Category: Technology

Traffic Modeling 101: Using Traffic Modeling Software to Improve Mobility

Traffic model snip showing intersection and cars

What it is

Traffic modeling takes raw data (in the form of traffic counts and speed data) and builds a visual representation. This visual representation allows us to see how things interact with each other, which can be as simple as a stop-controlled intersection or as complicated as an entire city grid. The modeling allows us to look at how intersections perform in terms of level of service, traffic delay, and capacity utilized among other metrics.

Traffic modeling doesn’t just show how cars move in a straight line on a road. Instead, the modeling shows how traffic might back up at an intersection based on how much green (light) time each direction of traffic is given, how side roads are affected by long lines of vehicles, and what is happening at turn lanes. We also include pedestrians when there’s significant data for them; at small, rural intersections, there is not enough demand to show them in the model.

The level of service is the key metric for analyzing how well a signal functions. Level of service is categorized by five letter grades (A through F), but it’s really just an incremental delay in seconds. For example, if the average driver is stuck at a traffic light for less than 10 seconds, that’s level of service A. If it’s over 10 but less than 20, that’s level of service B, and so on. So really, the level of service is just a way to say this is the range of delay that the average person gets at this intersection. It’s key that it’s the average driver; so the first person who pulls up to a red light is likely going to be sitting there for more of the full signal cycle, but someone that arrives on green had a zero second delay – that’s why it’s key to measure the average.

Why it’s useful

I’ve been using the modeling software since I started here in 2013. It was pretty basic for the first few years, really just using it to model temporary signals; like if we had to go to a one-lane work zone with alternating directions of traffic, we’d use a temporary signal for that and need to model it to make sure the queues didn’t cause any big problems. In terms of how traffic modeling differs from pure calculations, it really has to do with its scale. You know, you can input some parameters into the software, and it runs all the iterations you need and can simulate random traffic patterns that a calculation wouldn’t be able to do. It also helps give you a visual representation of it. I could do a calculation that says, okay there’s a 300-foot queue here, but then when we put it in the modeling software, we can see that the queue is actually blocking a side road or spilling into the next traffic signal.

The flexibility to play around in the software is also significant. With a calculation, if you want to change something, you more or less have to restart the calc; but in the model, you can toggle a switch and it just completely changed your model – and you can change it back if you need to.

Our standard traffic modeling program is Synchro which is the static model, and then we also have SimTraffic which creates a video simulation of cars moving through the model. The video is the simulation of when the system is populated – that’s what uses the random traffic patterns, which is helpful because there is no calculation for random traffic patterns. You need to have the computer algorithm that best approximates random traffic driving patterns. With that simulation, you get to see how signals interact with each other; so you have one signal, and then you have another one 300 feet away; they might not be coordinated, but they will still influence the traffic patterns at each other, and it’s crucial to see what sort of problems they may cause.

What the challenges are

There are only minor downsides to traffic modeling software. There are so many different parameters in the programs that you might get a totally different result if you overlook one that’s buried deep in the dialogue boxes. In terms of reporting, there are also several different analysis methods you can get from the program. The simulation doesn’t change, but I can have the same traffic volumes and signal timing and still get three slightly different results based on the analysis method. There’s no significant difference, but depending on what the client or agency expects when they review it, it can impact the program’s options.

A good example is New Hampshire Department of Transportation (NHDOT) has published preferences for their report formats, but many clients do not have preferences, and so the lack of standardization can be a challenge.

Where it’s headed in the future

In the future, we will be using traffic modeling software more often. The developers of the traffic modeling software are continuously working on and releasing updates for the programs. We as designers are constantly trying to come up with new ways for traffic signals to be safer or to handle higher capacity. Sometimes, the software doesn’t have the availability to model those correctly because it’s a new innovation that hasn’t made it back into the software yet. So sometimes these updates are just the software catching up to what’s actually being in done in the field.

I expect there will also be some improved bicycle and pedestrian modeling capabilities. Right now, we can say there’s X number of bicycles per hour, but I envision software developers will be adding bicycle signal heads next to traffic lights because that’s an up-and-coming technology. It’s been tested in a couple of states already, and it could become an important part of traffic modeling software updates in the near future.

