Passage 1
Traffic lights are crucial tools for regulating traffic flow. They are not, however, perfect.
Drivers exchange the gridlock that would happen at unmanaged junctions for a pattern of stop-go movement that can still be frustrating, and which burns 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, whi
A.It is intended to keep track of traffic jams
B.It can show where all traffic lights are
C.It enables phones to share the information
D.It works as a brake that slows down the car