ASTM E2467-2005(2018) Standard Practice for Developing Axle Count Adjustment Factors.pdf

1、Designation: E2467 05 (Reapproved 2018)Standard Practice forDeveloping Axle Count Adjustment Factors1This standard is issued under the fixed designation E2467; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi

2、on. 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 standard practice describes techniques for adjustingobserved or assumed axle counts so that they will representcorresponding

3、 estimated vehicle counts as part of roadwaytraffic monitoring.1.2 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-priate safety, health, and environmental practices and dete

4、r-mine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendat

5、ions issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 Other:Traffic Monitoring Guide, U.S. Department ofTransportation, Federal Highway Administration,Washington, DC 205903. Terminology3.1 Definitions:3.1.1 axle, naxis oriented transversely

6、 to the nominaldirection of vehicle motion, and extending the full width of thevehicle, about which the axle wheels at both ends rotate.3.1.2 axle count, ntotal number of vehicle axles that areenumerated at a point on a lane or roadway during a specifiedtime interval.3.1.3 axle counter, ndevice that

7、 receives signals from anaxle sensor and indicates the cumulative number of axles thatwere detected by the sensor during a specified time interval.3.1.4 functional classification, na stratification of high-ways based on their common usage or function.3.1.5 machine count, nthe cumulative number of ax

8、les,vehicles, or vehicles within specified classes, or all of these,indicated or recorded by a traffic recording device for aspecified time interval.3.1.6 traffc counter, na device that indicates, and usuallyrecords, the number of vehicles or vehicle axles, or both, thatpass a point on a lane or roa

9、dway during a specified timeinterval.3.1.7 traffc recording device, na device that receivessignals from a sensor(s) and registers axle count, vehicle count,vehicle classification count, speed, gap, or headway (any or allof these) for defined time intervals.3.1.8 vehicle, nan assembly of one or more

10、mobile unitscoupled together for travel on a highway; a vehicle comprisesone powered unit and may include one or more unpoweredfull-trailer or semi-trailer unit(s).3.1.9 vehicle classification, nthe process of categorizingvehicles into various classes, usually according to their respec-tive axle or

11、mobile-unit(s) configuration.3.1.10 vehicle classification count, nthe cumulative num-ber of vehicles of each defined class, indicated or recorded fora specified time interval.3.2 Definitions of Terms Specific to This Standard:3.2.1 axle count adjustment factor, nthe number that whenmultiplied by an

12、 axle count (3.1.2) will adjust the axle count toan estimate of the total number of vehicles that produced theaxle count.3.2.1.1 DiscussionThe adjustment factor is sometimesbased upon the premise that: (1) the portion of all vehiclesincluded in each of various vehicle classes, and (2) therespective

13、average number of axles per vehicle class for thevehicles that produced the axle count being adjusted are knownor are assumed to be the same as the two corresponding valuesused to characterize the vehicles in a chosen, representative, orsimilar traffic stream.4. Summary of Practice4.1 Basic StepsDev

14、elopment of an axle count adjustmentfactor involves two basic steps: (1) defining a time intervalalong with the characteristics of the vehicles that comprised thetraffic stream during the time interval, and (2) obtaining thedata needed to characterize the vehicles in the traffic stream.1This practic

15、e is under the jurisdiction of ASTM Committee E17 on Vehicle -Pavement Systems and is the direct responsibility of Subcommittee E17.52 onTraffic Monitoring.Current edition approved Sept. 1, 2018. Published September 2018. Originallyapproved in 2005. Last previous edition approved in 2012 as E2467 05

16、 (2012).DOI: 10.1520/E2467-05R18.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Princ

17、iples for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1Depending upon the type of data available, one of the follow-ing methods may be used to calculate the factor.4.1.1 Direct MethodIf, for

18、a chosen time interval, re-corded data are available (e.g., from anASTM Type I and TypeII WIM system or from certain types of traffic counters ortraffic recordings devices) concerning the total number ofvehicles in the traffic stream concurrently with the total axlecount (3.1.2), the axle count adju

19、stment factor can be calcu-lated directly as the ratio of the two numbers. The total numberof vehicles in the traffic stream may be determined from arecorded machine count (3.1.5) or by summating the number ofvehicles in each applicable vehicle class as recorded in avehicle classification count (3.1

20、.10). This method of derivingan axle count adjustment factor is illustrated in Appendix X2.4.1.2 Alternative MethodIf specific data such as thatdescribed in 4.1.1 are not available for the chosen time interval,in order to develop an axle count adjustment factor, it might beexpeditious to characteriz

21、e the vehicles in a representative(presumed to be similar) traffic stream by obtaining for a timeinterval of the same duration as that for the axle count to beadjusted, concurrent data samples of: vehicle classificationcount, average number of axles per vehicle class, and total axlecount. The averag

22、e number of axles per vehicle class may beeither calculated from observed data or estimated from previ-ous experience.An example is shown in Table 1 for the averagenumber of axles per vehicle class (suggested by descriptions ofvehicles in each of the 13 vehicle classes defined in the TraffcMonitorin

23、g Guide. To derive the axle count adjustment factor,divide the sum of the vehicles in all classes (total number ofvehicles) by the sum of the products of the number of vehiclesin each class times the respective average number of axles pervehicle class (total number of axles). This alternative method

24、of deriving an axle count adjustment factor is illustrated inAppendix X1. The axle count adjustment factor developedfrom this method may be applied to an axle count when it isassumed that the traffic stream which produced the axle countbeing adjusted had essentially the same portion of vehicles inea

