????汽車即將發生碰撞時，汽車安全系統就能立刻察覺，同時啟動剎車系統，收緊安全帶，以減輕對乘客的傷害。現在，這類系統正升級換代，未來有望完全防止某些碰撞。

????2013款雷克薩斯（Lexus）LS460是豐田汽車（Toyota）豪華品牌的旗艦。它將于今年11月登陸美國市場，屆時可選裝“高級預防撞系統”（advanced pre-collision system）。當時速低于29英里時，這套系統會用雷達和光學傳感器判斷車輛是否會與前方的行人或物體相撞。如果司機分神、注意力不集中或受傷，它會取而代之，在碰撞發生之前迫使汽車停下，可能特別有助于避免造成行人傷亡。

????未來某一天，豐田的這一安全裝置會安裝在絕大多數車輛上。它標志著不斷發展的自動駕駛技術邁出了新的步伐。很多人相信，這一技術進步必將在不遠的將來催生出無人駕駛汽車。市場研究公司HIS的汽車行業分析師呂蓓卡?林德蘭稱：“這類系統表明，我們在無人駕駛汽車的發展上又取得了更大的進步。十年內我們就能看到首輛無人駕駛汽車的誕生。現在人們還不太能相信這一點。但是當年一樣沒人相信馬會被汽車取代。”

????通用汽車（General Motors）、福特汽車（Ford Motor）、大眾汽車（Volkswagen），還有絕大多數汽車廠商和供應商都在開發無人駕駛或所謂的自動駕駛所需的數字與機械系統。大眾公司（VW）的奧迪品牌（Audi）已暗示，兩年內，它就將在下一代A8旗艦車型上搭載一套系統，能讓駕駛者在公路上處于低速的停停走走狀態時開啟“自動巡航”（automatic pilot）功能。在這一模式下，汽車能隨著車流自動行駛、加速和剎車，同時避開周圍的車輛。

????在帕洛阿爾托市（Palo Alto）的東部，靠近谷歌公司（Google）總部的一處大型停車場內，豐田的工程師和技術專家為媒體搭建了一條測試車道，用來展示其新型自動駕駛系統（而谷歌早就以其首創的自動駕駛汽車名噪一時了）。我也在受邀之列，得以駕著一輛搭載這一系統的LS460原型車，向一個由布制成、上面畫著一輛車的障礙物駛去。

????當提速到約時速30英里后，我將車對準那個布質目標駛去。首先，儀表盤上出現了一個前方有障礙物的視覺警示標識。隨后，車里響起了報警聲。雖然有點緊張，但我還是踩著油門不放。車繼續加速，碰撞似乎不可避免就要發生了，這時，車突然奪過控制權，隨著一聲尖銳的剎車聲，車在距障礙物咫尺之遙的地方停了下來。

????坐在副駕駛座上陪同我的一位技術人員向我解釋道，這套系統剎車的力量大約是普通駕駛者踩踏的兩倍。另一套名為“駕駛者注意力監測系統”（Driver Attention Monitor System）的系統則通過攝像頭觀察駕駛者的臉部表情，判斷駕駛者何時分神，司機較長時間沒看路面或是打盹的話，系統隨即會啟動閃光報警，同時發出警報聲。如果這些步驟都不奏效，自動駕駛系統就會自行剎車。

????盡管豐田在美國和日本的研發中心都在開發自動駕駛技術，但它對細節守口如瓶，不愿意透露完全自動化的汽車到底什么時候能夠投入測試。谷歌的無人駕駛汽車項目用一輛改裝的豐田普銳斯（Prius）已在公路上進行了超過10萬公里的測試，除了一次保險杠輕度彎曲外，沒有發生過任何事故。2011年，內華達州在全美率先修改了法律，允許無人駕駛汽車正式上路。谷歌則在今年3月獲得首個批準，讓一輛普銳斯上路。

????雷克薩斯的這款新LS還遠談不上能完全自動駕駛。但是，如果這套“高級預防撞系統” 能讓車主們避免事故，他們可能會開始體會到這種技術的效果。

????譯者：清遠

????Automotive safety systems that sense when a vehicle is about to crash and initiate braking and tighten seatbelts to mitigate injury are evolving into systems that can prevent some collisions entirely.

????The 2013 Lexus LS460, Toyota's (TM) luxury flagship, begins arriving in the U.S. in November with an "advanced pre-collision system" available as an option. When driving at speeds below 29 miles per hour, the system uses radar and optical sensors to determine if a car is likely to collide with a pedestrian or object ahead. The Toyota system can override a distracted, inattentive or impaired driver and bring the car to a stop prior to impact. It could prove especially helpful to preventing pedestrian injuries and deaths.

????Toyota's safety device, which one day could be equipped on many if not all vehicles, marks yet another step in the continuous automation of driving, a process that many believe leads inevitably to driverless vehicles in the not too distant future. "These kind of systems represent more progress toward driverless cars," said Rebecca Lindland, an industry analyst for HIS automotive. "We could see the first driverless cars in ten years. People have trouble believing it. No one could believe that horses would give way to automobiles."

????General Motors (GM), Ford Motor (F), Volkswagen and indeed most automakers and automotive suppliers are working on digital-mechanical systems that are integral to driverless or so-called autonomous driving. In two years VW's Audi luxury division has hinted it will offer a system on its next-generation A8 flagship that allows a driver in low-speed stop-and-go freeway traffic to put the vehicle on "automatic pilot." In this mode the vehicle automatically speeds, accelerates and stops with the flow of traffic and avoids other vehicles around it.

????Toyota engineers and technicians set up a test course for journalists in a large parking lot in east Palo Alto, near Google (GOOG) headquarters, to demonstrate its new system. (Google has made headlines with it driverless car initiative.) I was among those invited to drive a prototype of the LS460 equipped with the system toward a cloth barrier depicting a graphic of a car.

????After accelerating to about 30 miles per hour, I was aiming the LS460 toward the cloth target. First, a visual warning of an obstacle ahead appeared on the dashboard. Then, a chime sounded. Still, somewhat nervously, I kept my foot on the accelerator. A collision seemed inevitable when suddenly the car took control and braked us to a screeching halt just short of the barrier.

????A technician accompanying me in the front-passenger seat explained that the braking force of the system was roughly twice what a normal driver could accomplish by stamping on the pedal. Another system called the Driver Attention Monitor System trains cameras on the driver's face and determines when a driver has become distracted, taken eyes off the road too long or has fallen asleep -- and flashes a warning and sounds a chime. If those steps don't work, the system can apply the brakes.

????Though Toyota is working on autonomous driving at research and development centers in the U.S. and Japan the automaker has been reluctant to release details of when a fully autonomous car might be ready for testing. Google's driverless car project has tested a modified Toyota Prius on public roads for over 100,000 miles without an incident beyond a minor fender-bender. In 2011 Nevada became the first state in the U.S. to modify its traffic laws to permit operation of a driverless car. Google was issued the first permit for a Prius in March of this year.

????Lexus's new LS is far from ready to drive entirely on its own. But its owners may begin to understand how the technology could work if the Advanced Pre-Collision System saves them from an accident.