Tag Archives: Automated Vehicle Location

AVL Technology Enables Smarter, More Efficient Mowing Operations

A pilot project was begun to study the use of AVL technology in mowing operations. Potential benefits include improved mowing efficiency, improved reporting and ease of supervision, reduced paperwork and reduced spread of noxious weeds.

“Using the data we get from the AVL project, we can estimate how long it will take to mow the entire system,” said Douglas Maki, Asset Management Engineer, MnDOT Metro District. “That way, we can plan far in advance of major holidays, when the most traffic comes through our system.”

“The AVL technology can be used to mark newly disruptive weed locations and anything else a mower operator might see, like potholes, damaged signs or guardrails, and excessive or dangerous debris in the field,” said Adrian Potter, Senior Associate, SRF Consulting Group, Inc.

Potter served as the project’s principal investigator.

What Was the Need?

MnDOT is responsible for mowing roadsides along 14,000 centerline miles of highways for environmental and safety reasons. This is an enormous and critical task, requiring efficient use of employee time and mowing equipment, and efforts to avoid the spreading of noxious weeds, which will lead to increased use of herbicides.

A promising technology that many departments of transportation (DOTs) have installed is automated vehicle location (AVL). AVL systems provide a precise geographic location for DOT-owned vehicles so that real-time data can be obtained on field operations. This technology has been used for snowplowing and other fleet vehicle operations. However, only a few DOTs have used it for mowing operations.

To determine if AVL technology should be used in its
mowing operations, MnDOT undertook a pilot project involving 30 of its mowers. The locations chosen were Metro District roadsides, as MnDOT had previously invested in creating a geographic information system map of noxious weeds on those roadsides.

What Was Our Goal?

The goals of the pilot project were to:

  • Generate protocols for hardware installation and software training.
  • Set up the system for communicating data from the mowers to internal MnDOT servers.
  • Develop accomplishment reports based on data collected by the AVL units.
  • Develop and provide initial training to operators and supervisors.
  • Optimize the mower routes used.

What Did We Do?

For the 2015 and 2016 mowing seasons, researchers fitted 30 Metro District tractors with AVL technology, sensors and communication equipment.

The first stage of the project focused on developing the software interface required for the AVL system. The application had to provide a view of the mower’s exact location so that the mower operator could avoid noxious weeds. Data would be collected through an in-vehicle controller unit and transferred to MnDOT for analysis via a Verizon AirCard system installed on each mower.

Mechanics installed metal racks within each of the 30 mowers to protect the Ameritrak AT-500 AVL hardware unit. A video screen was mounted on the top of the rack. A reporting system was developed for use by operators, supervisors and managers. Training sessions were scheduled at the start of each season and when new operators were hired.

Interior view of mower cab showing location of AVL unit.

What Did We Learn?

The project achieved its initial goals of developing protocols for hardware and software, creating electronic reporting and capturing real-time data.

The research team gained the following insights during the planning and field-testing stages of the project:

  • Substantial time is needed to adequately develop and test the AVL software and hardware.
  • Implementing the system also requires considerable time due to resource limitations, and after implementation, it takes multiple mowing seasons to quantify weed and herbicide reductions.
  • MnDOT mower operators and supervisors recognized the value of the AVL system in improving the efficient use of their time, eliminating the drafting of written reports, and giving MnDOT a more accurate record of acreage mowed.
  • Since the tractors operated at such slow speeds, the initial data captured were too imprecise to analyze. But with software adjustments, this issue was resolved.
  • Installation of the AVL unit could have an impact on the operation of the tractor because the additional electrical burden that the unit places on the tractor battery may require the tractor to be sent to the manufacturer for inspection.

What’s Next?

The initial success of the pilot project provided the basis for continued use of AVL technology in Metro District mowing operations during the 2017 season and possibly beyond. MnDOT is currently evaluating whether this project has provided enough data to expand AVL to other districts in the state. The investigators estimate that after full implementation, MnDOT could save $100,000 per year.

MnDOT may consider installing AVL technology in other agency equipment to optimize and monitor maintenance activities.


This Technical Summary pertains to Report 2017-11, “An Innovative Approach to Smarter Mowing, Utilizing Automated Vehicle Location to Enhance Mowing Operations,” published April 2017.

Additional materials:

Knowing While Mowing: GPS Keeps Maintenance Workers Out Of the Weeds

As temperatures fall and days get shorter, MnDOT Metro District maintenance workers are wrapping up a season of mowing grass along roadsides and in medians that they hope will prove a little more efficient than in the past.

Thanks to a research project that installed GPS devices in tractor cabs, operators have a better sense of exactly which areas they need to mow and which areas should be left alone. Five Metro District tractors were tested in 2015. This year, more than 40 tractors were fitted with the automated vehicle location (AVL) technology, which includes a GPS antenna, an on-board central processing unit (CPU) and an in-cab screen with a user interface.

