Solar Roadways: American Ingenuity to Power a Greener Future

There are moments in life when we hear about something that strikes us as so obvious, so wonderful, that we wonder why we haven’t encountered it before. 

Solar Roadways was one of those things for me.

We have accepted roads that exist in a certain way, but what if, in the near future, they could serve purposes other than simply a solid, flat surface for vehicles to drive upon?

Solar Roadways is a company that has developed a technology (of the same name) which began with the idea to turn the surface of our roads into solar panels, and evolved into a way to address numerous problems of our time.

Solar Roadways were first designed by electrical engineer Scott Brusaw in 2009 and are currently in their fifth iteration.

The idea might sound like a futuristic pipe dream, but Solar Roadways has been awarded multiple contracts for research and development from the US Department of Transportation, to the sum of $1.6 million, in addition to contracts from the Department of Defense. Even more exciting, they’ve done highly successful crowdfunding, launching an Indiegogo campaign in 2014 that raised $2.2 million and a StartEngine campaign in 2021 that raised funds by selling stock in the company. It brought in another $2.5 million.

If implemented on a wide scale, Solar Roadways could improve our lives in multiple ways. In addition to making a massive impact in the energy sector, they also have many positive implications for the environment, infrastructure, autonomous vehicles, safety, automation, economics, wildlife conservation, privacy, and more. This article will take a look at what they can do.

Please note, most of what you’re about to read is covered in this video, in case you prefer to watch instead of read.

Solar Power Reimagined

Solar Road Panels (SRPs) are hexagonal panels which become effective power generators when massed together. 

In 2014, the first operational Solar Roadways parking lot came online at the Solar Roadways shop using second generation panels. Much of the information here is based on these second gen SRPs, including the video above. The third and fourth generation increased solar power production and improved many other features. Development of fifth-generation SRPs, designed to be mass produced to bring down costs, began in 2020.

Solar Roadways estimates that for a twelve-foot wide road lane, 15,840 panels would be needed per mile, and that 30 homes could be powered entirely by a single mile-long lane of SRPs at 69% solar coverage (accounting for shade from trees, cars, dirt, etc). A mile of two-lane road with full sun coverage could power 86 homes. The mind boggles at the possibilities. Solar Roadways claims that if all the roads (and other paved surfaces) in the US were Solar Roadways, they could power the country three times over. In fact, these estimates were calculated for an earlier version of the panels and Solar Roadways has been continuing to increase their output capabilities since.

There are various benefits to Solar Roadways serving as a decentralized power grid. Right now, disruption—natural or man-made—of a crucial power grid, plant, large transformer, or transformer yard can cause entire cities (or more) to lose power. Those critical vulnerable points aren’t needed if Solar Roadways are implemented on a large enough scale.

Glass Roads

Solar Roadways had to figure out a road surface that would transmit enough light to the solar cells while being at least as functional as current road surfaces. This led them to use tempered glass, similar to bulletproof glass, as the surface of their panels. Glass is much harder than asphalt.

The texture used for SRPs was designed to provide optimal vehicle traction for highway use. This surface will allow a vehicle travelling 80 mph to stop in the required distance, even when wet. This tempered glass, covering a fully functional solar panel, was load tested and can withstand 250,000 pounds. The maximum weight of a truck on US roads is 80,000 pounds.

SRPs underwent significant testing to ensure that they could withstand all the hazards of current roads. They were submerged in water in environmental chambers and tested for days as temperatures were slowly cycled from -20°C to 40°C (-4°F to 104°F).

SRPs were submerged in water for five months and operated continuously the entire time.

Rolling load testing was done using a 9,500-pound heavy vehicle simulator. This rolled continuously over SRPs for three months, simulating fifteen years of heavy truck traffic. 

SRPs have also undergone shear testing and meet the requirements for heavy vehicle braking. They meet all traction requirements of concrete and asphalt roads. The hexagonal shape helps to distribute shear forces to surrounding panels.

Textures for parking lots, sidewalks, and bicycle trails have been produced to optimize cost and features for the desired application. SRPs have even been built with smoother surfaces with anti-glare coatings for park and playground applications.

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For more detailed information about the SRP viability as a road surface, here’s the study done by Marquette University.

What else can Solar Roadways do?

When completely re-conceptualizing what a road is and what it can do, what kinds of futuristic features could you think up? Better yet, what kinds of futuristic features could a team of engineers, inventors, and environmentalists think up? Read on.

Lighting

Why use paint that reflects light to draw road lines when you can just use light?

SRPs contain LEDs with light sensors that automatically adjust their brightness. They can also be adjusted manually to compensate for any specific requirements. SRPs can even be made with fewer solar cells to make room for more LEDs, if required.