I’m part of a team that prepares traffic modeling projects for municipalities and state agencies across New England. Reach out to me with traffic questions or to learn more about NHITE.

Part 2: Six Programs that Contribute to a 2D Hydraulic Model & Why They Matter

Hydraulic modeling software image with arrows and blue green and orange colors showing water movement

We introduced 2D hydraulic modeling and its purpose in Part I as a way to calculate how water moves and why we use the modeling to help us engineer better bridges. With that understanding, we can further explain the different ways we get the data to make those 2D models work.

The math and programming are not simple, so using simplified terms, we will break down six common programs and types of data to show how it all comes together.

#1: Google Earth

Google Earth: Many people know Google Earth as a fun tool to see their house or maybe where they want to vacation either in an aerial or street view. Engineers use Google Earth not only to see existing conditions, but also to see the aerial history of a location, as Google has images of the land as it has changed over time. For example, we can use Google Earth to look at a river 20 years ago and see how that same location has changed over that period! Is it wider because the banks are eroding? Has it meandered, causing our bridge to need re-alignment to better fit the path it has taken? Has it taken a shortcut and cutoff any oxbows (or U-shaped bends in the river) over time?

Google Earth graphic showing how the land can change over time. This image shows oxbows cut off over time (change of 22 years shown from 1996 to 2018).

The aerial images also provide information as to the roughness (think texture) or the topography. When the river floods, will the water pass quickly over the smooth fields, or will it slow down because it has to travel through a dense forest with brush scattered over the forest floor? We apply a Manning’s roughness coefficient, n, to this area in the water modeling software to help it figure out where the water wants to move. The street view can help show what the surrounding area is like from the ground to give a better idea of what the roughness should be. Sometimes it is challenging to determine how dense a forest is from the aerial view, but the street view could show if the forest floor is clean with few branches at water level, or if there’s a lot of low branches and additional brush that will slow the water down in the event of a flood.

#2: StreamStats

StreamStats: StreamStats is a web-based geographic information system (GIS) application for water-resources planning that we use to delineate watersheds and determine flow (or how much water is passing through a section). This application uses gage data of existing streams and known flows with regression equations to determine the flood flows at a location without a gage. Now first off, you might be asking yourself “what the heck is a gage?” A streamgage uses instruments to measure and record how much water is flowing in a stream at a particular location. You can learn more about it on the US Geological Survey (USGS) website. Secondly, you might be thinking “what is a regression equation?” This is a type of equation used in statistics to determine a parameter (e.g. flow) based on the relationship between sets of data like watershed size and storage. Essentially, the equations use the information from streams with gages to extrapolate what the flow most likely is at an ungaged site. You can click on a stream point (as long as it’s inside applicable limits) and the program will then delineate the watershed and tell you what your flow is! But as is true with most software, you need to check what it gives you to make sure the delineated watershed is accurate, and the flows are reasonable.

#3: Mathcad

Mathcad: We use Mathcad to perform calculations. For example, New Hampshire requires engineers to complete hydrology calculations for bridge designs; alternative methods to determine the flood flows at the bridge are done to check that the flows determined by StreamStats are reasonable. Again, it’s not as straightforward as “StreamStats is giving me this data, let’s use it,” it needs to be checked! Mathcad allows us to efficiently check the flows from StreamStats by using other methods (i.e. equations). Mathcad is also commonly used to calculate the scour depths around the bridge foundations and size the riprap protection mentioned in Part I.

#4: LiDAR

LiDAR: We also use LiDAR data. While not a specific program, LiDAR gives us images from ground penetrating radar so that we can bring these images into a hydraulic model to merge with survey data. From this information, we can get a fairly accurate account of land to model. LiDAR will reflect things like a knoll in a plane underwater, but it won’t show the water itself; it will show why the water is moving around something we can’t see without this data.

