This little-known rule causes speed limits to go up in Texas

(NEXSTAR) – When the signs changed on State Highway 130 in 2012, and the posted speed limit rose to 85 mph, the 90-mile stretch of road officially earned the title of fastest highway in the nation. But Highway 130 is far from the only Texas route where cars have been going faster over time — and are doing so legally.
Texas, like many other states around the country, sets speed limits on state roadways using the "85% rule." Basically, the Department of Transportation comes o