§571.121 49 CFR Ch. V (10–1–04 Edition) - ComplianceOnline
§ 571.12149 CFR Ch. V (10–1–04 Edition)tires as suitable for use with those tires, inaccordance with S5.1 of § 571.119, except thatvehicles may be equipped with a non-pneumatic spare tire assembly that meets the requirements of § 571.129, New non-pneumatictires for passenger cars, and S8 of this standard. Vehicles equipped with such an assembly shall meet the requirements of S5.3.3, S7,and S9 of this standard.S5.1.2 Except in the case of a vehiclewhich has a speed attainable in 3.2 kilometers of 80 kilometers per hour or less, thesum of the maximum load ratings of thetires fitted to an axle shall be not less thanthe gross axle weight rating (GAWR) of theaxle system as specified on the vehicle’s certification label required by 49 CFR part 567.Except in the case of a vehicle which has aspeed attainable in 2 miles of 50 mph or less,the sum of the maximum load ratings of thetires fitted to an axle shall be not less thanthe gross axle weight rating (GAWR) of theaxle system as specified on the vehicle’s certification label required by 49 CFR part 567.If the certification label shows more thanone GAWR for the axle system, the sum shallbe not less than the GAWR corresponding tothe size designation of the tires fitted to theaxle. If the size designation of the tires fittedto the axle does not appear on the certification label, the sum shall be not less thanthe lowest GAWR appearing on the label.When a tire subject to FMVSS No. 109 or 139is installed on a multipurpose passenger vehicle, truck, bus, or trailer, the tire’s loadrating shall be reduced by dividing by 1.10before calculating the sum (i.e., the sum ofthe load ratings of the tires on each axle,when the tires’ load carrying capacity at therecommended tire cold inflation pressure isreduced by dividing by 1.10, must be appropriate for the GAWR).*****S5.3 Each vehicle shall show the information specified in S5.3.1 and S5.3.2 and, in thecase of a vehicle equipped with a non-pneumatic spare tire, the information specified inS5.3.3, in the English language, lettered inblock capitals and numerals not less than 2.4millimeters high and in the format set forthfollowing this paragraph. This informationshall appear either—(a) After each GAWR listed on the certification label required by § 567.4 or § 567.5 ofthis chapter; or at the option of the manufacturer,(b) On the tire information label affixed tothe vehicle in the manner, location, andform described in § 567.4 (b) through (f) of thischapter as appropriate of each GVWR–GAWRcombination listed on the certification label.*****§ 571.121 Standard No. 121; Air brakesystems.S1. Scope. This standard establishesperformance and equipment requirements for braking systems on vehiclesequipped with air brake systems.S2. Purpose. The purpose of thisstandard is to insure safe braking performance under normal and emergencyconditions.S3. Application. This standard appliesto trucks, buses, and trailers equippedwith air brake systems. However, itdoes not apply to:(a) Any trailer that has a width ofmore than 102.36 inches with extendable equipment in the fully retractedposition and is equipped with two shorttrack axles in a line across the width ofthe trailer.(b) Any vehicle equipped with an axlethat has a gross axle weight rating(GAWR) of 29,000 pounds or more;(c) Any truck or bus that has a speedattainable in 2 miles of not more than33 mph;(d) Any truck that has a speed attainable in 2 miles of not more than 45mph, an unloaded vehicle weight thatis not less than 95 percent of its grossvehicle weight rating (GVWR), and nocapacity to carry occupants other thanthe driver and operating crew;(e) Any trailer that has a GVWR ofmore than 120,000 pounds and whosebody conforms to that described in thedefinition of heavy hauler trailer setforth in S4;(f) Any trailer that has an unloadedvehicle weight which is not less than 95percent of its GVWR; and(g) Any load divider dolly.S4. Definitions.Agricultural commodity trailer means atrailer that is designed to transportbulk agricultural commodities in offroad harvesting sites and to a processing plant or storage location, as evidenced by skeletal construction thataccommodates harvest containers, amaximum length of 28 feet, and an arrangement of air control lines and reservoirs that minimizes damage in fieldoperations.Air brake system means a system thatuses air as a medium for transmittingpressure or force from the driver control to the service brake, including anair-over-hydraulic brake subsystem,388VerDate Aug 04 200406:57 Oct 20, 2004Jkt 203209PO 00000Frm 00388Fmt 8010Sfmt 8010Y:\SGML\203209T.XXX203209T