#5: SMS

Surface-water Modeling Solution: More commonly known as SMS, this program is the graphical user interface developed by Aquaveo; this is the software that we use to put together all of the data to create a model that can showcase contours and streamlines representing water. We use the aerial image from Google Earth in the program to define the various areas of terrain roughness; use the flows from StreamStats to tell the program how much water it needs to include; and use the LiDAR to define the topography throughout the model. SMS is especially useful when we are explaining to clients the need for different types of infrastructure or to show the public what’s going on with the water, but it’s also useful for the engineers to be able to see the reason we would need different foundations for a bridge or different materials to construct with because of water flow. For example, although the bridge may span the bankfull width, is the bridge still a constriction in the overall floodplain that could cause deep scour? Or is there an area of the roadway that is still overtopping and might experience erosion?

#6: SRH-2D

Sedimentation and River Hydraulics – Two-Dimensional model: This program is known as SRH-2D and was developed at the US Bureau of Reclamation in collaboration with the Federal Highway Administration and the Water Resources Agency in Taiwan. This is the software that deals with the computational efforts that go on behind the scenes after the model is built in SMS. It’s a 2D hydraulic, sediment, temperature and vegetation model for river systems. SMS and SRH-2D usually confuse people because they think they are the same, but you use each of them for different purposes: SMS is for setup and reviewing results, and SRH-2D is for processing for the information.

There are some programs we haven’t talked about here. For simple culverts, the HY-8 Culvert Analysis Program developed by the Federal Highway Administration may be used. SRH-2D can utilize HY-8 to incorporate culverts within the 2D model; this development of SRH-2D was in cooperation with Aquaveo and the Environmental Modeling Research Laboratory at Brigham Young University. For 1D hydraulic modeling we would use the Hydrologic Engineering Center’s River Analysis System (HEC-RAS) developed by the US Army Corps of Engineers – which can be used for 2D but is not as widely used as SMS, especially in the Northeast. We could also use 3D hydraulic modeling technology, such as FLOW-3D, but that will be more prevalent in the future when computational power can better handle the programs required for it.

Computers have come a long way in being able to process the complicated software to create 2D hydraulic models. While 1D hydraulic modeling gave us more capabilities with bridge hydraulics than just calculators, we are pleased with the extra capabilities 2D hydraulic modeling has afforded us and are always looking for ways to use it better. Want to find out more about 2D hydraulic modeling?

Part 1: Why & How 2D Hydraulic Modeling is Enhancing Bridge Engineering

Image of colorful 2D hydraulic modeling image with arrows indicating which way water flows

A bridge, culvert, the road nearby or above, the banks, and the surrounding ecosystem are affected by water’s flow. It is no surprise, then, that studying hydraulics and hydrology when designing bridges is paramount for safety, road users, and engineers.

The purpose of hydrology is to study water itself with respect to the land, whereas hydraulics studies what the water is doing within a channel or pipe. So, when engineers develop 2D hydraulic models, they are looking at how water behaves in a given area, and ultimately use that information to build safer bridges. This type of modeling tells engineers not only where the water is going, but where it wants to be.

Basically, 2D modeling determines and depicts water flowing back and forth (on a horizontal plane) instead of horizontally and vertically (3D modeling). The modeling is presented as a dynamic graphic that shows the flow of the river or water body. With a bridge in the model, engineers can determine how the water will move around piers and abutments (the bridge foundation), what could happen with scour and decide how to design for it, and predict the bridge’s impact on the environment (and the environment’s impact on the bridge) for years to come.

2D hydraulic image of black water on a map with white, moving lines showing water flow direction
2D hydraulic model

First things First

When a bridge engineer designs a bridge or culvert associated with water, hydraulic modeling isn’t an afterthought; it’s one of the first things that gets done when a project starts. Structural engineers already have data about the area and usually the existing bridge. Still, they often need more specific information to understand the entire project better – for example, data points on the lowest part of the bridge and how the structure is situated in relation to the water below.

