OASDI stands for old age, survivor and disability insurance, which is more commonly referred to as Social Security. To pay for these programs, the federal government imposes a tax on earned income that must be withheld by your employer.
According to the December 1985 issue of Popular Mechanics, the Protex Safety Signal Company introduced flashing turn signals in 1920. The first modern turn signal, though, can be attributed to Edgar A. Walz, Jr. who, in 1925, secured a patent for one and tried to market it to major car manufacturers. They just weren't interested, and the patent expired fourteen years later. Meanwhile drivers and inventors kept working on other solutions.
The first traffic light system to use red and green lights were patented by William Ghiglieri of San Francisco, California in 1917 (patented no 1,224,632).n 1868, British railroad signal engineer J P Knight invented the first traffic light, a lantern with red and green signals. It was installed at the intersection of George and Bridge Streets in front of the the British House of Commons to control the flow of horse buggies and pedestrians.