1、Designation: E 1318 02Standard Specification forHighway Weigh-In-Motion (WIM) Systems with UserRequirements and Test Methods1This standard is issued under the fixed designation E 1318; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision
2、, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 Weigh-In-MotionThis specification describes Weigh-In-Motion (WIM), the process of measuring the dynamic
3、 tireforces of a moving vehicle and estimating the correspondingtire loads of the static vehicle. Gross-vehicle weight of ahighway vehicle is due only to the local force of gravity actingupon the composite mass of all connected vehicle components,and is distributed among the tires of the vehicle thr
4、oughconnectors such as springs, motion dampers, and hinges.Highway WIM systems are capable of estimating the grossweight of a vehicle as well as the portion of this weight, calledload in this specification, that is carried by the tires of eachwheel assembly, axle, and axle group on the vehicle.1.2 O
5、ther Traffc DataAncillary traffic data concerningthe speed, lane of operation, date and time of passage, numberand spacing of axles, and classification (according to axlearrangement) of each vehicle that is weighed in motion isdesired for certain purposes. It is feasible for a WIM system tomeasure o
6、r calculate these traffic parameters and to process,summarize, store, display, record, hard-copy, and transmit theresulting data. Furthermore, differences in measured or calcu-lated parameters as compared with selected control criteria canbe detected and indicated to aid enforcement. In addition tot
7、ire-load information, a WIM system is capable of producingall, or specified portions of, these traffic data.1.3 Standard SpecificationHighway WIM systems gener-ally have three applications: collecting statistical traffic data,aiding enforcement, and enforcement. This specification clas-sifies four t
8、ypes of WIM systems according to their applicationand details their respective functional, performance, and userrequirements. It is a performance-type (end product-type)specification. Exceptions and options to the specification maybe included in any specification prepared by the user as part ofthe p
9、rocurement process for WIM equipment or services, andvendors may offer exceptions and options in responding to aninvitation to bid.1.4 UnitsThe values stated in inch-pound units are to beregarded as standard. The values given in parentheses aremathematical conversions to SI units2which are provided
10、forinformation only and are not considered standard.1.5 The following precautionary caveat applies only to thetest method portion, Section 7, of this specification. Thisstandard does not purport to address all of the safety concerns,if any, associated with its use. It is the responsibility of the us
11、erof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:E 867 Terminology Relating to Vehicle-Pavement Systems32.2 AASHTO Standards:AASHO Interim Guide for Design of Pavem
12、ent Structures1972, 19814AASHTO Guide for Design of Pavement Structures1986,199343. Terminology3.1 Definitions:3.1.1 weigh-in-motion (WIM), nthe process of estimatinga moving vehicles gross weight and the portion of that weightthat is carried by each wheel, axle, or axle group, or combi-nation there
13、of, by measurement and analysis of dynamicvehicle tire forces. (See Terminology E 867)3.2 Definitions of Terms Specific to This Standard:3.2.1 accuracy, nthe closeness or degree of agreement(within a stated tolerance and probability of conformity)between a value measured or estimated by a WIM system
14、 andan accepted reference value.3.2.2 axle, nthe axis oriented transversely to the nominaldirection of vehicle motion, and extending the full width of thevehicle, about which the wheel(s) at both ends rotate.3.2.3 axle-group load, lb (kg), nthe sum of all tire loads1This specification is under the j
15、urisdiction of ASTM Committee E17 onVehicle-Pavement Systems and is the direct responsibility of Subcommittee E17.52on Traffic Monitoring.Current edition approved Jan. 10, 2002. Published February 2002. Originallypublished as E 1318 90. Last previous edition E 1318 00e1.2Standard Practice for Use of
16、 the International System of Units (SI): TheModern Metric System, IEEE/ASTM SI 10-1997, The Institute of Electrical andElectronics Engineers, Inc., 1828 L. St. NW, Suite 1202, Washington, DC200365101,USA, and ASTM International, 100 Barr Harbor Drive, West Consho-hocken, PA 19428-2959, USA, ISBN 1-5
17、5937-901-4.3Annual Book of ASTM Standards, Vol 04.03.4Available from American Association of State Highway and TransportationOfficials, 444 N. Capitol St., NW, Suite 249, Washington, DC 20001.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United