Nat’l Highway Traffic Safety Admin., DOTbut does not include a system that usescompressed air or vacuum only to assist the driver in applying muscularforce to hydraulic or mechanical components.Air-over-hydraulicbrakesubsystemmeans a subsystem of the air brakesystem that uses compressed air totransmit a force from the driver control to a hydraulic brake system to actuate the service brakes.Antilock brake system or ABS means aportion of a service brake system thatautomatically controls the degree ofrotational wheel slip during brakingby:(1) Sensing the rate of angular rotation of the wheels;(2) Transmitting signals regardingthe rate of wheel angular rotation toone or more controlling devices whichinterpret those signals and generate responsive controlling output signals;and(3) Transmitting those controllingsignals to one or more modulatorswhich adjust brake actuating forces inresponse to those signals.Auto transporter means a truck and atrailer designed for use in combinationto transport motor vehicles, in thatthe towing vehicle is designed to carrycargo at a location other than the fifthwheel and to load this cargo only bymeans of the towed vehicle.Common diaphragm means a singlebrake chamber diaphragm which is acomponent of the parking, emergency,and service brake systems.Container chassis trailer means asemitrailer of skeleton constructionlimited to a bottom frame, one or moreaxles, specially built and fitted withlocking devices for the transport ofintermodal shipping containers, so thatwhen the chassis and container are assembled, the units serve the same function as an over the road trailer.Directly controlled wheel means awheel for which the degree of rotational wheel slip is sensed, either atthat wheel or on the axle shaft for thatwheel and corresponding signals aretransmitted to one or more modulatorsthat adjust the brake actuating forcesat that wheel. Each modulator mayalso adjust the brake actuating forcesat other wheels that are on the same§ 571.121axle or in the same axle set in responseto the same signal or signals.Effective projected luminous lens areameans that area of the projection on aplane perpendicular to the lamp axis ofthat portion of the light-emitting surface that directs light to the photometric test pattern, and does not include mounting hole bosses, reflex reflector area, beads or rims that mayglow or produce small areas of increased intensity as a result of uncontrolled light from small areas (1 2 degree radius around the test point).Full-treadle brake application means abrake application in which the treadlevalve pressure in any of the valve’soutput circuits reaches 85 pounds persquare inch (psi) within 0.2 secondsafter the application is initiated, or inwhich maximum treadle travel isachieved within 0.2 seconds after theapplication is initiated.Heavy hauler trailer means a trailerwhich has one or more of the followingcharacteristics, but which is not a container chassis trailer:(1) Its brake lines are designed toadapt to separation or extension of thevehicle frame; or(2) Its body consists only of a platform whose primary cargo-carryingsurface is not more than 40 inchesabove the ground in an unloaded condition, except that it may include sidesthat are designed to be easily removable and a permanent ‘‘front end structure’’ as that term is used in § 393.106 ofthis title.Independently controlled wheel meansa directly controlled wheel for whichthe modulator does not adjust thebrake actuating forces at any otherwheel on the same axle.Indirectly controlled wheel means awheel at which the degree of rotationalwheel slip is not sensed, but at whichthe modulator of an antilock brakingsystem adjusts its brake actuatingforces in response to signals from oneor more sensed wheel(s).Initial brake temperature means theaverage temperature of the servicebrakes on the hottest axle of the vehicle 0.2 mile before any brake application in the case of road tests, or 18 seconds before any brake application inthe case of dynamometer testing.389VerDate Aug 04 200406:57 Oct 20, 2004Jkt 203209PO 00000Frm 00389Fmt 8010Sfmt 8010Y:\SGML\203209T.XXX203209T
