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  3. Traffic lights are crucial tools for regulating traffic flow. They are not, however, perfect. At unmanaged junctions, a pattern

Traffic lights are crucial tools for regulating traffic flow. They are not, however, perfect. At unmanaged junctions, a pattern

admin2013-11-18  46
问题     Traffic lights are crucial tools for regulating traffic flow. They are not, however, perfect. At unmanaged junctions, a pattern of stop-go movement can still be frustrating and burn more fuel than a smooth passage would. Creating such a smooth passage means adjusting a vehicle’s speed so that it always arrives at the lights when they are green. That is theoretically possible, but practically hard. Roadside signs wired to traffic lights may help, but they have not been widely deployed. Now scientists have an idea that could make the process cheaper and more effective. Instead of a hardwired network of signs, they propose to use mobile-phone apps.
    For a driver to benefit, he must load a special software, dubbed SignalGuru, into his phone and then mount it on a special bracket attached to the inside of his car’s windscreen, with the camera lens pointing forwards. SignalGuru is designed to detect traffic lights and track their status as red, amber or green. It broadcasts this information to other phones in the area that are fitted with the same software, and—if there are enough of them—the phones thus each know the status of most of the lights around town. Using this information, SignalGuru is able to calculate the traffic-light schedule for the region and suggest the speed at which a driver should travel in order to avoid running into red lights.
    Tests in Cambridge, Massachusetts, where five drivers were asked to follow the same route for three hours, and in Singapore, where eight drivers were asked to follow one of two routes for 30 minutes, revealed that SignalGuru was capable of predicting traffic-light activity with an accuracy of 98. 2% and 96. 3% respectively, in the two cities. This was particularly impressive because in Cambridge the lights shifted, roughly half-way through the test, from their off-peak schedule to their afternoon-traffic schedule, while in Singapore lights are adaptive, using detectors embedded(嵌入)under the road to determine how much traffic is around and thus when a signal should change. Fuel consumption fell, too—by about 20%. SignalGuru thus reduces both frustration and fuel use, and makes commuting a slightly less horrible experience.
What do drivers do if they want to pass unmanaged junctions smoothly?
选项 A、They must wait patiently until traffic lights turn green.
B、They need to help traffic police to regulate traffic flow.
C、They can drive through the red lights if nobody is around.
D、They have to adjust the speed in time for the green lights.
答案D
解析 事实细节题。根据定位句可知，在管理不善的交叉路口，驾驶过程让人懊恼，还会耗油，要想实现顺畅的行驶，就意味着要调节车速．让车辆在到达交通灯时总遇到绿灯便可。故正确答案为D)“他们必须及时调节速度以赶七绿灯”。
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