And sometimes it even catches killers.
Cops in the know have sometimes referred to their vehicle code  manuals as "probable cause bibles." And with good reason. After all, a  traffic stop can open the doors to a legal search of a vehicle for  illegal substances, stolen goods, and even dead bodies.
What follows are some examples of how alert traffic officers have  helped end the careers of some of America's most prolific murderers.
Case #1: Randy Kraft
Violation: Possible Drunk Driving
On May 14, 1983, officers of the California Highway Patrol noticed  that a Jeep driven by Randy Kraft was weaving in its lane on Interstate  5. They pulled Kraft over near the south Orange County suburb of Mission  Viejo. Kraft got out of his car and walked to the officers.
There on the side of the freeway, the CHP officers had Kraft submit  to a field sobriety test. The computer programmer and former Marine  failed the test.
Kraft was taken into custody and secured in the back of a CHP patrol  car. The "chippies" then conducted a search of his Jeep.
And they found a lot more than a few empty beer bottles or an open  fifth of Jack. On the front passenger seat of Kraft's Jeep was the  shrouded body of a young Marine, Terry Gambrel.
Subsequent investigation revealed that Gambrel had been heavily  sedated and then strangled with a ligature. It was later learned that  Kraft was the "Southern California Strangler," a prolific murderer who  picked up young men-primarily Marines-drugged them, tortured them,  strangled them, and pushed their bodies out of his car as he sped south  on the freeway.
Kraft was convicted of 16 murders. But authorities believe he may  have been responsible for more than 67. He awaits execution on  California's Death Row.
Case #2: William Lester Suff
Violations: Illegal U-Turn/ Expired Registration
On Jan. 9, 1992, an officer of the Riverside (Calif.) Police  Department spotted a 1989 Mitsubishi van making an illegal U-turn. As  the officer closed on the vehicle, he also noticed that its registration  was expired. He effected a traffic stop and soon discovered that the  van's driver, William Lester Suff, was operating his vehicle on a  suspended license and that he was the owner of many unpaid traffic  tickets.
Suff was detained on the traffic violations. Which was really bad  luck for him because a check of his van's plates spurred interest from  investigators who were working the murders of numerous prostitutes in  the Riverside area. Suff's van was the same one that had been seen at  the dump sites where the murder victims' bodies were found.
Further investigation resulted in an indictment of Suff on 12 counts  of murder spanning seven years. Suff was convicted of rape, murder, and  mutilation in 1995. He is on California's Death Row.
Case #3: Theodore "Ted" Bundy
Violation: Too Many to List
Ted Bundy is one of the most infamous serial killers in American  criminal history. From 1966 to the late '70s, he murdered more than two  dozen young women and teenage girls in Washington, Utah, Colorado, and  Florida. Bundy was also one of the world's worst drivers, and a number  of alert cops pulled him over for numerous traffic violations throughout  his life.
On August 16, 1975, Bundy was driving a light-colored Volkswagen near  Salt Lake City with his lights off. This caught the attention of Utah  Highway Patrol Officer Bob Haywood, who lit up Bundy's car. A chase  ensued. Bundy was arrested for evasion of police and released on his own  recognizance. A subsequent investigation resulted in Bundy being  convicted of aggravated kidnapping. He was sentenced to one to 15 years  and extradited to Colorado to stand trial for murder.
Bundy escaped custody on June 7, 1977, but once again his driving  skills piqued the interest of a traffic officer. He was arrested on June  13 in Aspen for driving erratically in a stolen car.
But holding on to Ted Bundy was not easy. He escaped again on Dec.  30, 1977. And this time, he didn't hang around Colorado. Instead, he got  out of the state, bounced around a few different locations, and came to  rest in Tallahassee, Fla.
In Florida, Bundy resumed his hobby of terrorizing and murdering  young women, particularly students at Florida State University. And once  again, Bundy's driving garnered the attention of an alert officer. But  while the officer ran Bundy's plates, the killer escaped, returned to  his apartment, wiped it clean, and stole yet another Volkswagen.
Bundy fled to nearby Pensacola. There, a patrol officer spotted  Bundy's VW, ran its plates, and learned that the vehicle was stolen.  Bundy was arrested, and this time he didn't escape. He was tried and  convicted for several murders of Florida State coeds. He sat down in  "Old Sparky" on Jan. 24, 1989, and he didn't stand back up.[PAGEBREAK]
Case #4: David Berkowitz
Violation: Parking Next to a Fire Hydrant
New York City's ".44 Caliber Killer," David Berkowitz, terrorized the  city during the Carter years until he was arrested in 1977. Berkowitz,  who called himself the "Son of Sam," killed six young men and women and  wounded nine others during his bloody career.
