1、Designation: E 2532 09Standard Test Methods forEvaluating Performance of Highway Traffic MonitoringDevices1This standard is issued under the fixed designation E 2532; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、 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 PurposeThe two test methods contained in this stan-dard define acceptance tests for evaluating the performance ofa Traffic
3、 Monitoring Device (TMD) according to the functionsit performs, the data it provides, the required accuracy of thedata, and the conditions under which the device operates.Acceptance tests are recommended whenever a TMD is pur-chased, installed, or performance validation is desired. Thetests are perf
4、ormed in a field environment and result in anaccept or a reject decision for the TMD under test.1.2 ExceptionsExceptions and options to the test methodsmay be included in any derivative test method presented by auser as part of the procurement process for TMDs. Sellers mayoffer exceptions and option
5、s in responding to an invitation tobid.1.3 UnitsThe values stated in inch-pound units are to beregarded as standard. The values given in parentheses aremathematical conversions to SI units,2which are provided forinformation only and are not considered standard.1.4 The following safety procedures app
6、ly to Sections 6 and7, which describe the details of the acceptance test methods.When a test site accessible by the public (for example, a streetor highway) is used for the acceptance test of the TMD, obtainapproval from the public authority having jurisdiction over thesite for the traffic control p
7、rocedures to be used during the test.This standard does not purport to address all of the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations
8、 prior to use.2. Referenced Documents2.1 ASTM Standards:3E 177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE 867 Terminology Relating to Vehicle-Pavement SystemsE 1318 Specification for Highway Weigh-In-Motion (WIM)Systems with User Requirements and Test MethodsE 2300 Specifi
9、cation for Highway Traffic Monitoring De-vices3. Terminology3.1 Definitions of terms and definitions of terms specific tothese test methods are given below.3.2 Definitions:3.2.1 accepted reference value, nvalue attributed to aparticular quantity (for example, vehicle class by number ofaxles and inte
10、raxle spacings, vehicle count, lane occupancy, orvehicle speed) and agreed upon by the user and seller inadvance of testing of a TMD, which has an uncertaintyappropriate for the given purpose. E 23003.2.2 accuracy, ncloseness of agreement between a valueindicated by a TMD and an accepted reference v
11、alue.E 23003.2.3 axle, naxis oriented transversely to the nominaldirection of vehicle motion, and extending the full width of thevehicle, about which the wheels at both ends rotate. E 867,E 13183.2.4 axle count, nnumber of vehicle axles enumerated ata point on a lane or roadway during a specified ti
12、me interval.E 8673.2.5 bias, na generic concept related to a consistent orsystematic difference between a set of test results from theprocess and an accepted reference value of the property beingmeasured. E 1773.2.6 correct detection, nan indication by a TMD that avehicle actually passing over the d
13、etection area of the TMD is1These test methods are under the jurisdiction of ASTM Committee E17 onVehicle - Pavement Systems and are the direct responsibility of SubcommitteeE17.52 on Traffic Monitoring.Current edition approved July 1, 2009. Published July 2009. Originally approvedin 2006. Last prev
14、ious edition approved in 2006 as E 2532 06.2Standard Practice for Use of the International System of Units (SI): TheModern Metric System, IEEE/ASTM SI 10TM-2002, The Institute of Electrical andElectronics Engineers (IEEE), Inc., 3 Park Avenue, New York, NY, 10016-5997,USA and American Society for Te
15、sting and Materials (ASTM), 100 Barr HarborDrive, West Conshohocken, PA 19428-2959, USA, ISBN 0-7381-3317-5.3For 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 stan
16、dards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.detected by the TMD. E 23003.2.7 data item, ncharacteristic associated with individualvehicles (for example, count, class, and speed) or t
