You may already be aware of autonomous equipment use in mining operations in the form of Volvo CE’s HX2 autonomous, battery-electric load carriers or Caterpillar’s autonomous mine trucks.

What you may not know is that this autonomous technology is also making its way into asphalt paving jobs. Autonomous equipment can make a job site safer and save fuel consumption and operations costs, as well as free up skilled employees for other tasks and help address the workforce shortage the construction industry is currently experiencing.

“[In the mining sector], highly standardized work is carried out in closed systems; there are few points of contact with the outside world and few unforeseeable influences on the process,” said Dr. Stefan Klumpp, Chief Technology Officer of Hamm, Tirschenreuth, Germany, in a 2017 announcement from Hamm. “In road construction, by comparison, the processes are far less clear-cut and less easy to structure. Every construction site is a little different. There is also much more contact with the surroundings (and thus more potential hazard), and user behavior is not uniform.”

Despite the challenges, companies like Hamm and Caterpillar, among others, are moving forward for a safer, more efficient tomorrow.

Autonomous Equipment in Action

Despite obvious differences between mining and paving, many of the first autonomous machines to be headed for the paving train are also material transport vehicles.

Last October, Built Robotics announced its Autonomous Track Loader (ATL), which is a compact track loader that can perform excavation, grading, pad prep, compaction and other tasks without an operator. This is made possible by the ATL’s LiDAR, which are essentially the machine’s eyes on the jobsite, and its GPS sensors to assist with navigation and precision tasks.

Also last fall, United Rentals, which provides more than 3300 equipment and tool classes for industrial and construction sites in the U.S. and Canada, deployed its first autonomous machine on the job site, a Bobcat skid steer moving materials around the job site.

Another autonomous machine of interest to paving contractors is the autonomous impact attenuator truck from Royal Truck and Equipment, Coopersburg, Pennsylvania.

The company’s first fully autonomous attenuator truck was deployed in Colorado last year. Autonomous attenuator trucks have already been tested in Florida, but this is the first time one has been deployed without a safety rider.

CDOT’s Autonomous Impact Protection truck is demonstrated on a Colorado highway.

The Colorado DOT had purchased the driverless attenuator truck to be the shadow vehicle behind a human-driven line painting truck.

“That operation moved at around 5 to 7 miles per hour,” said Royal’s Government Account Manager Fred Bergstresser. “Until now, there needed to be a driver in the ATMA protecting that line painting truck.”

However, by equipping the lead vehicle with a highly precise GPS system, it could transmit the information the attenuator truck needed to safely follow behind while avoiding obstacles.

After the success of this initial test, the autonomous TMAs are now approved for full use in Colorado’s district 4 by both the Colorado legislature and the Colorado State Police. The Colorado DOT will be adding more driverless attenuators to their fleet by the end of 2018, with a goal to get an autonomous TMA behind every mobile maintenance operation in the state, Bergstresser said.

“CDOT has also initiated a pooled funding study with the Federal Highway Administration that around 10 other state DOTs have joined, Bergstresser said. “They’re pooling funds to do additional studies on autonomous TMAs for further use cases, like behind sweeper trucks and mowing operations.”

Royal also has a driverless attenuator in action in London, being used behind a cone setting truck during a 10-week live trial with international road construction company, Colas, and Highways England.

One of our barriers now is that a number of states don’t have legislation allowing for the use of autonomous TMAs,” Bergstresser said. On September 26, 2018, the Pennsylvania Senate unanimously passed SB 1096, which allows the use of highly automated work zone vehicles in Pennsylvania. A companion bill, House Bill 1958, also passed unanimously in the House. “It is our hope that they both will now be sent back to the House and Senate respectively for final passage and then to the Governor for signature.”

Autonomy on the Paving Train

When it comes to autonomous equipment operating within the paving train, both Hamm and Caterpillar are working to develop self-driving compaction equipment.

“Compactors are a good place to start because they utilize processes with a high level of repetition, which can lead to operators losing concentration and performing inconsistently,” said Bryan Downing, Global Sales Consultant of Caterpillar Paving Products. Downing also said that autonomous compaction equipment can improve uniformity and consistency.

