State to monitor JBLM traffic congestion with Bluetooth

Staff writerJanuary 31, 2014 

If you drive Interstate 5 from Lacey to Tacoma and have a Bluetooth device, chances are you’re going to be tracked in the next couple of weeks.

No, it’s not the National Security Agency monitoring your every move. It’s the state Department of Transportation.

The tracking of Bluetooth devices — or, more accurately, the unique address they emit — is part of the state’s effort to study congestion on the I-5 corridor around Joint Base Lewis-McChord.

For those unnerved by the idea of being tracked, transportation officials say there’s nothing to worry about. “We cannot track people or hear conversations, nor do we want to. All we know is the signal,” said Jon Pascal, principal at Transpo Group, the Kirkland-based company deploying the readers.

“We don’t know where it’s coming from; we don’t know if it’s a car or a phone. There’s no way to track it.”

Hands-free ear units, smartphones and tablets all have Bluetooth technology. So do cars — and not just cars that allow cellphones to be wired through the radio. Many newer cars use Bluetooth to report tire pressure and other maintenance needs, Pascal said.

The readers, called BlueMAC, collect a small portion of the individual media access control address, or MAC, that is transmitted by enabled Bluetooth devices.

Forty-seven readers will be installed from just north of state Route 512 in Tacoma to Lacey and from state Route 507 in Yelm to Steilacoom.

A time, date and location stamp will be recorded from Bluetooth devices and uploaded to a server. The data will be combined with other traffic studies to determine how people use the regularly congested stretch of interstate.

Traffic officials assume the bottlenecks in the Lewis-McChord area are from people who use I-5 to get to different points on base, but officials don’t have data to support those assumptions, said Bill Elliott, Olympic region coordinator for the state DOT.

If the study shows that’s the case, it could prompt a recommendation to add arterial routes on base to reduce the number of drivers using the freeway, Elliott said.

This study will help the department learn where people are coming from and where they’re going, he said.

“Doing it manually with people with cameras would have been completely impractical,” Elliott said.

Typically the department uses a person to photograph license plates for these types of studies. With such a large area under review, that was too labor-intensive.

The department knows not everyone has a Bluetooth device and expects the study will capture roughly one-quarter of vehicles using the corridor daily, but that is statistically adequate.

This is the first time Bluetooth readers will be placed in the corridor, but they’re becoming more prevalent around the region. There are some in downtown Seattle.

Other devices that track Bluetooth signals include freeway reader signs that show how long it takes to get to a destination; the signs use the signals of passing cars to generate and update travel times as traffic fluctuates, Elliott said.

For those still leery about being tracked, Elliott offered one last word of assurance.

“We’ve deployed quite a number of these devices on base, and you can understand the folks on JBLM are quite concerned about security and monitoring,” he said. “They reviewed the devices and had no concerns.”

Brynn Grimley: 253-597-8467

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