25、ch designated vehicle class and average number of axles pervehicle class as the traffic stream that was chosen to berepresentative.4.2 Time IntervalIt is recommended that a series of axlecount adjustment factors be developed for application to axlecounts taken during weekdays (Monday to Friday), wee

26、kends(Saturday and Sunday), months, quarters (either calendarquarters or seasonal quarters), and calendar year. Specialevents that produce significant traffic volumes and recurperiodically, such as festivals, fairs, and sporting events, mightjustify the development of a separate axle count adjustmen

27、tfactor for the specific time interval and locality.4.3 Vehicle CharacteristicsThe critical vehicle character-istic required for developing an axle count adjustment factor isthe number of axles on each individual vehicle that producedthe axle count to be adjusted, or a credible estimate thereof.Vari

28、ous sensor typesvehicle-presence, axle-passage, tire-presence, and othersare employed in various arrays andteamed with various signal-processing algorithms and trafficrecording devices to count vehicles, and sometimes count andclassify them according to their axle number and spacing, or toonly count

29、 axles with respect to time. Application of appropri-ate and capable traffic recording devices is required foracquiring data (with proper analysis) needed to develop an axlecount adjustment factor.4.4 ApplicationThe derived axle count adjustmentfactoralways less than 0.5may be correlated with otherp

30、arameters such as volume, density, speed, highway functionalclass, designated truck routes, parkways, and geographic localeto further describe the characteristics of the observed trafficstream and suggest potential future applications of the factorwhen only axle count for a similar traffic stream is

31、 known.5. Significance and Use5.1 This practice addresses the development of axle countadjustment factors, using axle counts and vehicle classificationcounts. This practice provides information for use with profes-sional judgment by governmental agencies and private firms inthe management of roads a

32、nd roadway traffic.5.2 Traffic monitoring is important to the safe and efficientmovement of people and goods. The purpose of this practice isto ensure that traffic monitoring procedures produce traffic dataand summary statistics that are adequate to satisfy diverse andcritical traffic information ne

33、eds.6. Keywords6.1 axle; axle count; traffic counter; vehicle; vehicle axles;vehicle classificationTABLE 1 Average Number of Axles per Vehicle ClassVehicleClassDescriptionAverageNumber ofAxles perVehicle1 Motorcycles 22 Passenger Cars 23 4-Tire Single-Unit Trucks 24 Buses 25 2-Axle, 6-Tire Single-Un

34、it Trucks 26 3-Axle Single-Unit Trucks 37 4 or More Axle Single-Unit Trucks 48 4 or Fewer Axle Single-Trailer Trucks 49 5-Axle Single-Trailer Trucks 510 6 or More Axle Single-Trailer Trucks 611 5 or Fewer Axle Multi-Trailer Trucks 512 6 Axle Multi-Trailer Trucks 613 7 or More Axle Multi-Axle Trucks

35、7E2467 05 (2018)2APPENDIXES(Nonmandatory Information)X1. SAMPLE CALCULATION OF AXLE COUNT ADJUSTMENT FACTOR BY ALTERNATIVE METHODX1.1 For a specified time interval, obtain a previous classi-fication count from the same section of roadway or a section ofroadway with similar traffic characteristics.X1

36、.2 Using data such as that illustrated in Table 1 as aguide, multiply the estimated average axles per vehicle class(e.g., Table X1.1, Col 2) by the vehicle count by class (Col 3)to determine the calculated axle count (Col 4) for each vehicleclass.X1.3 Determine the total axle count by summating thec

37、alculated axle counts for each vehicle class (total Col 4).X1.4 Summate all vehicle count by class (Col 3) to deter-mine the total vehicle count, and divide this total vehicle countby the total axle count (total Col 4) to determine the axle countadjustment factor.X1.4.1 As shown is Table X1.1, the t

38、otal vehicle count was10 507. Using the suggested average number of axles pervehicle, the total axle count was 33 086. By dividing theformer number by the latter number, the axle count adjustmentfactor of 0.3176 is determined.X1.5 If at some future time, only an axle count is taken atthis location o

39、n a weekday, e.g. 33 086 (or at another locationwith a similar mix of vehicle types and percentage of eachtype), the estimated number of vehicles that produced the axlecount would be calculated by multiplying the axle countadjustment factor of 0.3176 by the axle count of 33 086 to givean estimated 1

40、0 508 vehicles.X2. SAMPLE CALCULATION OF AXLE COUNT ADJUSTMENT FACTOR BY DIRECT METHODX2.1 In the situation where a traffic counter capable ofrecording vehicle counts is available at a site, an axle countermay be installed adjacent to it.X2.2 While one device is enumerating the total number ofvehicl

41、es, the other is enumerating the total number of axles.X2.3 At the end of the specified time period, the recordedvalues from the two devices should be recorded.X2.4 By dividing the total number of vehicles by the totalnumber of axles, the axle count adjustment factor is deter-mined.X2.5 Using Table

42、X1.1 as an example, only the Totals linewould be utilized.X2.5.1 The total vehicle count was determined to be 10 507,and the total axle count was determined to be 33 086.X2.5.2 By dividing the former by the latter, an axle countadjustment factor of 0.3176 is calculated.ASTM International takes no po

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44、lity.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to A

45、STM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the addres

46、s shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 61

47、0-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ X1.1 Example Weekday Traffic Count (Rural Interstate)1234VEHICLECLASSAVERAGEAXLES PERVEHICLECLASSVEHICLE COUNTBY CLASSCALCULATEDAXLE COUNT12002 2 3929 78583 2 2049 40984 2 68 1365 2 331 6626 3 139 417743128 4 355 14209 5 3122 15 61010 6 154 92411 5 249 124512 6 52 31213 7 56 392TOTALS 10 507 33 086E2467 05 (2018)3