§ 571.12149 CFR Ch. V (10–1–04 Edition)Intermodal shipping container means areusable, transportable enclosure thatis especially designed with integrallocking devices for securing the container to the trailer to facilitate theefficient and bulk shipping and transferof goods by, or between various modesof transport, such as highway, rail, seaand air.Load divider dolly means a trailercomposed of a trailer chassis and oneor more axles, with no solid bed, body,or container attached, and which is designed exclusively to support a portionof the load on a trailer or truck excluded from all the requirements ofthis standard.Maximum drive-through speed meansthe highest possible constant speed atwhich the vehicle can be driventhrough 200 feet of a 500-foot radiuscurve arc without leaving the 12-footlane.Maximum treadle travel means the distance that the treadle moves from itsposition when no force is applied to itsposition when the treadle reaches a fullstop.Peak friction coefficient or PFC meansthe ratio of the maximum value ofbraking test wheel longitudinal forceto the simultaneous vertical force occurring prior to wheel lockup, as thebraking torque is progressively increased.Pulpwood trailer means a trailer thatis designed exclusively for harvestinglogs or pulpwood and constructed witha skeletal frame with no means for attachment of a solid bed, body, or container, and with an arrangement of aircontrol lines and reservoirs designed tominimize damage in off-road operations.Tandem axle means a group or set oftwo or more axles placed in a close arrangement, one behind the other, withthe centerlines of adjacent axles notmore than 72 inches apart.Straddle trailer means a trailer that isdesigned to transport bulk agriculturalcommodities from the harvesting location as evidenced by a framework thatis driven over the cargo and liftingarms that suspend the cargo for transit.Wheel lockup means 100 percent wheelslip.S5. Requirements. Each vehicle shallmeet the following requirements underthe conditions specified in S6.S5.1 Required equipment for trucksand buses. Each truck and bus shallhave the following equipment:S5.1.1 Air compressor. An air compressor of sufficient capacity to increase air pressure in the supply andservice reservoirs from 85 psi to 100 psiwhen the engine is operating at the vehicle manufacturer’s maximum recommended r.p.m. within a time, in seconds, determined by the quotient (Actual reservoir capacity 25)/Requiredreservoir capacity.S5.1.1.1 Air compressor cut-in pressure. The air compressor governor cutin pressure for each bus shall be 85p.s.i. or greater. The air compressorgovernor cut-in pressure for each truckshall be 100 p.s.i. or greater.S5.1.2 Reservoirs. One or more service reservoir systems, from which air isdelivered to the brake chambers, andeither an automatic condensate drainvalve for each service reservoir or asupply reservoir between the servicereservoir system and the source of airpressure.S5.1.2.1 The combined volume of allservice reservoirs and supply reservoirsshall be at least 12 times the combinedvolume of all service brake chambers.For each brake chamber type having afull stroke at least as great as the firstnumber in Column 1 of Table V, but nomore than the second number in Column 1 of Table V, the volume of eachbrake chamber for purposes of calculating the required combined serviceand supply reservoir volume shall beeither that specified in Column 2 ofTable V or the actual volume of thebrake chamber at maximum travel ofthe brake piston or pushrod, whicheveris lower. The volume of a brake chamber not listed in Table V is the volumeof the brake chamber at maximumtravel of the brake piston or pushrod.The reservoirs of the truck portion ofan auto transporter need not meet thisrequirement for reservoir volume.S5.1.2.2 Each reservoir shall be capable of withstanding an internal hydrostatic pressure of five times the compressor cutout pressure or 500 psi,whichever is greater, for 10 minutes.390VerDate Aug 04 200406:57 Oct 20, 2004Jkt 203209PO 00000Frm 00390Fmt 8010Sfmt 8010Y:\SGML\203209T.XXX203209T
