Heading north on I-35, Trooper Hanger spotted a battered 1977 Mercury Grand Marquis with no license plate. Its driver was Timothy J. McVeigh who, about 90 minutes earlier, had detonated a truck full of explosives outside the Oklahoma City federal building, killing 168 people in what then was the worst act of terrorism on American soil.
The McVeigh case holds mythic status among police officers, for whom it is a go-to rejoinder to concerns that many traffic stops are pretexts for raising revenue or searching, without cause, for evidence of other crimes. But researchers and some former police chiefs say that for every occasional lucky break, hundreds of innocent motorists are subjected to needless scrutiny, expense and potential danger.
“Because everybody on the road violates traffic laws, that allows the police, who are also in charge of criminal law enforcement, to investigate crime without meeting any of the standards required for criminal investigation,” said Sarah A. Seo, a law professor at Columbia University and the author of a history of traffic enforcement.
As early as the 1910s, Dr. Seo said, departments found that taking on traffic enforcement meant they could hire officers and expand their investigative powers. By 1920, traffic fines helped the Los Angeles police traffic division become “practically self-supporting,” according to an annual report at the time.
“We think that modern police departments and their power came from the need to fight crime,” Dr. Seo said. “Actually, it started with traffic enforcement.”
While tickets and the threat of punishment deter some would-be offenders, the need for municipalities to sustain that revenue model appears to be an incentive for many traffic stops today. An analysis of North Carolina court data by the Federal Reserve Bank of St. Louis found that “significantly more tickets” were issued when localities experienced financial difficulties, suggesting they were “used as a revenue-generation tool rather than solely a means to increase public safety.”
Thirty-one states and Washington, D.C., required annual vehicle inspections before 1976, but many dropped them over time, saying they failed to deliver safety benefits. Indeed, the Government Accountability Office found that vehicle component failure figured in only a small percentage of crashes, and there was no evidence that things like broken taillights were significant factors.
Read More: The Demand for Money Behind Many Police Traffic Stops