Lisbon is connected by rail and road to the interior of Portugal and to the rest of Europe. The 1.5-mile- (2.4-km-) long 25th of April Bridge, one of the longest suspension bridges in western Europe, has served as the main roadway into the city since it was built in the mid-1960s.
NHTSA estimates that 73% of light vehicles already voluntarily will have rear-view cameras by the final deadline of 2018 and that the cost per vehicle to equip the remainder will be $132 to $142 for a complete system, $43 to $45 to add the camera to a vehicle that already has an adequate display screen.
At the rear of the camera (just in front of the film or light sensor) is a shutter. The shutter is in the form of several curtains that expose the film/light sensor to a consistent amount of light across the entire film/sensor. The amount of time the shutter is open helps determine how much light will reach the sensor.