By Niek Veraart, AICP, David Reel, and Alicia McConnell, PE, SUAS
Drones can be traced to as early as 1849, when they were used in war as balloon carriers for bombs dropped with the aid of a time fuse. They have evolved into sophisticated devices with a range of applications, including inspection, agriculture, retail, search and rescue, and urban and community planning. In particular, drones (called unmanned aerial vehicles by the Federal Aviation Administration, though "uncrewed" is a more inclusive term) are opening new avenues in transportation, particularly as a tool for visual storytelling, monitoring, and data collection.
But it's not just about drones. Drones are part of larger networks called Unmanned Aerial Systems (UAS), which not only include the vehicles but also the controllers, sensors, GPS, and radio components that work together to complete the mission. UAS make it possible to collect vast amounts of data cost effectively and turn that data into valuable information that ultimately supports more intelligent, more informed, and more inclusive planning.
The value proposition
As we all know, the best transportation plans involve a comprehensive review of all possible strategies. This allows for an evaluation process that encompasses diverse stakeholder viewpoints and input from transportation agencies, businesses, community organizations, environmental groups, and the general public — all before any ground is broken. Research and data analysis are vitally important to this planning process. This is one area where UAS offer significant value to transportation planners. The aerial imagery, high-resolution video, and refined data captured by drones offers new vantage points and information previously not available, allowing users to document congestion patterns and hot spots, as well as surrounding land uses, sites that are difficult to access on foot, and transportation rights-of-way.
UAS provide a more global perspective of a project site than mapping and environmental assessments typically performed by on-the-ground specialists. Drones allow entire corridors and sites to be documented from multiple vantage points and elevations. By understanding the systemic interrelation of issues — even those not yet identified — planners can better predict issues that may arise and identify trends, like erosion, drainage issues, and wildlife habitats and behavioral patterns.
In addition to capturing static images and video, UAS can be used to create 360-degree images, develop virtual 3-D models, and visualize what a completed project will look like by overlaying renderings onto aerial images. This all leads to telling a better "story" of the possibilities for a project (as well as its impacts), not only showing what a project will look like, but also how it will function. This is especially relevant in transportation applications, which greatly benefit from the ability to show movement of different modes and access points. This modeling helps planners plan, yes, but also can help others visualize projects, including the public, key stakeholders, and agencies responsible for approvals.
Because UAS collect large amounts of data in a fraction of time it might take using traditional methods, they can also save money and reduce staff time. By shortening project timelines and costs, UAS can also open up possibilities to explore and communicate multiple project options and funding scenarios.
UAS can be incorporated into transportation planning in a number of ways.
TRAFFIC SAFETY PLANNING. Transportation planning has evolved from solely considering infrastructure options to more broadly meeting the needs of the traveling public, providing management and operations, and improving transportation system performance. When planning improvements for existing corridors, collection of accurate, precise information about traffic patterns and road conditions is critical to making informed recommendations. Traditionally, a department of transportation would monitor traffic through tower-mounted cameras and embedded detectors. Lesser traveled routes or intersections might require a manual count.
With drones, however, real-time observations of traffic flow and conditions during peak-hour conditions can help planners make changes to improve driver, biker, pedestrian, and public transit rider safety. The modeling informed by analyzing drone footage and data allows planners to make modifications within a simulation and replay the potential effects of each option. Artificial intelligence and machine learning (see "The Art of Learning by Example," Planning, October 2020) can help even further by analyzing the video data of a wide range of conditions and different locations. These technologies can then correlate video with safety and efficiency criteria to create optimal, cost-effective solutions.
UAS can also play a significant role in planning and designing maintenance of traffic plans during construction of transportation projects. Equipped with real-time traffic impact updates, adjustments can quickly be made to keep drivers moving through the project as efficiently as possible to reduce backups.
Finally, UAS can be used to plan for parking. In 2019, the urban big data start-up Quantifly used UAS as part of a parking study of Detroit's 200-acre recreational East Riverfront area, which included 6,800 parking spaces. The study, led by Nelson/Nygaard for the Detroit Economic Growth Corporation (DEGC), was conducted in two phases: The first was a typical Saturday along the riverfront, with 12,782 cars counted over 11 hours. The second was conducted to measure the impact of a large concert on the riverfront's on- and off-street parking supply, with 9,412 cars counted over a three-hour period.