“Poor layer durability often can be attributed to inconsistencies in processes, such as rolling pattern variations (poor pass coverage, improper vibratory system on/off variation or incorrect use of amplitude or frequency),” Downing said. “With the use of autonomous systems and semi-autonomous (operator assist) systems, the roller processes will be more consistent and precisely executed.”

Hamm also sees the potential for a self-driving compactors, a concept the company first announced it was working on in 2017.

“Rollers for asphalt and soil compaction will be among the first vehicles in which such systems will widely establish themselves,” Klumpp said. “This is because, in many respects, they are closer to cars than many other types of machine are. This is why we have been dealing with this subject for some time at HAMM.”

The first step, Klumpp said, is to ensure the machines’ sensors can appropriately measure stiffness to accurately decide frequency and amplitude. According to Klumpp, “the automation of the working process of the machine has to be optimized and further developed. As a result, the driver can concentrate on driving.”

The following piece of the puzzle is to allow the machine to make passes autonomously, with a operator on board just in case. The final step is to have sensors successfully monitoring the machine’s surroundings so it can begin to operate fully autonomously.

Klumpp said the two main reasons to automate this process are to improve quality and solve the labor force shortage.

“When we shared the article about our efforts in 2017, immediately we got calls from several companies asking when they could buy it because they cannot find enough labor force to realize their projects,” Klumpp said. “But we still have to concentrate the knowledge of the driver into rules that a machine can follow.”

In the 2017 announcement from Hamm, the company also outlined how fully autonomous compaction equipment could offer other benefits, such as significantly larger drum diameters, bigger water tanks and more space for the batteries of electrically powered rollers.

Where To Next?

Although OEMs continue to invest in the possibility of autonomous equipment on the paving train, most commercially available self-driving equipment is still a long ways off.

Klumpp estimates it will be at least another 10 years before a fully autonomous roller will be commercially available.

Automating other equipment on the paving train is even further afield.

“The asphalt paver will be one of the most difficult machines to make autonomous on the paving train because of its interface with trucks or material transfer vehicles and its connection to the floating screed,” Downing said. “This is a convergence of a lot of processes and variability.”

“We’ve built a roadmap and we are constantly working on this mission,” Klumpp said. “This will not happen tomorrow, but the path to get there is clear.”

It’s an unfortunate fact that vehicle intrusions are one of the leading causes of death in the road construction industry, resulting in tens of thousands of work zone crashes and hundreds of fatalities each year.

What’s even more devastating is that many of these fatalities could have been prevented.

The National Highway Transportation and Safety Administration estimates that 80 percent of all accidents are due to distracted drivers, looking away from the road to check a text (4.6 seconds), change the radio station (2 seconds) or search for a dropped cell phone (10+ seconds). All while their vehicles travel the length of a football field every 3.7 seconds.

Here’s another number: 6 seconds.

That’s how long it takes a worker to run five lane widths—more than enough to avoid an oncoming vehicle.

When it comes to work zone safety, every second counts.

That’s why Oldcastle Materials has developed its AWARE system. The system, which stands for Advanced Warning And Risk Evasion, tracks traffic and crew members within a work zone and sounds alarms and alerts both to drivers and to workers at risk of a collision.

Oldcastle, the largest asphalt manufacturer in North America, started to develop its AWARE system after experiencing a handful of fatalities in 2013 and 2014 due to lane intrusions.

“We were following all the regulations and recommendations at federal, state and association levels to make our organization safer, but at the end of the day, we were still having catastrophic events,” said Curt Davison, director of AWARE technology at Oldcastle Materials. “So, we asked ourselves what we could do beyond best practices and beyond regulations to make our workers safer.”

So, they began to develop AWARE with nothing more than a sheet of paper, a pencil, and an end goal: keep workers safer in the work zone.

Davison hopes to begin implementing the system company-wide in May of 2018.

How the AWARE System Works

As you can learn when watching the AWARE video in the link below, the system includes one or more sensors, a GPS-based alert unit for the worker, a number of threat deterrents, and a base station app for iPhone and iPad.

