Plowing ahead with GPS

It’s spring, but in much of the country, snow drifts already loom large in the minds of public-works officials. As they plan for next winter, some public-works directors are turning to satellite tracking systems to help improve their snow removal operations.

“We’ve already started talking about the things we want to do for next snow season,” said Michael Gantick, director of public works for South Windsor, Conn., which last year started using GPS receivers and Blackberry wireless phones to monitor their snow plows.

In fact, South Windsor’s department of public works (DPW) has used the mobile devices to keep tabs on several different operations over the past year, including street sweeping, leaf collecting and lawn mowing on athletic fields.

South Windsor’s tracking system uses an external GPS receiver, attached to a vehicle’s windshield, to acquire location data. The receiver transmits locations via a Bluetooth link to a Blackberry phone. The town doesn’t use the GPS receiver in the phone because that chip can’t always pick up signals from enough satellites to identify a position, said Scott Roberts, the town’s director of information technology.

The driver plugs the Blackberry into the dashboard power outlet to keep the phone charged. The mobile phone transmits the location data to the Internet via Sprint Nextel’s wireless network. A server at the DPW collects the data and displays it on a map, using the town’s ESRI geographic information system and an application called Freeance, from TDC Group in Dayton, Ohio.

Town officials also use Freeance to create data collection forms on the Blackberries, with different forms for snow plowing, leaf blowing and other processes. “The supervisor sets it up for the driver, starts the form, picks which truck it is and initializes all the GPS functionality,” Roberts said.

Town officials chose this set of technologies partly because it cost less than the dedicated automatic vehicle location (AVL) systems they evaluated. Windsor paid $10,000 for the Freeance software and $6,000 for 20 Blackberries, Gantick said. Officials like that they can move the mobile devices from one piece of equipment to another and that they can use their own GIS software, including all the attribute data they collect, rather than a commercial mapping system, he said.

The tracking system isn’t flawless: as vehicles travel around South Windsor, they encounter the occasional wireless dead spot. But that’s not a big deal, Roberts said. The Blackberry stores the positions it acquires and then transmits them when it re-engages with Sprint’s network.

However, powering the Blackberry is a bit of a challenge, Gantick said. “When you’re using it as a data collector, it really sucks down the battery life. That’s why we’ve plugged it into the cigarette lighters.” Using the wireless phones in harsh environments also is risky, he said. “We’ve had some that have fried on us.”

Despite these problems, the system has delivered on its promise. Last fall, for instance, it saved the town money by allowing the supervisor of the leaf collection crews to go home early, Roberts said. Instead of waiting for crews to come back and report on their work, the supervisor followed their progress on screen and used that information to immediately update South Windsor’s Web-based leaf collection hot line.

In winter, the system tells supervisors when plow drivers stray onto the wrong routes, and it helps them to redeploy drivers where the need is greatest, Gantick said. If residents complain that plows are speeding or that the plow missed their road, officials can check the facts in the system’s database.

The GPS also was helpful during an emergency last winter when an ambulance driver needed a road cleared, Gantick said. “We could look at the map and see which plow was closest to the point where the ambulance was supposed to be and dispatch the closest vehicle.”

Like Gantick, public works officials in Columbia, Mo., have discovered that a snow plow-tracking system is a good tool for fielding citizen complaints. “We get worlds of phone calls from people saying we have not been in a specific area,” said Dave Daly, the city’s street and storm-water manager. In cases like those, Columbia’s DPW used to send a supervisor into the field to investigate. Not anymore. “We can continue working and just look at the map and say, ‘Yeah, we’ve already been there.'”

In December 2007, Columbia bought 19 GPS units for its snow plows and started tracking them through a service provided by WebTech Wireless of Burnaby, B.C. The city since has added 21 units to equip dump trucks, pickup trucks and other vehicles operated by the DPW’s streets division.

WebTech’s Quadrant tracking system transmits location data via AT&T Mobility’s wireless network to a service center operated by WebTech. City of Columbia personnel access the information through a browser, viewing vehicle positions on a map. Because WebTech offers a variety of sensors along with the GPS receiver, the system can track when drivers start and stop their engines and, in the case of snow removal, when they raise or lower the plows and when they’re spreading cinders or salt.

Because they know that supervisors can monitor their work, drivers tend to stick to the correct routes and shut off their engines when they stop, saving the city money on fuel, Daly said. The system also offers more proactive methods for keeping drivers on task. For example, Daly can set up an on-screen “geofence” around the area where a group of trucks is working. “If they leave that area and go somewhere else, it sends us an alert,” he said.

Besides helping supervisors monitor snow removal, the city plans eventually to give that capability to residents. The information-technology department is working on a Web-based map that will show, in real time, which streets have been plowed, sanded and/or salted. City officials estimate that the map will go online next winter.

In Massachusetts, the state highway department (MassHighway) already has progressed to a second-generation solution for tracking snow plows. In 2003, the agency gave Nextel phones to 2,900 contractors who operate plows for the state. Over the past two winters, MassHighway has phased out those portable phones and started relying solely on GPS devices that are permanently installed in state-owned vehicles, whose drivers supervise the contractors.

MassHighway originally distributed the Nextel phones so it could oversee the plowing contractors and efficiently redeploy plows as needed, said Frank Tramontozzi, the agency’s chief engineer. The phones transmitted location data over the Sprint Nextel network. Personnel in each of the state’s snow plow depots used software from @Road, a division of Trimble Navigation in Fremont, Calif., to track the plows that worked out of that facility.

Like their counterparts in South Windsor, officials in Massachusetts discovered that they couldn’t rely on GPS-equipped cell phones to compute their positions accurately. Drivers didn’t always set the phones where they could get signals from at least three satellites, Tramontozzi said. “Depending on where the driver of the vehicle had placed the Nextel phone — on the seat beside him, or in the glove compartment — the accuracy was diminished,” he said.

Problems also occurred when contractors forgot to switch off their phones at the end of a shift. “If you don’t turn it off, then the software thinks you’ve been on the clock until the next snowstorm,” Tramontozzi said.

While it was handing out the phones in 2003, MassHighway also was hard-wiring GPS devices into its snow plows and other vehicles. Those systems also use the Sprint network to transmit position data. They’re more accurate than the phones because the devices’ external antennas always can see at least three satellites, Tramontozzi said.

The installed devices also are better for tracking hours worked, since they switch on and off with the vehicle’s engine, he said. “As soon as [the drivers] turn the key and start it, you know where their position is. And as soon as they shut it off, you know where they’ve stopped their vehicle.”

These days, instead of tracking every plow on the road, MassHighway uses the @Road software to track just the state-owned vehicles. During a snowstorm, six or seven contractors travel in a convoy with a state-employed supervisor, who drives a GPS-equipped vehicle. By tracking the supervisors, managers can track the work of the entire fleet.

And they don’t need to keep an eye on every vehicle all the time, said Tom Loughlin, director of statewide highway operations at MassHighway. “Our employees know that the device is there. There’s now kind of an honor system in place,” he said. “Even if we don’t see it the moment it happens, we have a record of where the batteries [of trucks] were and what they were doing.”

MassHighway also is exploring other uses for GPS. For example, employees who go into the field to replace damaged highway signs will carry handheld computers equipped with GPS. As they enter data about their work, the device will capture the location and automatically update an asset-management database.

“The technology has changed. It’s still changing,” Tramontozzi said. “We continue to test and use it. As it becomes better and better, we’ll be utilizing it more and more.”

Four snow plow-tracking solutions