The raw aerial imagery was translated into orthomosaics (composite images made by stitching together hundreds of smaller images taken by drones and then corrected for distortion). Next, a proprietary algorithm calculated the parking occupancy of the study area. The output data included high resolution orthomosaic JPEGs; georeferenced GIS shapefiles; Microsoft Excel files of every car counted by lot, block, time, and date; and graphs of hourly parking occupancy to capacity counts.
Given the scale of this study, it would have been difficult to efficiently conduct a traditional "license plate" parking occupancy study. By using drones, Quantifly captured hourly aerial imagery of all the cars, so if the city would want a parking turnover study at a later date, the original orthomosaics could be used to gather this information, rather than conducting a second study.
“The resulting data is amazingly rich and precisely accurate. This data gave the study team an irrefutable set of facts — the data is backed up with snapshots of the parking areas being measured, so that it can be visually verified if doubts arise — to move the conversation beyond a narrow focus on supply-driven solutions. Without invalidating the important benefits of some viable options for expanding supply, this data put a measurable emphasis on just how much there was to gain from simply managing existing parking better,” says Nelson/Nygaard principal Thomas Brown.
The aerial imagery also gave DEGC a valuable visual presentation tool to make the case to elected officials, residents, and business owners.
RESILIENCE PLANNING. UAS can be a major tool in strengthening a community's resilience before and after a disaster strikes. Risk assessments can be performed in real time to help leaders better identify and assess potential hazards and generate up-todate maps quickly. That allows planners and others to coordinate response efforts, identify areas that may be more prone to damage, flag critical infrastructure, and pinpoint early warning signs before a potentially destructive event. After an event, UAS can be deployed to monitor evacuation conditions, identify affected roadways, and provide public safety information. It can also quantify debris and identify it by type to optimize its removal — including how to access it safely. This information can also help in the longer term as planners make recommendations for new or improved transportation infrastructure.
In January 2017, an emergency task order was issued by the Nevada Department of Transportation in response to major flooding of roads and highways along Pyramid Lake. Low cloud cover and hazardous conditions made it unsafe to deploy ground crews, so our firm deployed UAS to capture imagery and surface data for the entire 15-mile section of washed-out highway. This allowed transportation planners and engineers to plan for filling the gap and the duration of highway closure for repair. The planning team also used the data to predict future erosion, which allowed for strategic placement of culverts prior to adding in the fill.
ASSET MANAGEMENT. In the initial planning stages, drones can help planners be smarter about thinking through the entire life cycle of a project, avoiding overdesigning projects, saving costs, and reducing timelines — which, in light of budget challenges caused by the pandemic, will be more crucial than ever.
Once a highway or bridge has been planned, designed, and constructed, drones can help manage those assets. Proactive inspection and monitoring allows planners to identify potential issues before they become larger problems that necessitate costly repairs and replacements, asset downtime, and exposure to safety risks. This can lengthen life cycles, which, in turn, can delay replacement and new capital expenditures. Bridge planning and inspections in particular can benefit from the UAS data and aerial imagery that supplement traditional hands-on rope inspections. In these instances, efficiencies of 50 to 75 percent can be achieved based on historic data.
SURVEYING AND ROUTE PLANNING. Drones can carry out topographic surveys for new routes or alterations to an existing corridor with similar accuracy to measurements collected by traditional methods, but in significantly less time. Pairing UAS with a survey crew allows surveyors to set and collect fewer shots, or just enough to verify post-processed UAS data. It can be as straightforward as using drones to simulate and confirm the proper topographic location and height at which to install traffic cameras to ensure complete 360-degree visuals. Or it can be more complex, such as the approach our firm took last year when performing construction site inspection and monitoring flights for the Connecticut Department of Transportation's Middletown Bridge construction.
Using a high-resolution camera and aerial targets with coordinate information, we created a 3-D surface model of the project area at different stages of construction. In this case, the images and elevation data allowed us to review the existing topography of the site, compare the surfaces to preconstruction conditions as well as previous stages, and confirm quantities and volume calculations.
Our UAS team provided the surveyor with ideal locations for ground control, coordinated with the surveyor on site, and developed a plan to ensure appropriate ground sampling distance was achieved. They also postprocessed the data to develop an orthomosaic image, digital surface model, and volume calculations, and verify quantities between each stage of construction. The surface models allowed designers to calculate volume differences and verify fill quantities between each stage of construction, thereby increasing the efficiency of planning and construction, and safety, and minimizing impacts.