The first small-scale uses of LEDs for road safety have already happened. In the UK, LED studs that replaced traditional reflective lane markers have reduced accidents in some areas by over 70%. Now imagine that instead of single LEDs in specific places, the entire road surface was LEDs. The options are endless.

For example, when lanes need to be shifted due to construction (actually, Solar Roadways eliminates most road construction, but that’s for later), an accident, or any other problem, someone on a maintenance crew or in a remote control center somewhere can just shift all the lines on the road to divert traffic around the problem.

One of the main features of the very first SRP prototype was to change the LEDs in response to pressure. This can light up crosswalks with pedestrians in them. It can signal a hazard on the road such as fallen trees, rocks, or even animals crossing the road, and notify drivers of the hazard long before they can see it.

Outside of roads, there are many other uses for infinitely configurable lighting. Imagine parks. Hopscotch, four square, wall ball, and other children’s games can be requested on demand. A basketball court can become a street hockey court with a push of a button or a tennis or volleyball court as long as someone hangs the net. Imagine your next street festival on an entirely programmable LED street. Just when you thought Mardi Gras or Carnival couldn’t get any more colorful.

Leaving the dazzling behind for the practical, parking lots would be completely revolutionized. New parking spots could be created if the lot gets above a certain capacity. Dedicated spots such as handicapped, expectant mother, or emergency services could be clearly marked and added or changed instantly. Here’s a video demonstration.

I can imagine a couple of emergency uses. The lane a quarter mile ahead of an ambulance could flash red and blue to let drivers know about the approaching ambulance in a much more obvious way than a siren, which is frequently drowned out by road noise or music. When emergency services are dispatched to a location, the closest curb or parking area could start flashing red to give people time to vacate the area and warn newcomers not to park there, improving the chances of emergency vehicles having the best access to those in distress.

What uses for LED surfaces can you think up?

Heating

Another exciting innovation of solar roadways is that during cold weather events, the surface of the panels can heat to just above freezing. This effectively melts snow and ice while minimizing the power requirement and ensuring that roads don’t become attractive heaters for wildlife.

This may seem like it would only matter to people in northern climates, but as much of the US found out earlier this year, sometimes rare things happen that aren’t planned for. 

Imagine never having to shovel your driveway. Imagine never having to wait for a snow plow to come plow your street so you can get to work on time or get the groceries your family needs. Imagine being able to go on your morning run in the winter without having to worry about slipping on ice because your local sidewalks or park paths are Solar Roadways.

Most of the real-world testing of Solar Roadways panels has been at the company’s headquarters and in Sandpoint, Idaho’s town square, which is about as far North as you can get in the contiguous United States. Their public installation of 30 SRPs was opened in October of 2015 and has been running continuously there for six winters.

Cable Corridor

I think the Cable Corridor is the subtly best feature of Solar Roadways. It’s not flashy like solar panels and LEDs, but it solves a few current problems that have always made me ask, “Why isn’t there a better way to do this?” 

Electricity and communications going to and from the SRPs require cabling. In order to have the capability to service that cabling without needing to pull the panels up and impact the usability of the road, Solar Roadways decided to run all the wires and other necessary hardware along the side of the road in what they call the Cable Corridor. 

Cable Corridors are big enough for workers to fit inside them, and we can put things in the Cable Corridors that are currently scattered and disorganized. Buried power and gas lines would no longer be at risk of people digging into them. All the ugly wires that we currently hang on poles in the sky could be run through Cable Corridors instead. Not only would our roads and neighborhoods be free of hideous tangles of black cables and decaying wood or industrial metal poles, but ice and falling branches and trees could no longer break them and cause power outages, and utility workers would no longer have to work at dangerous heights. This benefit speaks for itself.

Water

Another problem with our current roads is that of water. Most obviously, water is a driving hazard. Lots of water on streets causes flooding and even a little water can be dangerous— reducing traction and causing problems like hydroplaning. SRPs address this problem with small gaps between the panels that allow water to drain off of the road’s surface.

A less immediate, but ultimately larger problem with water on roads (and all non-permeable surfaces) is the environmental one. With current roads, water washes across them picking up all kinds of debris and chemicals on the surface. That water then disperses into the local environment, taking its newly acquired contaminants with it. It then gets into the water table, rivers, and oceans.

Cable Corridors solve this, too. Water that drops between the SRPs flows across the road base (see picture) into the Cable Corridors. It can then be contained and deliberately routed. It can be collected in tanks farther underground and then pumped anywhere, such as to a treatment facility. It can also be treated on site before being released back into the local environment. Cable Corridors can be connected to existing sewer systems where available. Neighborhoods can opt to rout this lightly treated water into their irrigation systems without having to clean it to the level of drinking water. The possibilities are again numerous and customizable to the local needs.

