http://www.popularmechanics.com/cars/a9096/why-high-speed-police-chases-are-going-away-15532838/
Almost all U.S. law enforcement agencies have adopted a restrictive pursuit policy, according to the International Association of Chiefs of Police (IACP). Much to the dismay of TV executives, most cops will no longer conduct long chases that start when the officer tries to pull a motorist over for a broken taillight (though cops still chase suspected felons and other serious bad guys.) Before restrictive-pursuit policies, often the worst thing that officers found at the end of a chase was a suspended license, an ashtray full of seeds and stems, or empty beer cans in the pickup bed. Now, many law enforcement agencies have decided that it's not worth the danger when such chases could cause the death of the suspect, an officer, or an innocent.