18、States.of the wheels on a group of adjacent axles; a portion of thegross-vehicle weight.3.2.3.1 DiscussionAn axle group can be defined in termsof the number of axles included in the group and theirrespective interspaces.3.2.4 axle load lb (kg), nthe sum of all tire loads of thewheels on an axle; a p
19、ortion of the gross-vehicle weight.3.2.5 dynamic vehicle tire force, lb (kg), nthe compo-nent of the time-varying force applied perpendicularly to theroad surface by the tire of a moving vehicle.3.2.5.1 DiscussionIn addition to the force of gravity, thisforce can include the dynamic effects of influ
20、ences such as roadsurface roughness, vehicle acceleration, out-of-round tires,dynamically-unbalanced wheels, tire inflation pressure, vehiclesuspension and aerodynamic features, and wind. For purposesof this specification, the WIM System shall be adjusted orcalibrated to indicate the magnitude of th
21、e measured dynamicvehicle tire force in units of mass, lb (kg). (See 3.2.13.1).3.2.6 gross-vehicle weight, lb (kg), nthe total weight ofthe vehicle or the vehicle combination including all connectedcomponents; also, the sum of the tire loads of all wheels on thevehicle. (See 3.2.13.1).3.2.7 single-a
22、xle load, lb (kg), nthe load transmitted tothe road surface by the tires of all wheels lying between twoparallel transverse vertical planes 3.3 ft (1 m) apart, extendingacross the full width of the vehicle; a portion of the gross-vehicle weight.3.2.8 tandem-axle load, lb (kg), nthe total load trans-
23、mitted to the road surface by the tires on all wheels of twoconsecutive vehicle axles that are more than 3.3 ft (1 m) andnot more than 8 ft (2.4 m) apart; a portion of the gross-vehicleweight.3.2.9 tire load, lb (kg), nthe portion of the gross-vehicleweight imposed upon the static tire at the time o
24、f weighing,expressed in units of mass, due only to the vertically-downward force of gravity acting on the total mass of the staticvehicle.3.2.10 tolerance, nthe defined limit of allowable depar-ture of a value measured or estimated by a WIM system froman accepted reference value.3.2.11 triple-axle l
25、oad, lb (kg), nthe total load transmit-ted to the road surface by the tires on all wheels of threeconsecutive vehicle axles, with not more than 12 ft (3.7 m)between the two axles furthest apart; a portion of the gross-vehicle weight.3.2.12 weigh, v trto measure the tire load on one or moretires by u
26、sing a vehicle scale, an axle-load scale, a portableaxle-load weigher, or a wheel-load weigher.3.2.12.1 DiscussionRefer to Sec. 2.20, of National Insti-tute of Standards and Technology (NIST) Handbook 44 (1)5fora definition of each type of weighing device. These devices areusually subjected to field
27、 standard test weights at each localityof use and are adjusted to indicate units of mass (See Sec. 3.2,Appendix B, NIST Handbook 44).3.2.13 weight, lb (kg), nthe external force of gravityacting vertically downwards upon a body with a magnitudeequal to the bodys mass multiplied by the local accelerat
28、ion offree fall.23.2.13.1 DiscussionThe force of gravitythus, the accel-eration of free fallis different at various locations on or nearthe surface of Earth; therefore, weighing devices in commer-cial use or in official use by government agencies for enforce-ment of traffic and highway laws or colle
29、cting statisticalinformation are usually used in one locality and are adjusted orcalibrated to indicate mass at that locality. (1) The indicatedmass can be converted to weight (in units of force) bymultiplying by the local value of the acceleration of free fall, ifit is known. The conventional value
30、 adopted by ISO is 32.174049 ft/s2(9.806 65 m/s2). Weight is a special case of force, asweight is due only to the local force of gravity, that is alwaysdirected vertically downwards. For purposes of this specifica-tion, and in accordance with common weighing practice, theWIM System shall be adjusted
31、 or calibrated to indicate themagnitude of estimated weight and load in units of mass,pounds avoirdupois (kilograms), and the direction of theassociated force vector will always be downwards toward theapproximate center of Earth.3.2.14 wheel load, lb (kg), nthe sum of the tire loads onall tires incl
32、uded in the wheel assembly on one end of an axle;a wheel assembly may have a single tire or dual tires.3.2.15 WIM System, na set of sensors and supportinginstruments that measure the presence of a moving vehicle andthe related dynamic tire forces at specified locations withrespect to time; estimate
33、tire loads; calculate speed, axlespacing, vehicle class according to axle arrangement, and otherparameters concerning the vehicle; and process, display, store,and transmit this information. This standard applies only tohighway vehicles.4. Classification4.1 TypesWIM systems shall be specified to meet
34、 theneeds of the user for intended applications in accordance withthe following types. Exceptions and options may be specified(See 1.3). All systems shall be designed to operate with thelocal electrical power of the country (that is, 110V, ac, 60-Hzpower in North America). Lightning protection for a