Modularity

The modularity of Solar Roadways is another great feature. SR panels have gotten lighter and smaller over the years. In the current iteration a single panel is just over four feet in diameter and weighs 70 pounds. This makes replacing one a single-person job that takes only a few minutes. During this time, the maintenance worker could temporarily adjust the road lines around the work site and alert drivers miles before the work using just a computer instead of a truck full of cones (which become more road hazards). Compare this with the current state of roads with potholes and repair crews and the level of inconvenience and costs when repairing them. Again, the benefit speaks for itself. Roads without potholes? Yes, please.

Communication

The intelligent communication capabilities of Solar Roadways has been mentioned in previous sections, but it deserves its own attention. We’ve seen how it could help with crosswalks, animal crossings, repairs, emergencies, and more. Imagine what it means for all roads to be able to communicate with each other. Most roads have some communication ability now. For example, intersections can sense when you arrive and change the traffic light to green for you if no one is coming down the cross street—but those sensors are only at the intersection. Solar Roadways have sensors everywhere.

Most cities have a traffic management office or division. They monitor traffic flow and manage traffic signals to mitigate slowdowns during high traffic times. Solar Roadways would give them a lot more to work with in terms of information they receive, automation of responses, and response options, because they can literally change the roads on the fly.

Solar roadways could have automated features that don’t need human intervention. Weight in a traffic lane that doesn’t move for a few minutes? Probably a broken down vehicle. Time to automatically reroute traffic around that lane. Why not alert emergency services while we’re at it in case the driver’s phone is dead?

How many times have you rolled to a stop on the highway because of a crash ahead and wished someone would’ve told you about it before that last exit two miles back? Civil engineers get paid a lot of money to invent ways to optimize traffic flow. Solar Roadways can do it with a few lines of code.

Even just the information can be useful. How many people use Google Maps data, which is collected from our phones, to tell them where the traffic is? Why not eliminate the middleman and restore some of our own privacy? Solar Roadways will have that data by measuring the traffic directly.

Besides how communications between SRPs might help drivers and city officials, they also help themselves. A panel that stops working in some way can communicate its failure, automatically notifying maintenance workers. Even if the communications system of a panel fails, the other panels can notify maintenance of that failure.

Again, there are so many possibilities for greater efficiency and function with SRPs.

Electric Vehicles

Combining the environmental goals of Solar Roadways with future-proofing ideas, Solar Roadways have implications for Electric Vehicles (EVs). First, there’s the obvious use of SRPs to charge EVs using current charging methods. Most EV chargers are in parking lots which, if converted to Solar Roadways, could directly supply those chargers (given appropriate storage) as opposed to drawing from the grid, as they currently do.

Even more intriguing is the future capability of induction charging. Many readers may be familiar with this technology. If you charge your phone by setting it on or close to something instead of plugging it in, that’s induction charging. It only works over very small distances. This technology may be developed to work for charging EVs. 

Most people thinking in this space are envisioning a new kind of EV charger that uses something embedded in a parking spot instead of requiring a plug, but a further evolution could be charging EVs while driving on a road. This is further in the future than any other features, but it is possible. Companies and organizations have already started testing induction charging of EVs while driving, and Solar Roadways has been in discussions with some of them. With our current roads, this would seem very impractical due to the need to completely change how roads are built. However, Solar Roadways is already doing that, so killing an extra bird with this stone would provide a more practical way of implementing the wireless charging technology.

This is a way of extending EV range that is separate from the technology in the cars themselves and would go a long way to accelerating the adoption of EVs.

Autonomous Vehicles

Autonomous Vehicles (AVs) seem to be the inevitable future of transportation. There are multiple AV technologies being worked on right now. Tesla’s cars passed three billion miles driven on autopilot in early 2020. It’s full self-driving software, which started being deployed to users on October 11th, 2021, relies on multiple cameras (among other sensors) and advanced Artificial Intelligence (AI) to interpret things like road lines, other cars, and stop lights. Other technologies rely on high-definition maps that tell an AV where it should be, down to the inch, in real time. There are a plethora of technologies involved in developing AVs, and usually, multiple technologies are put to use in the same vehicle, but they all have their weaknesses. Most of these help the AV respond to what it detects, but what if the AV could be told exactly what it needed to know?

As was covered in the communication section above, Solar Roadways have access to a lot of information and are able to transmit that information. Why not have AVs receive the information? The Solar Roadways can tell AVs that are driving on them everything they know about upcoming road conditions along the AV’s entire route. More information enables better decision-making by AIs, and information coming from Solar Roadways is going to be much easier for AIs to understand than things like 3D mapping of the world. This would be machine-to-machine communications, and the technology industry is very good at making that work, as opposed to making AIs understand the world, which is very challenging. 