17、he con-tinuum of vehicles at a location (for example, density, flowrate, and queue length). E 23003.2.8 detection area, nroad surface area above which asensor detects a vehicle or vehicle component. E 23003.2.9 electronics unit, ndevice that provides power to oneor more sensors, filters and amplifie
18、s the signals produced bythe sensors, and may perform other functions such as sensitiv-ity adjustment, failure indication, and delayed actuation oftraffic control signals.4E 23003.2.10 false detection, nan indication by a TMD that avehicle not actually passing over the detection area of the TMDis de
19、tected by the TMD. E 23003.2.11 flow rate, nnumber of vehicles passing a givenpoint or section of a lane or roadway during a designated timeinterval, usually 15 min, but expressed as an equivalent hourlyrate in vehicles/h. E 23003.2.12 lane occupancy, npercent of selected time intervalthat vehicles
20、are detected in the detection area of a sensor; thetime interval during which the lane occupancy is measured isusually 20 to 30 s.5E 23003.2.13 missed detection, nan indication by a TMD that avehicle actually passing over the detection area of the TMD isnot detected by the TMD. E 23003.2.14 precisio
21、n, na generic concept related to the close-ness of agreement between test results obtained under pre-scribed like conditions from the measurement process beingevaluated. E 1773.2.15 sensor, ndevice for acquiring a signal that providesdata to indicate the presence or passage of a vehicle or of avehic
22、le component over the detection area with respect to time(for example, flow rate or number of axles and their spacing),or one or more distinctive features of the vehicle such as heightor mass. E 23003.2.16 speed, nrate of vehicle motion expressed as dis-tance per unit of time. E 23003.2.17 time stam
23、p, nrecorded date and time at which ameasurement was made; information and format may betailored to the application, but usually consists of month, day,year, hour, minute, second, and subsecond. E 23003.2.18 tolerance, nallowable deviation of a value indi-cated by the device under test or a device i
24、n service from anaccepted reference value. E 23003.2.19 traffc monitoring device, nequipment that countsand classifies vehicles and measures vehicle flow characteris-tics such as vehicle speed, lane occupancy, turning movements,and other parameters typically used to portray traffic move-ment. E 2300
25、3.2.20 vehicle class by axle, ncharacterization of a ve-hicle by its number of axles and interaxle spacings. E 23003.2.21 vehicle class by length, ncharacterization of ve-hicles by their total length. E 23003.2.22 vehicle count (volume), ntotal number of vehiclesobserved or predicted to pass a point
26、 on a lane or roadwayduring a specified time interval. E 23003.2.23 vehicle, none or more mobile units coupled to-gether for travel on a highway; a vehicle contains one poweredunit and may include one or more non-powered full-trailer orsemi-trailer units. E 8673.2.24 vehicle passage, nsensor output
27、pulse signal pro-duced when an initial vehicle detection is made in the detectionarea of the sensor. E 23003.2.25 vehicle presence, nsensor output signal producedthe entire time a vehicle is detected in the detection area of thesensor. E 23003.3 Definitions of Terms Specific to This Standard:3.3.1 a
28、liasing, nphenomenon that occurs when a signalcontaining frequencies greater than one half the samplingfrequency is digitized, causing those frequencies in excess ofone half the sampling frequency to be folded back into thedigitized signal spectrum.3.3.2 straddling vehicle, na vehicle that has one o
29、r moretires in an adjacent lane or shoulder.3.3.3 vehicle density, nnumber of vehicles occupying agiven length of a lane or roadway at a particular instant, usuallyexpressed in units of vehicles/lane-mile (lane-km).4. Summary of Acceptance Test Methods4.1 Two categories of acceptance tests are descr
30、ibed. Thefirst, the Type-approval Test, is intended for TMDs that havenever been type approved. The second, the On-site VerificationTest, is applicable to production versions of TMDs that havepreviously passed a Type-approval Test, but are now beinginstalled at a new location or have been repaired.
