【正文】 xceed allowed weights are usually marked with overweight load and must obtain a permit to use certain roads.Rules governing the maximum size and weight of vehicles differ from one . state to another. However, since the majority of hauling is done on the interstate system, the vast majority of trucks and trailers made in the . are built to the specifications of the Department of Transportation (DOT), which governs the use of the interstate system. The DOT has established these vehicle limits: 102inches wide, feet in height, and 80,000lbs gross weight. These limits can be exceeded as individual states have the right to issue temporary oversize and/or overweight permits.Trailer dimensions vary greatly, depending on the amount and type of cargo it was designed to haul. (See types of trailers under Construction, below.)Although dual wheels are most mon, use of two single, wider tires(known as super singles) on each axle is being popular, initially among bulk cargo carriers and other weightsensitive operators. With a growing desire to reduce greenhouse gas emissions the use of the super single tire is gaining popularity. The three advantages of this configuration are: (1) super singles reduce fuel consumption. Testing on an oval track (Canada 2009) showed 10% fuel savings when using super singles. The savings e from less energy wasted flexing tire side walls. Fewer tire side walls equates to less wasted energy。 (2) the lighter tire weight allows a truck to be loaded with more freight。 (3) the single wheel covers less of the brake unit, which allows faster cooling and reduces brake fade.Perhaps the largest disadvantage is when one tire bees deflated or destroyed, the remaining tire (in a dual axle configuration) may not prevent the load from causing damage to rim of the deflated tire before the vehicle is stopped. In a dual tire configuration the rim of the deflated tire is prevented from touching the roadway by the fully inflated tire mounted beside it. (Note: it is illegal to drive a mercial vehicle with a deflated or destroyed tire).Another innovation rapidly growing in popularity is the skirted trailer. The area between the road and the bottom of the trailer frame was previously left open, however the air moving under the trailer is a source of aerodynamic drag. Also without the trailer skirt drivers of smaller cars may attempt to drive under the trailer, resulting in accidents. Oval track testing (Canada 2009) proved it is possible to improve fuel economy by 8%, depending on the design and installation configuration of the trailer skirt. The more pletely the airflow under the trailer is blocked the better the improvement in fuel economy.The United States also allows 2axle tractors to tow two 1axle (m) semitrailers known officially as STAA doubles and colloquially as doubles, a set, or a set of joints on all highways that are part of the National Network. The second trailer in a set of doubles uses a converter gear, also known as a congear or dolly. This apparatus supports the front half of the second trailer. Individual states may further allow longer vehicles (known as longer bination vehicles or LCVs, and may allow them to operate on roads other than those part of the National Network.附 錄（B）英文文獻(xiàn)翻譯半掛汽車一個半掛車的卡車,也稱為半,撞上,或者(在英國和愛爾蘭的卡車或關(guān)節(jié)卡車)表達(dá),通常是一種藝術(shù),表達(dá),車輛組成的一個拖曳引擎(拖拉機(jī)在美國、澳大利亞、原動機(jī)卡車在愛爾蘭和卡車在英國、加拿大、新西蘭)、半掛車(包括可能的額外的拖車)的運費。一個半掛車并不小道完全后面拖,但在某種程度上這是前進(jìn)的rearmost軸的單位,因此,一些拖分?jǐn)?shù)的重量是由拖車后橋(s)的原動力。該協(xié)定要求都是截然不同的半掛車牽引車設(shè)計從剛體汽車、拖車?！≡诒泵?牽引車通常有三軸,前軸有兩個輪子,每兩個后輪軸擁有一雙“dualies”輪胎。因此,最常見的配置有10輪牽引車,但是在某些情況下,雙輪子都換成了輪胎被稱為“超單打”(見下文),或widebase單打,減輕體重的牽引車。(約180磅的體重減少每軸當(dāng)使用超單打)。在這種情況下,牽引車將只有六個輪子。一個小型牽引車,有一個單一的驅(qū)動軸(6個車)常被用來把短拖車在城市環(huán)境緊密,如市中心地區(qū)60英尺高的鉆機(jī)很難操作。沉睡的日子出租車(卡車)而通常不需要單軸,但每天用卡車和出租車者均采用它們。貨物拖車通常有兩個“串聯(lián)”軸在尾部,每一種都有一個雙重輪子或8輪的。許多拖車配有可和第五輪三輪車,可以調(diào)整重量在每個軸呆在法律范圍之內(nèi)。雖然總和的權(quán)重的牽引車、拖車(重量)通常被限制在一定金額,有些道路標(biāo)志著一個不同的總量限制以防止損壞。貨物重量超過允許超重負(fù)荷,通常標(biāo)明必須獲得許可使用特定的道路。規(guī)章制度的最大不同大小和不同重量的車輛從美國國家到另一個國家。然而,因為絕大多數(shù)的拖在州際公路系統(tǒng),絕大多數(shù)的卡車和拖車在美國正在建造的規(guī)格交通部(DOT),它支配使用的州際公路系統(tǒng)。建立了這些車輛點限制:102英寸寬、,8萬磅的重量。這些限制可以超越作為各州有權(quán)在臨時的特大型和/或過重的許可。拖車尺寸變化很大,根據(jù)貨物的數(shù)量和類型的設(shè)計。(見類型的拖車正在建設(shè),下方。)盡管雙輪子是最常見的,使用的兩種單一、寬輪胎(被稱為“超單打”)在每一個軸正變得流行起來,開始在散貨載體和其他weightsensitive運營商。不斷增長的欲望,減少溫室氣體的排放所使用的超單是逐漸普及。這三個該結(jié)構(gòu)的優(yōu)點是:(1)超級單打減少燃料消耗。在橢圓形賽道測試(加拿大)顯示10%的燃料節(jié)省2009年當(dāng)使用超單打。節(jié)省能源浪費伸縮來減少輪胎側(cè)墻。胎側(cè)墻等同于少少浪費能源。(2)較輕的重量,讓一輛卡車輪胎,滿載更多的貨物。(3)單輪制動單元覆蓋的,它允許更快的冷卻和降低剎車褪色。也許最大的缺點就是當(dāng)一個輪胎變成氣或者滅失,剩下的輪胎(雙軸配置,可防止負(fù)荷造成傷害之前的氣胎邊緣的車輛停住了。在雙胎配置的氣胎而感人的道路被完全充氣輪胎騎在它的旁邊。(注:這是非法的駕駛汽車輪胎的氣或破壞和)。另一個創(chuàng)新的快速增長的流行是環(huán)繞懸垂型。這個地區(qū)的道路和底部之間的幀之前是敞開的,但在空中移動拖車是一個來源的空氣阻力。也沒有懸垂裙子的小排量汽車司機(jī)可能試圖開車在拖車,導(dǎo)致交通事故的發(fā)生。橢圓形賽道測試(加拿大)證明它是可能的,到2009年,提高燃油經(jīng)濟(jì)性有8%,根據(jù)設(shè)計和安裝配置的裙子。更完全的氣流在拖車是堵住了更好的燃油經(jīng)濟(jì)性方面取得的進(jìn)步。美國也允許2axle拖拉機(jī)拖兩1axle (87米)半掛車已知的正式建立雙打和一般為雙打、一套,或一組節(jié)理所有高速公路上的一部分,是全國網(wǎng)絡(luò)。第二個拖車在一套雙打采用變頻器齒輪,也稱為congear或多利。該儀器支持的前半部第二懸垂型。個別的國家可能會進(jìn)一步使不再車輛(被稱為“長”或LCVs組合工具,可以讓他們在公路以外的其他國家的網(wǎng)絡(luò)。