Nat’l Highway Traffic Safety Admin., DOTS5.1.2.3 Each service reservoir system shall be protected against loss ofair pressure due to failure or leakage inthe system between the service reservoir and the source of air pressure,by check valves or equivalent deviceswhose proper functioning can bechecked without disconnecting any airline or fitting.S5.1.2.4 Each reservoir shall have acondensate drain valve that can bemanually operated.S5.1.3 Towing vehicle protection system. If the vehicle is intended to towanother vehicle equipped with airbrakes, a system to protect the airpressure in the towing vehicle from theeffects of a loss of air pressure in thetowed vehicle.S5.1.4 Pressure gauge. A pressuregauge in each service brake system,readily visible to a person seated in thenormal driving position, that indicatesthe service reservoir system air pressure. The accuracy of the gauge shallbe within plus or minus 7 percent ofthe compressor cut-out pressure.S5.1.5 Warning signal. A signal,other than a pressure gauge, that givesa continuous warning to a person inthe normal driving position when theignition is in the ‘‘on’’ (‘‘run’’) positionand the air pressure in the service reservoir system is below 60 psi. The signal shall be either visible within thedriver’s forward field of view, or bothaudible and visible.S5.1.6 Antilock brake system.S5.1.6.1(a) Each single-unit vehiclemanufactured on or after March 1, 1998,shall be equipped with an antilockbrake system that directly controls thewheels of at least one front axle andthe wheels of at least one rear axle ofthe vehicle. Wheels on other axles ofthe vehicle may be indirectly controlled by the antilock brake system.(b) Each truck tractor manufacturedon or after March 1, 1997, shall beequipped with an antilock brake system that directly controls the wheelsof at least one front axle and thewheels of at least one rear axle of thevehicle, with the wheels of at least oneaxle being independently controlled.Wheels on other axles of the vehiclemay be indirectly controlled by theantilock brake system. A truck tractor§ 571.121shall have no more than three wheelscontrolled by one modulator.S5.1.6.2 Antilock malfunction signaland circuit.(a) Each truck tractor manufacturedon or after March 1, 1997, and each single unit vehicle manufactured on orafter March 1, 1998, shall be equippedwith an indicator lamp, mounted infront of and in clear view of the driver,which is activated whenever there is amalfunction that affects the generation or transmission of response orcontrolsignalsinthevehicle’santilock brake system. The indicatorlamp shall remain activated as long assuch a malfunction exists, wheneverthe ignition (start) switch is in the ‘‘on’’(‘‘run’’) position, whether or not the engine is running. Each message aboutthe existence of such a malfunctionshall be stored in the antilock brakesystem after the ignition switch isturned to the ‘‘off’’ position and automatically reactivated when the ignition switch is again turned to the ‘‘on’’(‘‘run’’) position. The indicator lampshall also be activated as a check oflamp function whenever the ignition isturned to the ‘‘on’’ (‘‘run’’) position. Theindicator lamp shall be deactivated atthe end of the check of lamp functionunless there is a malfunction or a message about a malfunction that existedwhen the key switch was last turned tothe ‘‘off’’ position.