One interesting use of UAS is the notion of "dynamic planning and design," when a situation or process is observed and recorded and used as input into the planning and design process, including public engagement. For example, so-called "pedestrian desire paths" recorded by UAS can help urban designers understand how people move within a space to determine how to design or adapt pedestrian pathways, complementing existing modeling techniques based on empirical data and algorithms.
ENVIRONMENTAL PLANNING. A key consideration in any transportation planning project — from clearing brush and trees for a new highway to constructing a bridge over a stream bed or wetland habitat — is environmental impact. Often, agencies can only account for what they can see on foot. Drones provide different perspectives and a more complete picture, which can streamline the environmental assessment process and lead to more effective mitigation measures.
Key issues in environmental planning and environmental review are traffic impacts (including safety) and congestion, often involving extensive modeling and mitigation measures, which can have their own environmental impacts. UAS can collect data to better understand traffic flow and interaction among different transportation modes under existing and future conditions. Furthermore, once the project is completed, UAS can be used to monitor transportation movements and ensure that the mitigation is effective, as well as make adjustments when the mitigation implementation can be improved.
Drones are increasingly used in combination with traffic patrol vehicles to monitor and manage congestion and traffic incidents. In Seattle and Los Angeles, drone patrols have been integrated into traffic management and law enforcement activities. In China, drones have been used to monitor and manage traffic during national holidays, and a drone force has been integrated in the police services of Devon, Cornwall, and Dorset in the UK, with capabilities of traffic monitoring and incident management.
Post-incident, a drone can collect imagery for a visual snapshot of the scene and, if equipped with the right sensors, also collect infrared imagery of the scene to determine where a vehicle may have first started to skid off the road. These thermal signatures can tell inspectors a lot about a crash scene that may not be immediately obvious.
As our transportation infrastructure becomes "smarter" through new wireless communication technologies (both between vehicles and infrastructure) and increases in computing power and energy efficiency, congestion impacts can be preemptively mitigated. This effectively increases capacity, improves safety, and reduces environmental impacts.
An interesting application of this concept that combines a transit vehicle with drone delivery is being explored by Stanford's Intelligent Systems Laboratory and Autonomous Systems Lab. It involves mounting a drone on a transit vehicle that is already circulating, which allows the drone to deliver packages and collect information within a relatively small radius. This application has the potential to reduce congestion and improve traffic safety and air quality, especially on local and residential streets.
The Federal Aviation Administration (FAA) has recognized that UAS are the fastest growing segment of aviation in the U.S. and has initiatives underway to fully integrate the innovative technology into the national airspace. The UAS Integration Pilot Program (IPP) was established in 2017 and brings state, local, and tribal governments together with the private-sector stakeholders (drone operators and manufacturers) to help the U.S. Department of Transportation and the FAA craft new rules, policies, and guidance that specifically address UAS use. The IPP reinforces the significant opportunities that UAS present to planning, engineering, and other services. In May 2018, 10 participants — including the city of San Diego, the North Carolina Department of Transportation, the University of Alaska- Fairbanks, and the Choctaw Nation of Oklahoma — were selected to collect drone data over two and a half years. When the pilot wraps up, the data collected from these operations will help the USDOT and FAA establish new rules for more complex low-altitude operations, identify ways to balance interests related to UAS integration on local and national levels, improve communications with key stakeholders, address security and privacy risks, and accelerate operational approvals.
However, it's important not to let the buzz around drone technology overshadow or displace tested traditional methods. Indeed, the combination of new technologies and established practices often leads to the greatest innovation. UAS are not replacing traditional surveying, Lidar remote sensing, and in-person assessments; rather, they are supplementing them and enhancing the data and information available to make the best, most informed planning decisions. There are certain scenarios where UAS thrive, yet others — like mapping large expanses with drastic elevation changes — where traditional aircraft are a better solution. However, data collected by traditional methods can be linked to drone datasets, combining qualitative data with quantitative data.
Planners need to assess the project and determine a solution that combines the right technology with our traditional methods of data collection to complete their project goals. This hybrid approach aims to identify the correct mix of methodologies to achieve the desired product — a transportation plan that safely and efficiently moves people and goods to their desired destinations.
The authors work at Michael Baker International, where Niek Veraart is senior vice president and national practice lead for planning, David Reel is vice president and west region practice lead for planning, and Alicia McConnell is the UAS program manager.
Using Drones in Planning Practice: The applications for unmanned aerial systems are substantial and growing. The information and guidance in PAS Report 597 are intended to provide planners with the knowledge they need to determine whether UAS can enhance their planning practice, and how to make drones a tool that all practitioners know when and how to use.