The Son of Sam's MO was to walk up on couples sitting in parked cars  and open fire on them with his .44 caliber Charter Arms revolver.  Ironically, it was a parking violation that helped put him away.
On July 31, 1977, Berkowitz attacked Stacy Moskowitz and Bobby  Violante who were parking at Gravesend Bay in Brooklyn, killing  Moskowitz. Berkowitz was already a person of interest in the  investigation, but the first solid evidence that police gathered against  him was a parking ticket that was written in the Gravesend Bay area the  night of the Moskowitz murder.
Berkowitz's home was put under surveillance, and officers of the  Yonkers Police Department arrested him. Under interrogation, Berkowitz  admitted to being the Son of Sam. He was convicted and sentenced to 364  years in prison. Berkowitz now lives in Attica State Prison, where he  converted to Christianity and now refers to himself as the "Son of  Hope."
Case #5: Joel Rifkin
Violation: No License Plate
If former gardener and prolific murderer Joel Rifkin were to give a  lecture to aspiring serial killers, he would probably lead off with the  following advice: "Put a license plate on your vehicle."
At 3:15 a.m. on June 28, 1993, New York state troopers Sean Ruane and  Deborah Spaargaren spotted a Mazda pickup with no plate cruising on  Long Island's Southern State Parkway. They turned on their flashers, and  the driver sped away. A high-speed chase ensued, involving multiple  officers and ending with the Mazda crashing into a telephone pole.
If you had been Rifkin, you would have run, too. Not only did his  pickup have no plate, there was a decomposing body of a woman inside the  bed.
A subsequent search of the home that Rifkin shared with his mother  and sister led to even more grisly evidence of his deeds, including a  chainsaw and human blood found in the garage. Rifkin was convicted on  May 9, 1994. He was sentenced to 183 years on seven counts of murder,  with 10 counts outstanding. His current home is the N.Y. State  Correctional Facility in Clinton. And wouldn't it be great irony if he  spends his days making license plates?
Case #6: Timothy McVeigh
Violation: No License Plate
Next to Osama Bin Laden, Pendleton, N.Y.-born Timothy James McVeigh  is the greatest terrorist enemy the people of America have ever known.  The truck bomb that McVeigh parked in front of the Alfred P. Murrah  Federal Building in Oklahoma City on April 19, 1995, killed 168 people  and maimed hundreds more.
In some ways the Gulf War veteran was a mastermind. In others, he was  a moron. Investigators caught McVeigh through good old-fashioned  detective work by the FBI and because he was too stupid to put a license  plate on his getaway car.
We can thank Charles Hanger, an Oklahoma Highway Patrol officer, for  making this collar. The day of the bombing he spotted McVeigh's Mercury  Marquis cruising down I-35 near Pawnee, Okla., without a plate. Hanger  made a traffic stop, used probable cause to search the vehicle, and  found a loaded firearm. McVeigh was arrested and, three days later, the  FBI came to get him.
On June 2, 1997, a federal jury convicted McVeigh of killing eight  federal employees who were victims of the Oklahoma City bombing. Eleven  days later, the same jury voted that he was a waste of human life.
McVeigh was executed by lethal injection on June 11, 2001, at the  U.S. Federal Penitentiary in Terre Haute, Ind. His co-conspirator Terry  Nichols got life. Other accomplices are suspected by some authorities.[PAGEBREAK]
Case #7: Wayne Williams
Violation: Stopping on a Bridge
The Atlanta Child Murders are some of the most controversial criminal  cases of the last 50 years. In 1979 and 1980, as many as 30 young  African Americans-primarily children and teenagers-were killed by a  serial murderer or murderers in the Atlanta area.
Atlanta's African-American community was convinced that the slayings  were the work of white men, presumably members of the Ku Klux Klan or  another hate group. Detectives working the case found that theory less  than credible. Investigators caught a break in April 1981 when the  bodies of Jimmy Payne, 21, and William Barrett, 17, were pulled from the  Chattahoochee River. They decided to watch the bridges and see who was  dropping bodies.