(b) Each truck tractor manufacturedon or after March 1, 2001, and each single unit vehicle manufactured on orafter March 1, 2001, that is equipped totow another air-braked vehicle, shallbe equipped with an electrical circuitthat is capable of transmitting a malfunction signal from the antilockbrake system(s) on one or more towedvehicle(s) (e.g., trailer(s) and dolly(ies))to the trailer ABS malfunction lamp inthe cab of the towing vehicle, and shallhave the means for connection of thiselectrical circuit to the towed vehicle.Each such truck tractor and singleunit vehicle shall also be equipped withan indicator lamp, separate from thelamp required in S5.1.6.2(a), mounted infront of and in clear view of the driver,which is activated whenever the malfunction signal circuit described abovereceives a signal indicating an ABS391VerDate Aug 04 200406:57 Oct 20, 2004Jkt 203209PO 00000Frm 00391Fmt 8010Sfmt 8010Y:\SGML\203209T.XXX203209T
§ 571.12149 CFR Ch. V (10–1–04 Edition)malfunction on one or more towed vehicle(s). The indicator lamp shall remain activated as long as an ABS malfunction signal from one or more towedvehicle(s) is present, whenever the ignition (start) switch is in the ‘‘on’’(‘‘run’’) position, whether or not the engine is running. The indicator lampshall also be activated as a check oflamp function whenever the ignition isturned to the ‘‘on’’ (‘‘run’’) position. Theindicator lamp shall be deactivated atthe end of the check of lamp functionunless a trailer ABS malfunction signal is present.(c) [Reserved]S5.1.6.3 Antilock power circuit fortowed vehicles. Each truck tractor manufactured on or after March 1, 1997, andeach single unit vehicle manufacturedon or after March 1, 1998, that isequipped to tow another air-braked vehicle shall be equipped with one ormore electrical circuits that providecontinuous power to the antilock system on the towed vehicle or vehicleswhenever the ignition (start) switch isin the ‘‘on’’ (‘‘run’’) position. Such a circuit shall be adequate to enable theantilock system on each towed vehicleto be fully operable.S5.1.7 Service brake stop lamp switch.A switch that lights the stop lampswhen the service brake control is statically depressed to a point that produces a pressure of 6 psi or less in theservice brake chambers.S5.1.8 Brake distribution and automatic adjustment. Each vehicle shall beequipped with a service brake systemacting on all wheels.(a) Brake adjuster. Wear of the servicebrakes shall be compensated for bymeans of a system of automatic adjustment. When inspected pursuant to S5.9,the adjustment of the service brakesshall be within the limits recommended by the vehicle manufacturer.(b) Brake indicator. For each brakeequipped with an external automaticadjustment mechanism and having anexposed pushrod, the condition of service brake under-adjustment shall bedisplayed by a brake adjustment indicator that is discernible when viewedwith 20/40 vision from a location adjacent to or underneath the vehicle,when inspected pursuant to S5.9.S5.2 Required equipment for trailers.Each trailer shall have the followingequipment:S5.2.1 Reservoirs. One or more reservoirs to which the air is deliveredfrom the towing vehicle.S5.2.1.1 The total volume of eachservice reservoir shall be at least eighttimes the combined volume of all service brake chambers serviced by thatreservoir. For each brake chamber typehaving a full stroke at least as great asthe first number in Column 1 of TableV, but no more than the second numberin column 1, the volume of each brakechamber for purposes of calculating therequired total service reservoir volumeshall be either the number specified inColumn 2 of Table V or the actual volume of the brake chamber at maximumtravel of the brake piston or pushrod,whichever is lower. The volume of abrake chamber not listed in Table V isthe volume of the brake chamber atmaximum travel of the brake piston orpushrod. The reservoirs on a heavyhauler trailer and the trailer portion ofan auto transporter need not meet thisrequirement for reservoir volume.S5.2.1.2 Each reservoir shall be capable of withstanding an internal hydrostatic pressure of 500 psi for 10 minutes.S5.2.1.3 Each reservoir shall have acondensate drain valve that can bemanually operated.S5.2.1.4 Each service reservoir shallbe protected against loss of air pressure due to failure or leakage in thesystem between the service reservoirand its source of air pressure by checkvalves or equivalent devices.S5.2.2 Brake distribution and automatic adjustment. Each vehicle shall beequipped with a service brake systemacting on all wheels.