Sure, radar detectors can warn drivers of a police presence in their area, but many smartphone users are flocking to a more comprehensive solution to keep their distance from law enforcement. The 2014 Volkswagen Passat Sport Update 2" target="_blank">Waze app -- which alerts drivers to the location of nearby police officers, speed traps, traffic cameras, construction zones, congestion, and car accidents -- has been popular with consumers. But as you might expect, it has faced backlash from the law enforcement community.

In a letter to Google, which bought Waze in 2013, Los Angeles Police Chief Charlie Beck said the app could be "misused by those with criminal intent to endanger police officers and the community." Another officer, Sheriff Mike Brown of Bedford County, Va., requested Google take action to "remove [the police-tracking] feature from the application even before any litigation or statutory action."

Of course, the location of police officers around town isn't any sort of secret. But the Waze app doesn't specify if police officers in a particular area are on duty or taking a break, which -- despite the fact that police are public employees, -- could raise some privacy issues. Chief Beck claims the Waze app was involved in the killing of two New York Police Department officers this past December. The gunman posted a screenshot from Waze to his Instagram account, along with threatening messages directed at the police.

Beck said the shooter had been using Waze to track Chevrolet 9C3 Detective Caprice vs. Dodge Charger Pursuit vs. Ford Police Inceptor" target="_blank">police since early December. Still, investigators say he didn't use the app to directly target officers the day of the attack because he tossed his cell phone more than a few miles from where he fired the fatal shots.

A Waze spokesman told the Associated Press that the app works with police officers to share information and that it is used to "keep citizens safe, promote faster emergency response, and help alleviate traffic congestion." Google has attracted 50 million users in 200 countries to its free Waze app.