Trisha Stefanski, Metro District asset management engineer, expects one of the biggest benefits of the project to be a reduction in herbicide use. Maintenance crews use herbicide to control the spread of noxious weeds that sometimes get spread during mowing operations. Mapping exactly where noxious weeds are, and providing that information to operators on a real-time, in-cab screen and user interface helps them mow around those areas.

“We’re really hoping it will reduce the amount of herbicide that we’re putting on our roadways by 50 percent,” Stefanski said. “We’re not certain that will be the number, but that’s what we’re hoping for. We think just not mowing those areas will not spread as many noxious weeds and so we don’t have to apply as much herbicide.”

Metro District operators, such as Jesse Lopez, give the AVL technology rave reviews.

“Basically you can see what you shouldn’t mow and what you should mow. So, it makes it easy for me. It’s just like playing a game,” Lopez said. “This actually helps me to optimize what my job is. I know exactly where I’m at and where I’m going. I think everyone should use it – absolutely everybody who is in a mowing situation or a plowing situation.”

In addition, the AVL technology helps maintenance supervisors keep tabs on exactly where their operators are in real time. It also helps supervisors complete reports by automatically providing the geographic areas where mowing has been completed.

Stefanski says the project has gone really well, and she hopes collecting more data over another mowing season will show real savings on herbicide use. In the meantime, she is thinking of other ways AVL technology could be applied to maintenance operations.

“What I really like about the project is that we are taking something used in a lot snow plows and a lot of other technologies – cars, other things, maybe UPS uses them – and we’re putting it into maintenance operations,” Stefanski said. “Having it for mowing, we can also use it for smooth pavements. We can also use it for other things in mowing operations.”

GPS-equipped mowers to save money, reduce noxious weeds

Putting GPS units on MnDOT highway mowers is expected to speed mowing operations and cut herbicide usage by 50-percent in metro area ditches, reducing groundwater contamination.

MnDOT’s Metro District highway maintenance division will be one of the first — if not the first — state agencies in the country to equip the majority of its maintenance tractors with Automated Vehicle Location systems.

Not only will crews be able to effortlessly track their progress — reducing paperwork and freeing time for other maintenance activities — but the AVL’s live mapping software will help them avoid noxious weed patches, thereby reducing their spread.

Last year, MnDOT tested the GPS software on five mowers.
Last year, MnDOT tested the GPS software on five mowers.

“AVL alone enables the tracking of vehicle positions, but when combined with equipment sensors and an on-board monitor with user interface, it becomes a very innovative way to reduce operation costs,” said MnDOT Project Engineer Trisha Stefanski, who applied for funding from MnDOT’s Transportation Research Innovation Group for the pilot project.

Vehicle tracking systems have been shown to reduce chemical usage by crop farmers, improve route efficiencies in truck driving and help cities and counties track snowplows.

The on-screen mapping shows the location of weed patches, so mowers can avoid them, reducing their spread.

MnDOT Metro, which tested five AVL units last year, hopes to equip as much of its remaining fleet as possible.

In the grant application, Stefanski estimated the technology will pay for itself in about a year’s time, largely due to herbicide savings.

Noxious weeds

MnDOT is required by law to manage certain noxious weeds along its highways. Each year, weed inspectors survey one-quarter of metro ditches for weeds, which enables them to concentrate eradication efforts on the worst areas.

Touch-screen maps will contain the noxious weed locations so operators can see weed patches and mow around them.

Herbicide usage is estimated to drop an estimated $100,000 to $150,000 per year. (This estimate was based on the original funding request. Final numbers haven’t been released.)

Operators can use the on-screen map to mark the location of new patches of noxious weeds.

Noxious weeds like Wild Parsnip — which can cause painful skin boils — might even be eradicated, reducing the risk for field crews, such as construction workers and Adopt a Highway volunteers.

Until now, maintenance crews have relied on paper maps to identify weed locations, which is less effective.

“What’s better, looking at a live screen when you’re going down the road and seeing where weeds are coming up, or trying to refer to a piece of paper?” Stefanski said.

Other advantages

The AVL equipment will also allow for automated reporting.

Mower operators can use the on-board AVL monitor to mark the location of guardrail hits, potholes, washed-out culverts, debris and unmarked noxious weeds.

Operators can electronically mark the location of guardrails, debris, potholes and more.
Operators can electronically mark the location of guardrails, debris, potholes and more.

Currently, operators must track their activities using hand-written forms or spreadsheets in the office.

The AVL system will also automatically track their location history, allowing operators to optimize their routes based on how long it took to mow segments in the past.

It will also be easier to answer questions from the public, who want to know the last time a certain ditch was mowed.

“Making everything geographically located adds so much analysis opportunity,” Stefanski said.

MnDOT also has AVL technology on an herbicide applicator to better track where it’s sprayed. Other future potential applications including pothole patching and road sweeping operations, Stefanski said.