(a) Brake adjuster. Wear of the servicebrakes shall be compensated for bymeans of a system of automatic adjustment. When inspected pursuant to S5.9,the adjustment of the service brakesshall be within the limits recommended by the vehicle manufacturer.(b) Brake indicator. For each brakeequipped with an external automaticadjustment mechanism and having anexposed pushrod, the condition of service brake under-adjustment shall be392VerDate Aug 04 200406:57 Oct 20, 2004Jkt 203209PO 00000Frm 00392Fmt 8010Sfmt 8010Y:\SGML\203209T.XXX203209T
Nat’l Highway Traffic Safety Admin., DOTdisplayed by a brake adjustment indicator in a manner that is discerniblewhen viewed with 20/40 vision from alocation adjacent to or underneath thevehicle, when inspected pursuant toS5.9.S5.2.3 Antilock brake system.S5.2.3.1(a) Each semitrailer (including a trailer converter dolly) manufactured on or after March 1, 1998, shall beequipped with an antilock brake system that directly controls the wheelsof at least one axle of the vehicle.Wheels on other axles of the vehiclemay be indirectly controlled by theantilock brake system.(b) Each full trailer manufactured onor after March 1, 1998, shall be equippedwith an antilock brake system that directly controls the wheels of at leastone front axle of the vehicle and atleast one rear axle of the vehicle.Wheels on other axles of the vehiclemay be indirectly controlled by theantilock brake system.S5.2.3.2 Antilock malfunction signal.Each trailer (including a trailer converter dolly) manufactured on or afterMarch 1, 2001, that is equipped with anantilockbrakesystemshallbeequipped with an electrical circuit thatis capable of signaling a malfunction inthe trailer’s antilock brake system,and shall have the means for connection of this antilock brake system malfunction signal circuit to the towingvehicle. The electrical circuit need notbe separate or dedicated exclusively tothis malfunction signaling function.The signal shall be present wheneverthere is a malfunction that affects thegeneration or transmission of responseor control signals in the trailer’santilock brake system. The signal shallremain present as long as the malfunction exists, whenever power is suppliedto the antilock brake system. Eachmessage about the existence of such amalfunction shall be stored in theantilock brake system whenever poweris no longer supplied to the system,and the malfunction signal shall beautomatically reactivated wheneverpower is again supplied to the trailer’santilock brake system. In addition,each trailer manufactured on or afterMarch 1, 2001, that is designed to towother air-brake equipped trailers shallbe capable of transmitting a malfunc-§ 571.121tion signal from the antilock brakesystems of additional trailers it towsto the vehicle towing it.S5.2.3.3 Antilock malfunction indicator.(a) In addition to the requirements ofS5.2.3.2, each trailer and trailer converter dolly manufactured on or afterMarch 1, 1998, and before March 1, 2009,shall be equipped with an externalantilock malfunction indicator lampthat meets the requirements of S5.2.3.3(b) through (d).(b)(1) The lamp shall be designed toconform to the performance requirements of Society of Automotive Engineers (SAE) Recommended PracticeJ592 JUN92, or J592e, July 1972, Clearance, Side Marker, and IdentificationLamps, for combination, clearance, andside marker lamps, which are markedwith a ‘‘PC’’ or ‘‘P2’’ on the lens or housing, in accordance with SAE J759 Jan95, Lighting Identification Code. SAEJ592 June 92, SAE J592e July 1972, andSAE J759 January 1995, are incorporated by reference and thereby aremade part of this standard. The Director of the Federal Register approvedthe material incorporated by referencein accordance with 5 U.S.C. 552(a) and 1CFR part 51. Copies of the materialmay be inspected at NHTSA’s DocketSection, 400 Seventh Street, SW., room5109, Washington, DC, or at the National Archives and Records Administration (NARA). For information onthe availability of this material atNARA, call 202–741–6030, or go to: ederallregulations/ibrllocations.html.