Kelly Automotive salesman Richard Kelly adjusts the GPS navigation system in a Cadillac SRZ on Tuesday at the dealership in Penn Township. The use of factory installed, aftermarket retrofitted and hand-held GPS devices has increased in recent years.

A popular feature offered by car manufacturers is a GPS navigation device, a global positioning system that is fed information from satellites, enabling motorists to find locations while driving.

In addition to factory installation, navigation systems can be retrofitted into the vehicle. Hand-held devices also are available.

John Hunka, operations manager for Kelly Automotive in Penn Township, said consumers wanting more than a hand-held device typically opt for factory installation rather than aftermarket retrofitting.

He said there is a significant cost difference between factory installation running about $1,000 and retrofitting which is roughly $2,500.

Factory installation also provides buyers with a warranty if they buy bumper-to-bumper coverage.

GPS devices can be strictly audio or visual while high-end models have both capabilities.

Visual types display maps while audio devices verbally instruct drivers on what turns to make.

Hunka said the preference for consumers is audio if they can afford only one feature.

"People don't want to take their eyes off the road," he said.

Upper tier GPS devices contain maps of multiple countries and various languages. They also provide longitude, latitude and sea levels.

Hunka said the devices tend to come with upscale models such as Cadillacs.

He estimated more than 50 percent of Cadillacs have a GPS while the devices come in only about 20 percent of Chevrolet models.

At Charapp Ford in Natrona Heights, mid-line to high-end vehicles come with navigation systems.

Phil Behr, Charapp's service manager, said the devices have risen in popularity in the past three years.

In addition to motorists who want help finding various locations, emergency services can rely on a GPS to help save lives.

Frank Matis, director of Butler County Emergency Services, said the devices are more useful to ambulances than to fire trucks. That is because, he said, "The ambulance companies cover a much larger area."

The county uses GPS in its Hazmat vehicles. Matis said the devices come in handy.

"It's really surprising how accurate they are," he said.

Behr agreed, saying a navigation system's map has no discrepancies like some computer mapping programs do.

"They're much cleaner and more effective," he said.