The sensors use radar to track the position and trajectory of vehicles within a range of up to 600 feet. When a vehicle is about to enter the workzone—when the sensor detects it as a threat—the sensor triggers audio and visual warnings for the driving public and individual alerts for workers who might be in harm’s way via their GPS-based units. The system will also begin recording video with an onboard camera for use in accident investigations, if necessary.

Today, there are two different types of solutions within the AWARE system, Davison said. One is a freestanding cart to set up by the flagger and the other is dedicated to safety in the work zone.

The system can be used for a number of applications, from line striping and traffic control setup, to multi-lane construction, flagger safety or lone-worker scenarios like road maintenance and sign placement.

Within the typical paving train, Davison recommends including in the system the paver and each roller. The QA/QC tech should also have one on his truck, since he’s often quite a ways back from the rest of the crew. The system can also include other operations such as milling and maintenance equipment.

When the system detects a threat, it will automatically trigger audio and visual warnings for the driving public and individual alerts for workers who might be in harm’s way. It will also begin recording video with an onboard camera for use in accident investigations, if necessary.

The system works to reduce false alarms, preventing desensitization in workers. When a real threat has been identified, the threat deterrents will activate, emitting whatever sound and strobe pattern the AWARE user has chosen.

Worker and equipment locations can be viewed in real time via the system’s companion app for iPhone or iPad. With the app, users can control basic functions of the system, including lane width, work zone type, minimum and maximum speeds, and conservative and aggressive reaction times for warnings.

Implement, Adopt and Stay Safe

The AWARE system’s sensor monitors traffic within a 600-foot range. Additional sensors can be mounted to other pieces of equipment in the work zone.

Last year, Oldcastle piloted the system in eight states on 13 different crews to continue to refine it, and one of the major improvements has been in usability.

“Our crews have a hard, hot job and they’re busy doing what they’re doing,” Davison said. “So we had to make it super simple.”

Davison estimates it takes about two hours to install the system on each piece of equipment in the work zone. After that, the AWARE system is very easy to use on a daily basis. The AWARE sentry for the flagger station takes less than a minute to set up and the entire work zone solution takes only a few minutes.

Other improvements in usability include reducing the weight of the sentry to less than 50 pounds and making the user interface of the app easier to use.

Davison also conducts an hour of training about the system before sending it out with new crews. He also recommends making the system a part of each crew’s morning safety talk, to discuss the best exit strategies and other emergency procedures for the job.

“You may only have seconds to respond after the system goes off, so that isn’t the best time to ask yourself where you should go,” Davison said. The system gives between one and six seconds of notice, depending on the situation. “One second may be enough, but you have to have a plan in place.”

Although making the AWARE system easier for workers to use is important, the real proof is in the pudding.

Davison shared a story about a flagger who wasn’t sold on the system when they deployed a threat deterrent next to him on the job. Then, a semi came towards him at a high speed. As it barreled closer to the flagger, it wasn’t slowing down. The system sensed its speed and the lights began to flash. Still, the semi didn’t slow down. The system’s lights started flashing brighter. When the semi still didn’t slow down, the alarm sounded. By that point, the flagger could see inside the cab and noticed the driver’s eyes go wide as the alarm sounded, apply the brakes, and come to a stop only inches from the flagger’s original position.

“Please understand that this technology, the AWARE system, does not replace the need for safety best practices in the work place,” said Oldcastle VP of EHS Lee Cole. “Rather, the two should work together to provide the safest work place possible.”

AWARE, Beyond Oldcastle

During presentations at industry events, Davison has realized how important a system like this is to all paving operations, as well as in other industries.

“A lot of people from a lot of industries–construction, police, truck drivers–have come up to ask me if the system will be available outside of Oldcastle,” Davison said. And it will–eventually.

“We want to refine the system a bit before releasing it outside of Oldcastle,” Davison said. “Right now, the sensors are still learning and rating threats, from false alarms and alarm-no-harm situations to near misses and minor and major incidents.”

Davison expects to refine the system internally throughout 2018, but hopes to make it available to other companies and industries in 2019.