DANVILLE - Motorists driving through the intersection of Routes 54 and 642 near Danville unknowingly are taking part in a traffic study for the Pennsylvania Department of Transportation.

That's because the data related to origin, destination and direction of travel is coming from their cell phones or navigation devices.

It is part of the modern technology being employed to try to make safer an intersection on a road that when built in 1970s was supposed to be a high-speed connection between Interstates 80 and 81.

However, the four-lane divided highway was completed only between I-80 and Danville. Located close to the middle of that stretch is the intersection with Route 642, the scene of numerous and sometimes fatal accidents.

Lots of the accidents are caused by operator error, Montour County Commissioner Ken Holdren said.

The Route 54 speed limit at the intersection is 55 miles per hour and there are motorists making left turns and changing lanes, he said.

PennDOT last year proposed a roundabout as a safety improvement, but it was met with public opposition.

Although a roundabout is still an option, PennDOT's consultant MacMahon Associates is gathering more information, some of which is coming from cell phones or in-dash navigational devices.

All entities involved in the study stress no personal information is used.

"Basically we are seeing a dot-moving through the area," Eric Weber, PennDOT's project manager said in describing the data it gets.

MacMahon is utilizing StreetLight Data of San Francisco to provide it with information that includes the number of vehicles passing through the intersection or making turns.

That information from smartphones is recorded when apps like those used for weather, shopping and dating ping GPS satellites or known wi-fi hotspots, StreetLight spokeswoman Laura Schewel explained.

StreetLight does not use cellular tower data in its analytics and, she said, location records that are incomplete or erroneous are discarded.

For example, she said, data showing a trip starting at 60 mph on a highway would be removed because the true trip origin could not be identified.

StreetLight's algorithms are designed to filter out data from multiple devices in a vehicle and bicycle and pedestrian trips, she said.

Only location records are received or stored by StreetLight, she said. It is impossible to trace the location record back to any specific device, she said.

Using cell phone data eliminates the need to stop vehicles to obtain origin and destination information, said Chris Bauer, general manager of McMahon's Camp Hill office.

"It's much more efficient," he said.

While not necessarily used for transportation planning initially, the technology for tracking locations with cell phones has been around for quite some time, Schewel said.

PennDOT spokesman Rich Kirkpatrick said he does not know how long the agency has used cell phone data in the planning process.

It has for a number of years had a contract with INRIX, a Kirkland, Washington, firm that collects data from vehicles to provide real-time speeds on roads throughout the state, he said.

Information from INRIX and other sources allows PennDOT to provide current traffic information on message signs and its 511 travel information services, he said.