Before dawn on the morning of May 22, 1981, a rookie officer  positioned below a bridge heard an object fall into the water. Above him  two other officers stopped a vehicle driven by Wayne Bertram Williams  and cited him for stopping on a bridge. They searched his car and found  nothing. Two days later, the body of Nathaniel Carter, 27, was pulled  out of the river downstream from the bridge.
Wayne Williams was arrested on June 21 and charged with Carter's  murder. On July 17, he was indicted for the murders of Carter and Payne.  Forensic evidence was used to make the case, and Williams was convicted  on Feb. 27, 1982. He was sentenced to life in prison.
Many people, including some officers, believe that the majority of  the Atlanta Child Murders remain unsolved. Others say that Williams is  the killer. The debate rages to this day.
Case #8: Bruce A. Davis
Violation: Tampering with a Vehicle
There are several things that can be learned by studying the case of  Bruce A. Davis, a homicidal drifter who confessed to dozens of murders  that occurred from 1969 to 1971.
Number 1: Traumatic events can lead to later violent behavior. Davis  claimed that he was raped by a gay man when he was 13. He spent much of  his adult life preying on homosexuals.
Number 2: Never turn your back on a convicted killer. While serving  time for a Chicago-area murder, Davis was transferred to the Illinois  State Prison in Menard in 1982. There, on Oct. 24, he somehow got his  hands on an axe and attacked his guard. The guard was mortally wounded  and Davis escaped.
Number 3: Somebody breaking into a car could be a serial killer on  the run. Seven days after his escape from Menard-on Halloween  night-Davis came to the attention of deputies from the Fayette County  (W.Va.) Sheriff's Department. He was apprehended after trying to break  into a car in the town of Smithers.
Davis received a life sentence for killing his guard during the  escape from Menard. So, he figured he didn't have anything to lose. His  confessions closed 32 murders in cities coast to coast and in San Juan,  Puerto Rico.
Case #9: Larry Eyler
Violation: Parking on a Highway
Like many other serial killers throughout history, Larry Eyler was a  conflicted homosexual who preyed on gay men.
Eyler's first known victim was Jay Reynolds, found stabbed to death  on the outskirts of Lexington, Ky., on March 22, 1982. He then went on a  murder spree that resulted in the deaths of 20 men and boys. All of  their bodies were dumped on the sides of roads in Kentucky, Indiana, and  Illinois-a practice that led to the press dubbing Eyler "The Interstate  Killer."
Eyler's last intended victim owes his life to an Indiana Highway  Patrol Officer who noticed a pickup truck parked along I-65 and saw two  men moving toward the tree line. The sharp-eyed officer quickly realized  that one of the men was tied up. The officer investigated and  discovered that Eyler had picked up the other man for sex and then tied  him up. A subsequent search of Eyler's truck yielded a blood-stained  hunting knife. Eyler was taken into custody and later released.
But he was now the investigators' prime person of interest. Forensic  evidence, including tire tracks and boot imprints, linked Eyler with the  murder of Ralph Calise who had been found in a field near Lake Forest,  Ill. The blood on the knife matched Calise, who had been stabbed 17  times. Unfortunately, a pre-trial hearing suppressed the evidence found  in the truck. And the other forensic evidence was ruled fruit of the  poisonous tree.
Eyler was freed and he continued killing. But he got really sloppy,  dismembering and bagging the body of a 15-year-old gay hustler before  dumping it in his own garbage. A janitor's dog uncovered that horror,  and the Chicago police arrested Eyler for murder.
The Interstate Killer was convicted on July 9, 1986. He was sentenced  to death by lethal injection, but he died of AIDS in 1994.
Case #10: James E. Swann Jr.
Violation: Running Red Lights
For two months in 1993 the residents of the Columbia Heights and  Mount Pleasant neighborhoods of Washington, D.C., lived in fear of the  "Shotgun Stalker," a man who drove around the area blasting pedestrians  with a shotgun.
Then on April 19, Metropolitan Police Officer Kenneth Stewart saw a  car run through a couple of red lights. Stewart, who was reportedly off  duty at the time, gave chase and captured James E. Swann Jr. Inside  Swann's car, police found a recently fired shotgun.
Swann was arrested and indicted on four counts of murder and 10  counts of attempted murder. He pleaded not guilty by reason of insanity.  Court testimony revealed that Swann was severely schizophrenic, hearing  voices that told him to attack his victims. Swann currently resides in a  Washington area mental hospital.
Dean Scoville is a patrol supervisor with the Los Angeles County  Sheriff's Department and a contributing editor to Police.