Police officers have a quiver-full of tools to track and catch highway speeders, ranging from the simplest and oldest methods to the most technologically advanced automated systems.
But a new survey from the Governors Highway Safety Association finds that 42 states allow drivers to exceed posted speed limits of up to 10 mph before pulling them over for speeding.
Association Chairman Jim Champagne says such speed "cushions" create an unsafe comfort level for high-speed -- and illegal -- antics on U.S. roadways.
He and other experts say U.S. police agencies already have most of the necessary tools to enforce speed limits.
By far, the most prevalent means of catching speeders hasn't changed much since the early days when U.S. drivers first began hitting the road: the infamous "speed trap."
But where 20th century highway patrol officers used to rely solely on their own eyes to determine a car's speed on the road, today's police have more sophisticated ways to tell if a motorist is going over the posted speed limit.
So-called radar guns are probably one of the well-known tools of the speed enforcement trade. Either mounted in police vehicles or held in an officer's hand, the "guns" emit pulses of invisible radio waves that can be "aimed" at suspected speeders. The gun determines the actual speed of the targeted car by timing how long it takes the radar waves to strike the car and bounce back.
The decreasing cost of electronics has made radar guns affordable and prevalent, and has made its successor -- the laser gun -- a viable alternative for many more police agencies.
By using invisible laser beams instead of radio waves, laser speed guns are quicker and less prone to interference from other sources of radio emissions.
Still, as many repeat offenders can attest to, there are ways of detecting -- and, arguably, defeating -- speed limit enforcement tools. Thousands of lead-footed drivers, for example, wouldn't dream of hitting the road without their radar and laser detectors to warn them of approaching hidden police speed traps.
While several states have laws against the use of such devices, to defeat speeders armed with detectors some highway agencies have gone back to a simpler form of clandestine speed detection: the nontechnical eyeball.
Simple markings on the roads, visible to police observers in helicopters or light airplanes, define a set distance -- say, a quarter of a mile. If a car takes 15 seconds to cover that distance, the vehicle is traveling roughly a mile per minute -- or 60 mph. Police officers in the air can then radio patrol cars to intercept any car that goes significantly faster.
While such tricks of the trade for highway "Smokies" are well tried and tested, experts note that such methods are labor intensive. And as more police officers are tasked with anti-terrorism and homeland security duties, enforcing speed limits hasn't become a high priority despite the dangerous rise in high-speed accidents and deaths.