(2) The color of the lamp shall be yellow.(3) The letters ‘‘ABS’’ shall be permanently molded, stamped, or otherwisemarked or labeled in letters not lessthan 10 mm (0.4 inches) high on thelamp lens or its housing to identify thefunction of the lamp. Alternatively,the letters ‘‘ABS’’ may be painted onthe trailer body or dolly or a plaquewith the letters ‘‘ABS’’ may be affixedto the trailer body or converter dolly;the letters ‘‘ABS’’ shall be not less than25 mm (1 inch) high. A portion of one ofthe letters in the alternative identification shall be not more than 150 mm393VerDate Aug 04 200406:57 Oct 20, 2004Jkt 203209PO 00000Frm 00393Fmt 8010Sfmt 8010Y:\SGML\203209T.XXX203209T
§ 571.12149 CFR Ch. V (10–1–04 Edition)(5.9 inches) from the edge of the lamplens.(c) Location requirements. (1) Eachtrailer that is not a trailer converterdolly shall be equipped with a lampmounted on a permanent structure onthe left side of the trailer as viewedfrom the rear, no closer than 150 mm(5.9 inches), and no farther than 600mm (23.6 inches) from the red rear sidemarker lamp, when measured betweenthe closest edge of the effective projected luminous lens area of each lamp.(2) Each trailer converter dolly shallbe equipped with a lamp mounted on apermanent structure of the dolly sothat the lamp is not less than 375 mm(14.8 inches) above the road surfacewhen measured from the center of thelamp with the dolly at curb weight.When a person, standing 3 meters (9.8feet) from the lamp, views the lampfrom a perspective perpendicular to thevehicle’s centerline, no portion of thelamp shall be obscured by any structure on the dolly.(3) Each trailer that is not a trailerconverter dolly and on which the malfunction indicator lamp cannot beplaced within the location specified inS5.2.3.3(c)(1) shall be equipped with alamp mounted on a permanent structure on the left side of the trailer asviewed from the rear, near the red rearside marker lamp or on the front faceof the left rear fender of a trailerequipped with fenders.(d) The lamp shall be illuminatedwhenever power is supplied to theantilock brake system and there is amalfunction that affects the generation or transmission of response orcontrol signals in the trailer’s antilockbrake system. The lamp shall remainilluminated as long as such a malfunction exists and power is supplied to theantilock brake system. Each messageabout the existence of such a malfunction shall be stored in the antilockbrake system whenever power is nolonger supplied to the system. Thelamp shall be automatically reactivated when power is again supplied tothe trailer’s antilock brake system.The lamp shall also be activated as acheck of lamp function whenever poweris first supplied to the antilock brakesystem and the vehicle is stationary.The lamp shall be deactivated at theend of the check of lamp function, unless there is a malfunction or a message about a malfunction that existedwhen power was last supplied to theantilock brake system.S5.3 Service brakes—road tests. Theservice brake system on each trucktractor shall, under the conditions ofS6, meet the requirements of S5.3.1,S5.3.3, S5.3.4, and S5.3.6, when testedwithout adjustments other than thosespecified in this standard. The servicebrake system on each bus and truck(other than a truck tractor shall) manufactured before July 1, 2005 and eachbus and truck (other than a truck tractor) manufactured in two or morestages shall, under the conditions ofS6, meet the requirements of S5.3.1,S5.3.3, and S5.3.4 when tested withoutadjustments other than those specifiedin this standard. The service brake system on each bus and truck (other thana truck tractor) manufactured on orafter July 1, 2005 and each bus andtruck (other than a truck tractor)manufactured in two or