If you're worried your car makes a tempting target for an opportunistic thief when parked at night, look no further than the windshield right in front of you.

If the display of a Global Positioning System or satellite radio device stares back at you, the answer might be yes.

Police in various neighborhoods throughout Pittsburgh say thefts of GPS devices and satellite radios have become more prevalent as the products become more popular.

The crimes are most common in the Shadyside, Squirrel Hill and Oakland areas, the South Side business district, and in Stanton Heights and Highland Park in the East End, police said.

Pittsburgh police do not keep statistics tracking specific items stolen from vehicles. But officers in several stations noticed an increase in these thefts in the past year and particularly in recent months.

The total number of thefts from vehicles in July through October of 2007 dropped significantly compared to the same months in 2006.

But in November and December 2007, the most recent month for which citywide statistics were available, thefts from vehicles increased about 13 percent from the previous November and December. Several crime prevention and analysis officers said the thefts of windshield devices may have driven the statistical surge.

"Once they became more common, it started happening," said Matthew White, a crime prevention and analysis officer at the Squirrel Hill station.

These devices, especially when mounted on windshields with a suction cup or Velcro, make the ultimate score for the practical petty thief, police said.

Police said the process is simple for a criminal: smash the windshield, grab the device, and run or drive away.

As long as the thief touches nothing but the device, he or she leaves no fingerprints because windshield glass shatters into too many pieces to pick up prints.

The retail price for satellite radios ranges from about $40 to around $250, while the most expensive GPS devices cost close to $2,000. But when stolen, devices sell quickly for $30 or $40, making them an even more attractive item, police said.

"Most things they'll steal and get three, four bucks for it," said Michael Gay, a crime prevention officer at the East Liberty station.

Most importantly, though, the devices are easily reusable in most cases. GPS companies usually have no way of canceling service to the device, although one of the largest producers of GPS equipment, Garmin Ltd., offers a security lock feature requiring the user to enter a code before using the device, company spokesman Carly Baltes said.

"Often people are disgruntled when they first call in about a stolen GPS," she said, "but eventually they realize they should have kept their device in a secure location."

Satellite radio users can cancel their subscription after the theft, but whoever acquires the stolen device can reactive the radio with a new subscription.

Preferring not to act as a law enforcement agency, Sirius satellite radio encourages its customers to report stolen radios to police so they can retrieve them.

"Police can, and do, subpoena Sirius for customer information associated with a stolen radio and its identification number," spokesman Patrick Reilly said. "If a stolen radio is reactivated, that very information allows police to track it down."

XM radio, the other major satellite provider, declined comment.

Since the mounted devices are so easy to spot from the street, the thefts tend to be crimes of opportunity, making them difficult for police to prevent.

Officers in the South Side recently made an arrest of a man stealing a GPS device when a witness immediately called 911, Zone 3 Cmdr. Larry Ross said. Police stopped a vehicle matching the description of the suspect not far from the scene of the crime and recovered the device.

As was the case with this South Side man, whose name was not released because he is part of an ongoing investigation, police believe individuals stealing the devices resell them for drug money, Cmdr. Ross said.

Most of these thieves escape undetected, however. The best way to prevent such crimes is to take valuable items out of the car.

"People just have to be more careful with their property," Cmdr. Ross said.