2019 高考英语二轮阅读理解专练（详解）&mdash;科普知识<br />Traffic lights are key tools for regulating traffic now.They are not, however, <br />perfect. Drivers exchange the traffic jams that would happen at unmanaged crossings <br />for a pattern of stopgo movement that can still be annoying, and which burns more <br />fuel than a smooth passage would.<br />Creating such a smooth passage means adjusting a vehicle&#039;s speed so that it <br />always arrives at the lights when they are green.That is theoretically possible, <br />but practically hard.Roadside signs wired to traffic lights can help get the message <br />across a couple hundred metres from a crossing, but such signs are expensive, and <br />are not widespread.Margaret Martonosi and Emmanouil Koukoumidis at Princeton <br />University, and LiShiuan Peh at the Massachusetts Institute of Technology, however, <br />have an idea that could make the process cheaper and more effective.Instead of a <br />hardwired network of signs, they propose to use mobilephone applications.<br />For a driver to benefit, he must load the team&#039;s software, named SignalGuru, <br />into his phone and then put it on a special thing attached to the inside of his car&#039;s <br />windscreen, with the camera lens (镜头) pointing forward.SignalGuru is designed to <br />detect traffic lights and track their status as red, yellow or green.It broadcasts <br />this information to other phones in the area that are fitted with the same software, <br />and&mdash;if there are enough of them, the phones thus each know the status of most of <br />the lights around town.Using this information, SignalGuru is able to calculate the <br />trafficlight schedule for the area and suggest the speed at which a driver should <br />travel in order to avoid red lights.<br />Tests in Cambridge, Massachusetts, where five drivers were asked to follow the <br />same route for three hours, and in Singapore, where eight drivers were asked to follow <br />one of two routes for 30 minutes, revealed that SignalGuru was capable of predicting <br />trafficlight activity with an accuracy of 98.2% and 96.3% respectively, in the two <br />cities.This was particularly impressive because in Cambridge the lights shifted, <br />roughly halfway through the test, from their unbusy schedule to their afternoon-<br />traffic schedule, while in Singapore lights are adaptive, using detectors fixed <br />under the road to determine how much traffic is present and thus when a signal should <br />change.In neither case was SignalGuru fooled.<br />Fuel consumption fell, too&mdash;by about 20%.SignalGuru thus reduces both annoyance <br />and fuel use, and makes going back and forth to work a slightly less horrible <br />experience.<br />1．Roadside signs wired to traffic lights are not the best way to create a smooth <br />passage because ________，<br />A．they are expensive and easily break<br />B．they are too costly and not widely used<br />C．they are complex and confusing to drivers<br />D．they are theoretically possible but practically useless<br />2．SignalGuru is an applicatio...