1、Designation: E 1318 09Standard 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 () 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 thro
4、ughconnectors 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 Ot
5、her 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 or
6、 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 toti
7、re-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 ty
8、pes 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 pr
9、ocurement process for WIM equipment or services, andvendors may offer exceptions and options in responding to aninvitation to bid.1.4 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for inf
10、ormation onlyand are not considered standard.21.5 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 userof t
11、his standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to use.2. Referenced Documents2.1 ASTM Standards:3E 867 Terminology Relating to Vehicle-Pavement Systems2.2 AASHTO Standards:4Interim Guide for Design of Pavement Structu
12、res1972,1981Guide for Design of Pavement Structures1986, 19933. 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 thereof, by measurement a
13、nd analysis of dynamicvehicle tire forces. (See Terminology E 867)3.2 Definitions of Terms Specific to This Standard:1This specification is under the jurisdiction ofASTM Committee E17 on Vehicle- Pavement Systems and is the direct responsibility of Subcommittee E17.52 onTraffic Monitoring.Current ed
14、ition approved Feb. 1, 2009. Published February 2009. Originallyapproved in 1990. Last previous edition approved in 2002 as E 1318 02.2ASTM SI10 - 02 IEEE/ASTM SI 10American National Standard for Use of theInternational System of Units (SI): The Modern Metric System, The Institute ofElectrical and E
15、lectronics Engineers, Inc., 1828 L. St. NW, Suite 1202, Washington,DC 200365101,USA, and ASTM International, 100 Barr Harbor Drive, WestConshohocken, PA 19428-2959, USA, www.astm.org.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.
16、org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Available from American Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.1
17、Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1 accuracy, nthe closeness or degree of agreement(satisfies a stated tolerance and percent compliance) between avalue measured or estimated by a WIM system and an acceptedreference v
18、alue.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 loadsof the wheels on a defined group of adjacent axles; a portion
19、 ofthe gross-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 portion of the gross-vehicle weight.3.2.5 dynamic vehicle tir
20、e 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 influences such as roadsurface roughness, vehicle acceleration, o
21、ut-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 the measured dynamicvehicle tire force in units of mass, lb (k
22、g). (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-axle load, lb (kg), nthe load transmitted tothe road surface
23、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-mitted to the road surface by the tires on all wheels of two
24、consecutive 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 of weighing,expressed in units of mass, due only to the verti
25、cally-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 load, lb (kg), nthe total load transmit-ted to the road surfa
26、ce 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; also called tridem-axle load.3.2.12 weigh, v trto measure the tire load on one or moretires by using a vehicle scale, an axle-
27、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 standard test weights at each
28、 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 acceleration offree fall.23.2.13.1 Disc
29、ussionThe 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 collecting statisticalinformation a
30、re 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 adopted by ISO is 32.174049 f
31、t/s2(9.806 65 m/s2). Weight is a special case of force, asweight is due only to the local force of gravity, which is alwaysdirected vertically downwards. For purposes of this specifica-tion, and in accordance with common weighing practice, theWIM System shall be adjusted or calibrated to indicate th
32、emagnitude 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 wheelbase, ft (m), nthe distance between the front-most and the rear-most axles on a vehicle
33、or combination thathas the tires on these axles in contact with the road surface atthe time of weighing.3.2.15 wheel load, lb (kg), nthe sum of the tire loads onall tires included in the wheel assembly on one end of an axle;a wheel assembly may have a single tire or dual tires.3.2.16 WIM System, na
34、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 tire loads; calculate speed, axlespacing, wheelbase, vehicle class according to axle arrange-ment, and other parameters conce
35、rning the vehicle; and pro-cess, display, store, and transmit this information. This stan-dard applies only to highway vehicles.4. Classification4.1 TypesWIM systems shall be specified to meet theneeds of the user for intended applications in accordance withthe following types. Exceptions and option
36、s 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 affectedsystem components shall be provided by the vendor. The usermay specify as options a completely batter
37、y-powered system orbattery-backup power in case of failure of normal power. All5The boldface numbers given in parentheses refer to a list of references at theend of the text.E1318092systems shall allow the user to select at the beginning of eachdata-taking session the units of measurement: either U.
38、S.customary units or SI units.2The 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 recommendsexpre
39、ssing 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-collectionsite an
40、d 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. Provisions shall be made forentering selected limits and tolerances for wheel, axle, axle-group (inc
41、luding bridge-formula grouping (2) loads, gross-vehicle weight, and speed, and for detecting and indicatingsuspected violation of any of these limits by a particularvehicle. A feature shall be provided so that the user candetermine whether or not the WIM system will prepareselected data items for di
42、splay and recording. Use of thisfeature shall not inhibit the system from receiving and process-ing data. Data shall be processed on-site in such a way that alldata items shown in Table 1, except Item 13, can be displayedin alphanumeric form for immediate review. This may beaccomplished by connectin
43、g a portable (for example, laptop)computer, furnished and supported by the vendor as a part ofthe WIM-system equipment, directly to the on-site instruments.Software on the host computer that supports the WIM systemshall calculate ESALs (Item 13 in Table 1) as described at 5.9.Means shall be provided
44、 for temporary, on-site storage of DataItems 1, 5, 6, 8, 9, 10, and 11 for each vehicle processed by theWIM system, or for only those vehicles with a front-axle or afront-wheel load that equals or exceeds a threshold value setinto the on-site system by the user at the beginning of adata-taking sessi
45、on, for example, 2000 lb (900 kg) wheel load.To any vehicle record for which Data Items 1, 5, 6, 8, 9, 10, and11 are to be stored, an invalid-measurement code shall beassigned when (1) the left-side and right-side wheel loads foran axle have a difference of 40 % or more; and (2) either of thewheel l
46、oads for such axle equals or exceeds 2000 lb (900 kg).Both the 40 % and the 2000 lb (900 kg) values shall beprogrammable by the user. Also, means shall be provided forrapid, efficient transfer of these data to files made available ona compatible host computer (furnished by either the user or thevend
47、or, as specified for the specific site by the user) at a remotelocation according to an appropriate time schedule and dataformat specified by the user. The vendor shall furnish, docu-ment, and support software for use on the host computer forprocessing the transferred data items in such a way that a
48、ll dataitems shown in Table 1 can be displayed in alphanumeric formfor immediate review and subsequent use by the host computeruser. This same software shall be provided on the portablecomputer for use when it is processing data during calibrationand testing. On-site presentation of a hard-copy of a
49、ll dataitems produced by 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 lanes 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