When combined with advances in AV sensors and AI, and other new technologies like vehicle-to-vehicle communication, Solar Roadways can be part of our acceleration toward safer and more autonomous roads.

Where’s the Bad News?

You’ve been reading through all the great things Solar Roadways can do, but ​​of course, everything comes with downsides. The most obvious weakness of Solar Roadways is the cost of wide scale implementation. LED-lit, microprocessor-containing, multi-sensing, heavy-load-bearing solar panels are going to be way more expensive than asphalt. There’s no avoiding that. But there are a few things that help reduce this problem of cost.

Context

If you live in the US, you’ll recall that our government just passed a $1 trillion infrastructure bill. For the record, that’s $1,000,000,000,000. Solar Roadways hasn’t published estimates for what turning the entire US into Solar Roadways would cost, but we know we’re willing to spend huge amounts on infrastructure. Done strategically, in many smaller steps, this is not completely unfeasible. 

As a basis of comparison, the entire interstate highway system, which was a massive public works project in the 1950s, cost $500 million (in 2016 dollars) according to the American Society of Civil Engineers. They estimate that that cost has been paid back six times over in increased economic productivity.

In fact, in 2014, the White House concluded that:

The costs of inadequate infrastructure investment are exhibited all around us. Americans spend 5.5 billion hours in traffic each year, costing families more than $120 billion in extra fuel and lost time. American businesses pay $27 billion a year in extra freight transportation costs, increasing shipping delays and raising prices on everyday products.

So, not upgrading our roads carries its own costs which are hard to see but massive. With that context, how can Solar Roadways become reality, from a cost perspective?

Income Generation

Once Solar Roadways are in use, there are many opportunities for them to actively generate income to offset their costs. Obviously, the power generated by the roads themselves has value. Private installations of Solar Roadways can range from an individual driveway, to the streets of a neighborhood controlled by an association, to the parking lot of a mall. All of this solar power will reduce energy costs for their owners, just like traditional solar panels, and can potentially be sold to the local utility company.

As we touched on earlier, Cable Corridors are a great resource. Their use could be leased to the local power company to put their lines that are buried or on poles in the much safer and more accessible Cable Corridors. The same goes for telecommunication companies, gas companies, and anyone else who wants to run infrastructure lines. These companies should be happy to pay a fee for this, since it will reduce their outages, maintenance costs, material costs (since they no longer need to replace poles regularly), and risk to their maintenance personnel. The same could be true for local wastewater utilities that make use of the water management features of Cable Corridors.

Another way of generating income is by selling advertising. Privately-owned Solar Roadways installations, such as the aforementioned mall parking lot, could sell advertising space using their LED capabilities. Businesses in the mall could broadcast their name and logo in lights in their parking area or direct people to their location with branded arrows on the other side of the mall. 

Savings

Besides actively generating income, Solar Roadways could represent a lot of savings that help justify their cost. As mentioned previously, road maintenance would be minimized, along with all its associated frustration and disruption (not to mention how many new tires I’ve had to buy because of poor road conditions). If entire towns decide to install Solar Roadways as public infrastructure, solar power would become the standard supplier for that town, which should drastically reduce electricity costs for everyone. In this way, Solar Roadways will pay for themselves with savings over time.

In cold climates, snow plowing, salting, and lost revenue from road closures would vanish. The budgets for those things could be reclaimed for other uses. The costs incurred by everyone during a power outages would also vanish if power was generated by Solar Roadways and/or distributed through Cable Corridors. 

Finally, as with all technology, the cost comes down over time. More iterations of Solar Roadways’ SRPs will make them more affordable, just like standard solar panels, until they can be cheaply incorporated into anything.

Conclusion

Solar Roadways represent the ingenuity of the American spirit in the modern age—to solve problems and think up new and better ways of doing everyday things.

As with all futuristic inventions with great potential, Solar Roadways comes with some known downsides, and may even come with unexpected consequences we have yet to see. It makes sense with innovations of this sort to try it on a small scale, learn from it, iterate, and expand. This has been the process that Solar Roadways has been undergoing since its inception, and I, for one, am looking forward to seeing how this story continues to unfold.

What do you think? Are solar roadways a viable alternative to our current roads? Are they the best option? Are they worth the cost? Leave us a comment below.

To learn more about Solar Roadways, check out their website and follow them on Facebook, Instagram, and Twitter.

You can sign up for their newsletter to get updates by emailing Newsletter@SolarRoadways.com. 

Editor: Stacia Wilson
Peer Review Completed By 4 Individuals