2D hydraulic modeling at the beginning of the project gathers that information and helps the engineers better plan for the project, and is welcomed by this engineer as a preferred alternative to the conventional 1D modeling. It’s not just a benefit to engineers who want to know a system’s details, though. Clients, municipalities, and everyday citizens benefit from engineers using 2D hydraulic modeling – because it helps convey to them what’s happening with the water and helps the engineers better protect the infrastructure we use every day.

When it Rains, it Pours

When you think back to the Mother’s Day floods in 2006 or any other time flooding threatened New England, you probably don’t think much about the bridges you drive unless the water pools over the road. What few people think about is what’s happening under and over the bridge; with faster rushing waters and more force, there’s the potential for three big events: scour, rising water carrying debris, and pressure on the bridge caused by flooding water.

Scour is what happens when sediment around the bridge foundation (or along the roadway) erodes and starts washing downstream, leaving the potential for the material under the bridge to become unstable. In some cases, sediment from upstream of the bridge will wash downstream and fill in these holes during the storm before anyone realizes how big of a scour hole actually developed. We use 2D hydraulic modeling to help better predict the scour that might occur during these events even though we may not see it.

Image of a flooding truss bridge in Ludlow, VT during a large storm

This erosion can also occur beside and/or below the roadways leading up to the bridge if the water flows over the roadway. The 2D model enables us to see how much of the water is going over the roadway as well as provides us with the depth and velocity of this water. We can use this information to determine if the sides of the roadway might be in danger of washing away with the water. If the embankments might erode, we can properly armor them and keep them protected.

Part of our job is looking out for this erosion – if we determine that scour might be a potential issue during a storm, we can get ahead of it. One way of doing this to help prevent it under the bridge is by putting riprap (larger stones) in front of and around the bridge foundation to help keep the natural, finer sediment of the streambed and below the foundation in place. Another way is potentially changing the foundation type: if the anticipated scour is deep, we might change from a shallow foundation to a deep foundation. Scour is just one of the dangers associated with large storms, and 2D hydraulic modeling gives engineers the insight they need to help prevent dangerous situations.

Rising water is another danger to bridges, not just because it could potentially overtop (flow over) the bridge, but because the rushing waters can carry debris (say, a fallen tree) that could hit the bridge and cause damage. When we plug in potential flooding scenarios into the 2D hydraulic models, we use the models to predict how high the water could potentially get during a storm. That way, we can plan to build a new bridge or raise an existing bridge above the water level, reducing the chance for the bridge to be damaged.

2D hydraulic image showing velocity and water flooding on top of bridge

The third big concern with large storms is the power of flooding waters pushing on the bridge. This pressure could be going into and on top of the bridge, but also could come from under the bridge (buoyant forces trying to lift the bridge up). For this scenario, 2D hydraulic modeling allows us to see where the water would want to go during a flood and determine how much of it is going under the bridge, over the bridge, and around the bridge. This allows us to evaluate what an existing bridge might experience, and to design a new bridge to eliminate these forces (locate the deck above the water) and to resist the forces that can’t be eliminated for a certain storm event.

Garbage in, Garbage Out

The more data we can put into the model and the more accurate that data is, the more confident we can be with the results. That means that for the most part, 2D hydraulic modeling provides valuable information that we had to assume or make educated guesses about 30 years ago. While 2D hydraulic modeling doesn’t solve every problem, it gets us closer to understanding the hydraulics of the bridge. In the event that a solution doesn’t quite make sense, it could be because we need more or better data to put into the 2D hydraulic model.

For example, we’re working on a project right now that is analyzing an existing bridge in a river. Using 2D hydraulic modeling, we noticed that the water isn’t flowing as expected. We looked upstream and noticed old bridge abutments causing a constriction in the water flow. This slight constriction causing the river to backwater and holding part of the flow back is a great example of how limited data can affect the hydraulic modeling, or what I like to call “garbage in, garbage out.” If we didn’t have the data that depicted this constriction, we might have missed how it influences the river and the flow at our crossing.