35、ffectedsystem components shall be provided by the vendor. The usermay specify as options a completely battery-powered system orbattery-backup power in case of failure of normal power. Allsystems shall allow the user to select at the beginning of eachdata-taking session the units of measurement: eith
36、er U.S.customary units or SI units2. The units setting shall remainwhere last assigned unless changed by the user at the beginningof a data-taking session. Load and weight values shall beexpressed in units of mass: pounds avoirdupois in U.S.customary units, or kilograms in SI units. The SI recommend
37、sexpressing large values of mass in megagrams, Mg. In com-mercial usage, which includes most applications and interpre-tations of WIM data, 1 Mg = 1000 kg = 1 metric ton = 1 tonne.4.1.1 Type IThis type of WIM system shall be designedfor installation in one or more lanes at a traffic data-collections
38、ite and shall be capable of accommodating highway vehiclesmoving at speeds from 10 to 80 mph (16 to 130 km/h),inclusive. For each vehicle processed, the system shall produceall data items shown in Table 1. A user-controlled feature of the5The boldface numbers given in parentheses refer to a list of
39、references at theend of the text.E 13182system shall allow tire-force information from the wheel(s) ononly one end of an axle to be used to estimate axle load.Provisions shall be made for entering selected limits andtolerances for wheel, axle, axle-group (including bridge-formula grouping (2) loads,
40、 and gross-vehicle weights as wellas speed, and for detecting and indicating suspected violationof any of these limits by a particular vehicle. A feature shall beprovided so that the user can determine whether or not theWIM system will prepare selected data items for display andrecording. Use of thi
41、s feature shall not inhibit the system fromreceiving and processing data. Data shall be processed on-sitein such a way that all data items shown in Table 1 can bedisplayed in alphanumeric form for immediate review. Thismay be accomplished by connecting a portable (for example,laptop) computer, furni
42、shed and supported by the vendor as apart of the WIM-system equipment, directly to the on-siteinstruments. Means shall be provided for temporary, on-sitestorage of data items 1, 5, 6, 8, 9, 10, and 11 for each vehicleprocessed by the WIM system, or for only those vehicles witha front-axle or front-w
43、heel load that exceeds a value set into theon-site system by the user at the beginning of a data-takingsession. Also, means shall be provided for rapid, efficienttransfer of these data to files made available on a compatiblehost computer (furnished by either the user or the vendor, asspecified for t
44、he specific site by the user) at a remote locationaccording to an appropriate time schedule and data formatspecified by the user. The vendor shall furnish, document, andsupport software for use on the host computer for processingthe transferred data items in such a way that all data itemsshown in Ta
45、ble 1 can be displayed in alphanumeric form forimmediate review and subsequent use by the host computeruser. This same software shall be provided on the portablecomputer for use when it is connected directly to the on-siteinstruments. On-site presentation of a hard-copy of all dataitems produced by
46、the system shall be an optional feature(Option 1) of the system. Option 2 for this type of WIM systemshall additionally provide means for counting and for recordinghourly the lane-wise count of all vehicles traveling in eachlane, up to a maximum of ten lanes, at a data-collection site,including lane
47、s without WIM sensors. Option 3 shall providefor counting, classifying (via axle arrangement), measuring thespeed of, and recording the hourly totals concerning all suchvehicles by class (according to axle arrangement) and by laneof travel.4.1.2 Type IIThis type of WIM system shall be designedfor in
48、stallation in one or more lanes at traffic data-collectionsites and should be capable of accommodating highwayvehicles moving at speeds from 15 to 80 mph (24 to 130 km/h),inclusive. For each vehicle processed, all data items shown inTable 1 except Item 1 shall be produced by the system. Allother fea
49、tures and options of the Type II WIM system shall beidentical to those described in 4.1.1 for the Type I WIMsystem.4.1.3 Type IIIThis type of WIM system shall be designedwith sensors installed in one or more lanes off the mainhighway lanes at weight-enforcement stations, or in one ormore main highway lanes, to identify vehicles operating atspeeds from 10 to 80 mph (16 to 130 km/h), inclusive, that aresuspected of weight-limit or load-limit violation. When thesensors are installed in the main highway lane(s), the Type IIIsyste
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