大學(xué)英語(yǔ)綜合教程第四冊(cè) 8

[00:00.00] Steve Shladover outlines the benefits to be gained from vehicles that could drive themselves [00:06.71]and discusses how this could be achieved. [00:10.61]INTELLIGENT VEHICLES by Steve Shladover [00:15.33]Even when cars were still young,futurists began thinking about vehicles that could drive themselves,without human help [00:24.79]Perhaps the best known of these conjectures was the General Motors Futurama,the hit of the1939 New York World's Fair [00:35.40]Now,at the start of the new century,it's worth taking a fresh look at this concept and asking [00:42.92]how automation mingt change transportation and the quality of our lives. [00:49.50]Consider some of the implications of cars that could drive themselves. [00:54.83]We might eliminate the more than ninety percent of traffic crashes [01:05.02]that are caused by human errors such as misjudgments and inattention. [01:10.92]We might reduce antisocial driving behavior such as road rage,thereby singnificantly reducing the stress of driving. [01:20.61]The entire population,including the young,the old,and the infirm, [01:26.70]might enjoy a higher level of mobility without requiring advanced driving skills. [01:33.91]The luxury of being chauffeured to your destination might be enjoyed by all,not just the wealthiest individuals. [01:42.82]Fuel consumption and pollution might be reduced by smoothing traffic flow [01:49.45]and running vehicles close enough to each other to benefit from aerodynamicdrafting. [01:56.48]Traffic-management decisions might be based on firm knowledge of vehicle responses to instructions, [02:03.79]rather than on guesses about the choices that drivers might make. [02:09.04]The capacity of a freeway lane might be doubled or tripled,making it possibe to accommodate growing demands for travel [02:18.00]without major new construction,or,equivalently,today's level of congestion mingt be reduced,enabling travelers to save time [02:28.43]Is it feasible? [02:30.96]This is now a realisitic prospect.With advances in technology [02:36.00]we can readily visualize your trip on an automated highway system. [02:41.67]Imagine leaving work at the end of the day and needing to drive only [02:47.05]as far as the nearest on-ramp to the local automated highway.At the onramp, [02:54.94]you press a button on your dashboard to select the off-ramp closest to your home and then relax [03:02.94]as your car's electronic systems,in cooperation with roadside electronics and similar systems on other cars, [03:11.76]guide your car smoothly,safely,and effortless toward your destiantion. [03:18.69]En route you save time by maintaining full speed even at rush-hour traffic volumes. [03:25.82]At the end of the off-ramp you resume normal control and drive the remaining distance of your home [03:32.90]better rested and less stressed than if you had driven the entire way. [03:38.93]Although many different technical developments are necessary to turn this image into reality,none requires exotic technologies [03:48.52]and all can be based on systems and components [03:52.99]that are already being actively developed in the international motor vehicle industry. [03:59.60]These could be viewed as replacements for the diverse functions that drivers perform every day:obserbving the road [04:08.01]observing the preceding vehicles,steering,accelerating,braking,and deciding when and where to change course. [04:16.78]Observing the road [04:19.66]Researches have developed a road-reference and sensing system [04:24.65]that makes it possible to determine accurately a vehicle's position and orientation relative to the lane's center. [04:33.19]Cheap permanent magnets are buried at four-foot intervals along the lane centerline [04:40.22]and detected by magnetometers mounted under the vehicle's bumpers.These meters prvide the information [04:49.23]used by the vehicle's control computer to determine its exact position of the vehicle. [04:56.57]Other researchers have used computer vision systems to observe the road.These are vulnerable to weather problems [05:05.37]and provide less accurate measurements,but they do not require special roadway installations. [05:12.66]other than well-maintained lane markings. [05:16.84]Observing preceding vehicles [05:20.39]The distances and closing rates to preceding vehicles can be measured by a radar or a laser rangefinder. [05:29.14]Both technologies have already been implemented in commercially available systems in Japan and Europe [05:36.82]The laser systems are currently less expensive, [05:40.27]but the radar systems are more effective at detecting dirty vehicles and operating in adverse weather conditions [05:49.41]As productins volumes increase and unit costs decrease, the radars are likely to find increasing favor. [05:57.77]Steering,accelerating and brading [06:02.03]The equivalents of these driver muscle functions are electromechanical devices