1、Designation: E 2532 06Standard 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 (e) 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 Traffi
3、c 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 per
4、formed 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 optio
5、ns 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 ap
6、ply 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
7、procedures 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 regulatorylimitation
8、s 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 Specif
9、ication 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 int
10、eraxle 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
11、value.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 t
12、ime 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 1771These test methods are under the jurisdiction of ASTM Committee E17 onVehicle - Pavement
13、 Systems and are the direct responsibility of SubcommitteeE17.52 on Traffic Monitoring.Current edition approved Dec. 1, 2006. Published January 2007.2Standard Practice for Use of the International System of Units (SI): TheModern Metric System, IEEE/ASTM SI 10TM-2002, The Institute of Electrical andE
14、lectronics Engineers (IEEE), Inc., 3 Park Avenue, New York, NY, 10016-5997,USA and American Society for Testing 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 C
15、ustomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.6 data item, ncharacteristic
16、 associated with individualvehicles (for example, count, class, and speed) or the con-tinuum of vehicles at a location (for example, density, flowrate, and queue length). E 23003.2.7 detection area, nroad surface area above which asensor detects a vehicle or vehicle component. E 23003.2.8 electronic
17、s unit, ndevice that provides power to oneor more sensors, filters and amplifies the signals produced bythe sensors, and may perform other functions such as sensitiv-ity adjustment, failure indication, and delayed actuation oftraffic control signals.4E 23003.2.9 flow rate, nnumber of vehicles passin
18、g a given pointor section of a lane or roadway during a designated timeinterval, usually 15 min, but expressed as an equivalent hourlyrate in vehicles/h. E 23003.2.10 lane occupancy, npercent of selected time intervalthat vehicles are detected in the detection area of a sensor; thetime interval duri
19、ng which the lane occupancy is measured isusually 20 to 30 s.5E 23003.2.11 precision, 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 1773.2.12 sensor, ndevice for acquiring a sig
20、nal that providesdata to indicate the presence or passage of a vehicle or of avehicle component over the detection area with respect to time(for example, vehicle flow, number of axles and their spacing),or perhaps one or more distinctive features of the vehicle suchas height or mass. E 23003.2.13 sp
21、eed, nrate of vehicle motion expressed as dis-tance per unit of time. E 23003.2.14 time stamp, 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 23003.2.15
22、tolerance, nallowable deviation of a value indi-cated by the device under test or a device in service from anaccepted reference value. E 23003.2.16 traffc monitoring device, nequipment that countsand classifies vehicles and measures vehicle flow characteris-tics such as vehicle speed, lane occupancy
23、, turning movements,and other parameters typically used to portray traffic move-ment. E 23003.2.17 vehicle class by axle, ncharacterization of a ve-hicle by its number of axles and interaxle spacings. E 23003.2.18 vehicle class by length, ncharacterization of ve-hicles by their total length. E 23003
24、.2.19 vehicle count (volume), ntotal number of vehiclesobserved or predicted to pass a point on a lane or roadwayduring a specified time interval. E 23003.2.20 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
25、 non-powered full-trailer orsemi-trailer units. E 8673.2.21 vehicle passage, nsensor output pulse signal pro-duced when an initial vehicle detection is made in the detectionarea of the sensor. E 23003.2.22 vehicle presence, nsensor output signal producedthe entire time a vehicle is detected in the d
26、etection area of thesensor. E 23003.3 Definitions of Terms Specific to This Standard:3.3.1 aliasing, 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 folde
27、d back into thedigitized signal spectrum.3.3.2 straddling vehicle, na vehicle that has one or 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 (la
28、ne-km).4. Summary of Acceptance Test Methods4.1 Two categories of acceptance tests are described. 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 passe
29、d a Type-approval Test, but are now beinginstalled at a new location or have been repaired. 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 t
30、he accuracy of the data item outputs whenmonitoring vehicle flows consisting of a mix of all 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 in
31、stalled at a particular site meets the performanceand user requirements identified in Specification 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
32、 output data are within the agreed upon tolerances, thenthe TMD is reported to have passed the 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 tested
33、shall be specified according to Specification E 2300.5.2 Use of Measured Data in Support of OtherApplicationsAdditional vehicle flow parameters may becalculated from the recorded data.Among these parameters arevehicle flow rate, density, headway, intersection delay, vehiclegap in time or distance, q
34、ueue length, and turning movements.Other highway system performance measures, such as volume-to-capacity ratio, total vehicle hours traveled, total vehiclemiles traveled, average travel speed, number and categories ofaccidents, pollutant emissions, and fuel consumption may alsobe calculated from dat
35、a recorded by appropriate sensors. Thesetest methods do not address the ability of the TMD to calculate4Klein, L. A., Mills, M. K., and Gibson, D. R. P., Traffc Detector Handbook,FHWA-HRT-06-108, U.S. Department of Transportation, Federal Highway Admin-istration, Washington, DC, 2006.5Different sens
36、or 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.E2532062or provide data for these additional vehicle flow parameters orhighway system performance measures.6. Sta
37、ndardization 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 and evaluating TMDs are describedin 6.2 through 6.9.
38、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 be used. The vehicle classes shall be specified byt
39、he 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 as shadows and sun glint occur. The lighting conditio
40、nsand 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 beconsidered when evaluating TMDs.6.4 TemperatureThe user sha
41、ll 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 which it will be tested.6.5 Other Environmental Conditio
42、nsThe 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 otherconditions that are perceived by the user to affect the p
43、erfor-mance of the TMD.6.6 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 environmental condi-tions.6.7 PowerThe user shall provide and mai
44、ntain electricalpower at each test site or specify an optional power source thatcan supply the power required by the TMD and the datarecording equipment.FIG. 1 Process for Determining Applicable TMD Acceptance TestTABLE 1 Lighting and Weather Factors That May be Included asPart of TMD TestingLightin
45、g and Weather FactorsA1. Dawn ambient lighting2. Dusk ambient lighting3. Nighttime 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 t
46、hese conditions may begathered simultaneously with data used to verify operation at the vehicle flow ratesand mix of vehicle classes specified in 6.2.E25320636.8 Data CommunicationIf specified, the user shall pro-vide and maintain an adequate data communication linkbetween the test site and the data
47、 recording equipment. Thislink may also transmit information to monitor the performanceof the TMD under test and adjust its settings, if applicable.TMD output data shall be recorded in a manner specified by theuser.6.9 Options, Exceptions, and Added FeaturesAny desiredoptions, exceptions, or added d
48、ata display or data recordingfeatures needed to evaluate the performance requirements ofthe TMD shall be specified by the user. If applicable, the usershall also specify the data items to be included in the display,the number of vehicle records to be displayed simultaneously,and whether the display
49、of selected records must occur withoutinterference with the continuous acquisition of data.6.10 Acceptance Test RequirementThe user shall specifythe acceptance test category, Type-approval or On-site Verifi-cation using the process illustrated in Fig. 1, and the testingschedule that will be utilized prior to final acceptance by theuser and final payment to the seller before the beginning of thetest. The acceptance test procedure may require the user toprovide traffic control as part of TMD installation. The user orthe users authorized represe