31、Fig. 1illustrates the procedure for determining which of the tests isapplicable. The rigorous Type-approval Test verifies the func-tionality of all features of the TMD and provides informationfor evaluating the accuracy of the data item outputs whenmonitoring vehicle flows consisting of a mix of all
32、 anticipatedvehicle classes under a specified range of operating conditions.The On-site Verification Test provides the TMD user and sellerwith a means for determining whether the production versionof a TMD installed at a particular site meets the performanceand user requirements identified in Specif
33、ication E 2300. Bothcategories of acceptance tests compare the outputs of the TMDunder test with those of equipment that produce acceptablereference values. If all features of the TMD function properlyand the output data are within the agreed upon tolerances, thenthe TMD is reported to have passed t
34、he acceptance test. If not,the TMD is reported to have failed the test.5. Device Classification5.1 Type, Tolerance, and Operating ConditionsThe type,tolerance, and operating conditions of the TMD to be testedshall be specified according to Specification E 2300.5.2 Use of Measured Data in Support of
35、OtherApplicationsAdditional vehicle flow parameters may be4Klein, L.A., Gibson, D., and Mills, M.K., Traffc Detector Handbook: ThirdEdition , FHWA-HRT-06-108 (Vol. I) and FHWA-HRT-06-139 (Vol. II), U.S.Department of Transportation, Federal Highway Administration, Washington, DC,Oct. 2006. Also avail
36、able at: http:/www.tfhrc.gov/its/pubs/06108/ and http:/www.tfhrc.gov/its/pubs/06139/5Different sensor models or technologies used to measure lane occupancy mayhave different detection area sizes and, hence, produce different occupancy values,although all devices are operating properly.E2532092calcul
37、ated from the recorded data.Among these parameters arevehicle flow rate, density, headway, intersection delay, vehiclegap in time or distance, queue length, and turning movements.Other highway system performance measures, such as volume-to-capacity ratio, total vehicle hours traveled, total vehiclem
38、iles traveled, average travel speed, number and categories ofaccidents, pollutant emissions, and fuel consumption may alsobe calculated from data recorded by appropriate sensors. Thesetest methods do not address the ability of the TMD to calculateor provide data for these additional vehicle flow par
39、ameters orhighway system performance measures.6. Standardization of Acceptance Test Conditions6.1 Installation RequirementsIt shall be the responsibilityof the user to install the TMD under test in accordance with themanufacturers requirements. Conditions that are typicallyspecified when installing
40、and evaluating TMDs are describedin 6.2 through 6.9.6.2 Vehicle Flow Rates and Vehicle ClassesThe TMDshall be tested under flow rates that include vehicle-to-vehiclegaps both less than and greater than 1 s and a mix of vehicleclasses characteristic of the operating conditions in which thedevice will
41、 be used. The vehicle classes shall be specified bythe user.6.3 LightingThe TMD shall be tested under lightingcharacteristic of the operating conditions in which the devicewill be used. Lighting conditions may include day, night, dawn,dusk, and other hours where artifacts or unusual conditionssuch a
42、s shadows and sun glint occur. The lighting conditionsand times of day for the test will depend on the technologyused in the TMD under test. The user shall specify the specificlighting conditions, if any, required for the tests. Table 1contains lighting and environmental factors that shall beconside
43、red when evaluating TMDs.6.4 TemperatureThe user shall specify the maximum andminimum ambient air temperatures in which the TMD undertest (including sensor components installed on, under, or abovethe roadway and components installed in roadside cabinets) isexpected to operate properly and under whic
44、h it will be tested.6.5 Other Environmental ConditionsThe user shallspecify other environmental conditions under which the TMDshall be tested. These include rain and rain rates, fog andvisibility range, snow and snowfall rate, wind-borne dust,movement caused by wind and vibration, and any othercondi
45、tions that are perceived by the user to affect the perfor-mance of the TMD.FIG. 1 Process for Determining Applicable TMD Acceptance TestTABLE 1 Lighting and Weather Factors That May be Included asPart of TMD TestingLighting and Weather FactorsA1. Dawn ambient lighting2. Dusk ambient lighting3. Night
46、time ambient lighting4. Sun glint5. Rain characterized by rain rate6. Fog or dust characterized by human visual range7. Snow characterized by snow fall rate and snow flake sizeAData gathered to verify TMD operation under these conditions may begathered simultaneously with data used to verify operati
47、on at the vehicle flow ratesand mix of vehicle classes specified in 6.2.E25320936.6 Evidence that TMD can Operate Under Specified Envi-ronmental ConditionsIf applicable, the seller shall supplyevidence that the device offered has been tested and foundcapable of operating under the specified environm
48、ental condi-tions.6.7 PowerThe user shall provide and maintain electricalpower at each test site or specify an optional power source thatcan supply the power required by the TMD and the datarecording equipment.6.8 Data and Video CommunicationIf specified, the usershall provide and maintain an adequa
49、te data and video com-munication link between the test site and the data recordingequipment. This link may also transmit information to monitorthe performance of the TMD under test and adjust its settings,if applicable. Such a communications link may be wireless.TMD output data and video shall be recorded in a synchronizedmanner as specified by the user to support TMD evaluation.6.9 Options, Exceptions, and Added FeaturesAny desiredoptions, exceptions, or added data display or data recordingfeatures needed to evaluate the performance re