installed in the automated vihicle [06:10.42]They receive electronic commands from the onboard control computer [06:14.91]and then apply the appropriate steering angle,throttle angle,and brakd [06:21.10]pressure by means of small electricmotorsEarly versions of these devices are alresdy being introduced int production vehicles [06:32.62]where they receive their commans directly from the driver's inputs to the steering whessl and pedals. [06:39.54]These decisions ate being made for reasons largely unrelated to automation. [06:44.66]Rather they are associated with reduced energy consumption, [06:49.99]simplification of vehicle design,enhanced ease of vehicle assembly, [06:55.32]improved ability to nadjust performance to match driver perferences, [07:00.96]and cost savings compatred to traditional direct mechanical comtrol devies. [07:07.68]Deciding when and where to change course [07:11.83]Computers in the vehicles and those at the roadside have different functions. [07:17.13]Roadside computer are computers are better suited for traffic management, [07:22.02]setting the target speed for each segment and lane of roadway, [07:26.09]and allocating vehicles to different lanes of a multilane automated facility. [07:32.18]The aim is to maintain balanced flow among the lanes and to avvoed obstacles or incidents tha might block alane. [07:40.70]The vihicle's onboard computers are better suited to handling decisions about exactly [07:47.72]when and where to change lanes to avoed inerference with other vehicles. [07:54.23]Remaining challenges [07:57.15]There remain a number of difficulties t be over come.These are mainly technical, [08:03.32]but there are in addition a number of nontechnical challenges that need to be addressed. [08:09.87]These involve issues of liability,costs,and perceptions. [08:15.28]Automated control of vehicles shifts liability for most crashes from the individual driver(and his or her insurance company [08:25.03]to the designer,developer,and vendor of the vehicle and roadway control systems.Provided the system is indeed safer [08:34.25]than today's driver-vehicle-highway system,overall exposure should be reduced .But its costs will be shifted [08:44.51]from automovile insurance premiums to the purchase or lease price of the automated vehicle [08:51.59]and toll for use of the automated highway facility. [08:56.27]All new techologies tend to be costly when they first become available in small quntities, [09:02.98]then their costs decline as production volumes increase and the technologies mature. [09:09.12]We should expect vehicle automation technologies to follow the same pattern. [09:14.92]They may initially be economically viable only for heavy vehicles(transit buses,commercial trucks)and highend passenger cars [09:24.64](2)However,it should not take long for the costs to become affordable to a wide range of vehicle owners and operators, [09:33.34]especially with many of the enabling technologies already being commercialized for volume production today. [09:41.59](3)The largest impediment to introduction of electronic chauffeuring may turn out be the general perception that [09:49.77]it's more difficult and expensive to implement than it really is. [09:54.55]If political and imdustrial decision maders perceive automated driving to be too futuristec, [10:01.91]they will not pay it the attention it deserves and will not invest their resources toward acceleerating its deployment. [10:10.48]The perception could thus become a self-fulfilling prophecy. [10:15.24]It is important to recognize that automated vehicles are already carrying millions of passengers every day. [10:23.07]Most major airports have automated people movers that transfer passengers among terminal buildings. [10:30.49]Urban transit lines in Paris,London,Vancouver, [10:35.98]Lyon,and Lille,among others,are operating with completely automated,driverless vehicles; [10:43.16]some have been doing so for more than a decade. [10:46.97]Modern commercial aircraft operate on autopilot for much of the time, [10:52.85]and they also land under automatic comtrol at suitably equipped airports on regular basis. [11:00.40](4)Given all of this experience in implemaenting safe automated transportation systemsm,it is not such a large leap [11:09.10]to develop road vehicles that can operate under automatic control.That should be a realistic goal for the next decade. [11:18.14]The transportation system will thus gain substantial benefits from the revolution in information techonlogy. [11:26.55]outline at the start of implication thereby [11:30.99]概述 在……開(kāi)始時(shí) 暗示 從而 [11:35.43]feasible realistic in cooperation with en route [11:40.77]有理的 實(shí)際的 與……合作 在途中 [11:46.12]component civerse permanent implement [11:51.17]部件 多種多樣的 永久的 實(shí)施 [11:56.23]equlvalent appropriate by means of assembly [12:01.45]相等物 適當(dāng)?shù)? 依靠 組裝 [12:11.35]暴露 長(zhǎng)成 引進(jìn) 認(rèn)為

00:00

00:00

MP3下載 文本下載