more stages onor after July 1, 2006 shall, under theconditions of S6, meet the requirements of S5.3.1, S5.3.3, S5.3.4, andS5.3.6, when tested without adjustments other than those specified inthis standard. The service brake system on each trailer shall, under theconditions of S6, meet the requirements of S5.3.3, S5.3.4, and S5.3.5 whentested without adjustments other thanthose specified in this standard. However, a heavy hauler trailer and thetruck and trailer portions of an autotransporter need not met the requirements of S5.3.S5.3.1 Stopping distance—trucks andbuses. When stopped six times for eachcombination of vehicle type, weight,and speed specified in S5.3.1.1, in thesequence specified in Table I, eachtruck tractor manufactured on or afterMarch 1, 1997, and each single unit vehicle manufactured on or after March1, 1998, shall stop at least once in notmore than the distance specified inTable II, measured from the point atwhich movement of the service brakecontrol begins, without any part of thevehicle leaving the roadway, and withwheel lockup permitted only as follows:394VerDate Aug 04 200406:57 Oct 20, 2004Jkt 203209PO 00000Frm 00394Fmt 8010Sfmt 8010Y:\SGML\203209T.XXX203209T
Nat’l Highway Traffic Safety Admin., DOT(a) At vehicle speeds above
§571.121 49 CFR Ch. V (10–1–04 Edition) tires as suitable for use with those tires, in accordance with S5.1 of §571.119, except that vehicles may be equipped with a non-pneu-matic spare tire assembly that meets the re-quirements of §571.129, New non-pneumatic tires for
Aug 05, 2021 · 1 49 CFR 575.104. 2 49 CFR 571.105, 571.121, 571.122, 571.126, 571.135, 571.136, 571.139, 571.500. 3 60 FR 6411, 6415–17 (Feb. 2, 1995). 4 Another reason for adopting the peak braking force related to the variability associated with determining skid number. Th
Code of Federal Regulations: 49 CFR §571.121 S5.1.8 applies to trucks, buses and truck tractors. 49 CFR §571.121 S5.2.2 while identical, applies to trailers. 49 CFR §571.121 (FMVSS 121) is applicable to manufacturers. 49 CFR 571.121 S5.1.8 Brake distribution and automatic adjustment. Each vehicle shall beFile Size: 541KB
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(19) 49 CFR §571.210 Seat belt assembly anchorages, as amended. (20) 49 CFR §571.121 Air brake systems, as amended. (21) 49 CFR §571.217 Bus emergency exits and window retention and release, as amended. (22) 49 CFR §571.220 School bus rollover protection, as amended. (23) 49 CFR §571
14 CFR Part 11 . 14 CFR Part 300 . 14 CFR Part 302 . 49 CFR Part 5 . 49 CFR Part 7 . 49 CFR Part 106 . 49 CFR Part 211 . 49 CFR Part 389 . 49 CFR Part 553 . 49 CFR Part 601 . RIN 2105-AE84 . Administrative Rulemaking, Guidance, and Enforcement Procedures . AGENCY: Office of the
571.105, Hydraulic and Electric Brake Systems 49 CFR 571.106 Brake Hoses, and 49 CFR 571.121, Air Brake Systems, as applicable. All buses shall have either a parking pawl in the transmission or a park brake interlock that requires the service brake to be applied to allow release of
37 CFR 1.55 has been filed in the instant patent application; and 3) any U.S. application-as-filed from which benefit is sought in the instant patent application. In accordance with 37 CFR 1.14(c), access may be provided to information concerning the date o f filing this Authorization.File Size: 803KBPage Count: 7Explore furtherApplication Data Sheet 37 CFR 1.76 (Paper Filed .www.formsworkflow.comForm-Fillable PDFs Available USPTOwww.uspto.govJustia :: Application Data Sheet (37 CFR 1.76) :: Official .forms.justia.comDECLARATION (37 CFR 1.63) FOR UTILITY OR DESIGN .www.uspto.gov37 CFR § 1.97 - Filing of information disclosure .www.law.cornell.eduRecommended to you b
AAMI HE75, Human factors engineering – Design of medical devices, Clause 9, Usability Testing, provides an excellent guide to the types of formative evaluations that are useful in early device UI development such as cognitive walkthroughs, heuristic evaluations, and walk-through-talk-through usability tests. Annex D of IEC 62366 also provides descriptions of these formative techniques .
