safely ignored.X1.2 BiasX1.2.1 The bias of the computed WPRI is typically limitedby the procedures used in making the longitudinal profilemeasurement.X1.2.2 WPRI bias depends on the interval between adjacentprofile elevation measures. A
40、n interval of between 0.5 and 2.0mm is necessary. Shorter intervals improve precision but havelittle effect on bias. More information about the sensitivity ofWPRI to the profile data interval is being determined.X1.2.3 Many forms of measurement error cause an upwardbias in WPRI due to variations in
41、profile elevation frommeasurement error not correlated with the profile changes.Some common sources of positive WPRI bias are: height-sensor round-off, mechanical vibrations in the instrument thatare not corrected, and electronic noise. Bias is reduced by usingprofiler instruments that minimize thes
42、e errors.E3028 163X2. WHEELCHAIR PATHWAY ROUGHNESS INDEX COMPUTER PROGRAMX2.1 Included in this appendix is the coding in Matlablanguage for a computer program (see Fig. X2.1) whichcalculates the Wheelchair Pathway Roughness Index as pre-scribed by this practice. The .xls file standard_data.xls shoul
43、dhave columns 1 and 2 filled with data; Column 1 withlongitudinal distance and Column 2 with vertical distance.X2.2 The sample program can process data files containingtwo columns of data: one for the longitudinal distance and onefor the vertical distance. For SI data, the program assumes theinput a
44、mplitudes are stored in millimeter units; if inch-pound,inches for vertical and feet for horizontal.X2.3 The sample data file shown in Table X2.1 is in SI units(mm) and contains 400 profile data point pairs. The recordinginterval for the data was 1.0 mm. The WPRI calculated shouldbe 72.64 mm/m.FIG.
45、X2.1 Sample Matlab Program to Compute Wheelchair Pathway Roughness IndexE3028 164FIG. X2.1 Sample Matlab Program to Compute Wheelchair Pathway Roughness Index (continued)E3028 165FIG. X2.1 Sample Matlab Program to Compute Wheelchair Pathway Roughness Index (continued)E3028 166FIG. X2.1 Sample Matlab
46、 Program to Compute Wheelchair Pathway Roughness Index (continued)E3028 167TABLE X2.1 Sample Profile Data from STANDARD DATA.XLS for Longitudinal (Lon) measurements recorded with an encoder andVertical (Vert) measurements recorded with a laser (mm)Lon Vert Lon(cont)Vert(cont)Lon(cont)Vert(cont)Lon(c
47、ont)Vert(cont)Lon(cont)Vert(cont)0.0 130.3 40.0 130.1 80.0 134.9 120.0 131.8 160.0 130.61.0 130.3 41.0 130.1 81.0 135.5 121.0 131.5 161.0 130.52.0 130.3 42.0 130.1 82.0 136.1 122.0 131.3 162.0 130.43.0 130.3 43.0 130.1 83.0 136.7 123.0 131.1 163.0 130.44.0 130.3 44.0 130.2 84.0 137.5 124.0 131.0 164
48、.0 130.45.0 130.3 45.0 130.2 85.0 138.3 125.0 131.0 165.0 130.56.0 130.3 46.0 130.2 86.0 138.9 126.0 130.9 166.0 130.67.0 130.3 47.0 130.2 87.0 139.5 127.0 130.9 167.0 130.68.0 130.3 48.0 130.2 88.0 140.3 128.0 130.9 168.0 130.79.0 130.3 49.0 130.2 89.0 141.0 129.0 130.9 169.0 130.610.0 130.4 50.0 1
49、30.2 90.0 141.7 130.0 130.9 170.0 130.611.0 130.4 51.0 130.2 91.0 142.2 131.0 130.8 171.0 130.312.0 130.4 52.0 130.2 92.0 142.5 132.0 130.8 172.0 130.313.0 130.3 53.0 130.2 93.0 142.7 133.0 130.7 173.0 130.314.0 130.3 54.0 130.2 94.0 142.8 134.0 130.6 174.0 130.315.0 130.2 55.0 130.3 95.0 142.7 135.0 130.5 175.0 130.316.0 130.1 56.0 130.3 96.0 142.5 136.0 130.5 176.0 130.317.0 130.1 57.0 130.3 97.0 142.4 137.0 130.5 177.0 130.318.0 130.1 58.0 130.3 98.0 142.2 138.0 130.5 178.0 130.319.0 130.1 59.0 130.2 99.0 142.1 139.0 130.5 179.0 130.320.0 130.1 60.0 130
