the thin ribbons of gray macadam

The ambush of Barrow and Parker proved to be the beginning of the end
of the "public enemy era" of the 1930s. New federal statutes that made
bank robbery and kidnapping federal offenses, the growing coordination
of local jurisdictions by the FBI—plus the installation of two-way
radios in police cars—combined to make the free-ranging outlaw bandit
lifestyle much more difficult in the summer of 1934 than it had been
just a few months before. Two months after Gibsland, John Dillinger
was ambushed and killed on the street in Chicago; three months after
that, Charles Arthur "Pretty Boy" Floyd took 14 FBI bullets in the
back in Ohio; and one month after that, Lester "Baby Face Nelson"
Gillis shot it out, and lost, in Illinois. Thereafter, the Public
Enemies would no longer operate on thin ribbons of gray macadam across
America, but only on silver screens throughout the world. --
http://en.wikipedia.org/wiki/Bonnie_and_Clyde