Another project currently underway involves an upgrade and analysis of two culverts, with a third culvert right upstream, that have all been causing water constriction. The 2D hydraulic model shows us how these constrictions are causing backwater and increased flooding. The 2D hydraulic analysis also allows us to see what happens when we change the structures in the water. With some tweaks to the 2D model, we’re able to see that if we replace the two downstream culverts with a wide open structure that spans the bankfull width, the flooding is significantly reduced in the model. Meaning that if we replace these culverts with this other bridge system we designed, the next huge rainstorm won’t cause so much issue.

Want to know more about 2D hydraulic modeling?

We’re only as good as our data and our engineers’ analysis of that data. 2D hydraulic modeling has helped us foresee challenges to certain bridge structures while advocating for others to serve an area better. It replaces 1D hydraulic modeling at a time when computers now have the bandwidth to handle the massive programs required to use.

If you have any further questions, reach out to me and stay tuned for the follow-up blog on the different programs and math needed for this undertaking!

What you May not Have Considered about Solar Energy in New England

Hoyle, Tanner is currently providing professional engineering design services for the development of solar energy in New England. We are working for several solar companies as the solar industry has not only taken off in the flatlands of our Midwest United States, but solar energy development is also happening in our New England backyards.

There are many reasons why this industry has recently become so popular. Solar energy has become a viable option because of the sun’s power – but also because of its cost. As the technology of solar energy has become more efficient, the option for purchasing solar power has become a reality to an average energy user.

In order to consider solar options, permitting and procurement need to be considered.


Public utilities commissions and state regulators have recently developed and revised rules and regulations for the advancement of solar energy. Hoyle, Tanner has stayed up-to-date with the development of these guidelines so that we can keep our clients educated and able to make sound decisions and reliable investments — not only based on costs, but also permitting success. The probability of getting a project permitted is a major milestone in the progression of a project, and can in many cases can determine if the project ever gets started.

There are many factors that contribute to the permitting and design of a solar array. Following is a list of some major factors that can affect development:

  • What is the size and shape of the property?
  • Is the property located in a properly zoned area or can it be rezoned?
  • Are the soils adequate to develop for this use? Are there significant wetlands? Are they well drained soils?
  • Is the topography adequate for solar development? Is the orientation of the property favorable for solar development?
  • Are there abutting structures on neighboring property that would prevent sunlight from reaching the site?
  • Is there adequate access to the property?
  • Is there access to an existing power source to transmit the power?
  • Are there natural resource protection areas within the site (vernal pools, deer wintering areas, or historic preservation areas)?
  • Does the developer have adequate title to the property?

Hoyle, Tanner has developed several solar array sites being cognizant of all the factors pertaining to a successfully designed and permitted project, while keeping versed of the regulatory processes. With our experience, we can save the client time and money while helping them realize a successful project.


In many state governments, there is a procurement process for renewable energy projects (that are part of energy packages). These packages contain guidelines for the development of a limited amount of energy. What we are finding in some states is the need to increase the development limits as demand increases. Hoyle, Tanner is working with state agencies to make sure we are aware of these opportunities so that we may share them with our clients.

In some states there is a procurement process, raising the net metering cap, allowing arrays of up to 5MW — 5,000 KW — to sell or store excess energy. 

Raising the cap is what makes renewable energy development viable for investors, developers, and municipalities. These opportunities to create renewable energy not only lower the states’ dependence on fossil fuels to generate electricity but are also expected to create new jobs in the coming years as the number of projects increase.

Many states look to increase their renewable energy portfolio standard — the amount of renewable electricity created as opposed to that created by fossil fuels — from lows currently at 10% or less to 40% or 80% by 2030 and some even at 100% by 2050.

Helping Developers

We understand the importance of this type of development and the need for development of renewable resources. Our design experience helps the developers understand the limitations of development and of course the permitting process.

Hoyle, Tanner’s experts are here to help. If you have any solar development questions, contact Andy Sturgeon, Vice President and Regional Business Manager.

How Hoyle, Tanner is Saving Time and Money with Drone Flights

Clearing the air! This is what our small Unmanned Aircraft Systems (sUAS – commonly referred to as drones), operators Evan McDougal, CM and Patrick Sharrow, AAE are incorporating into airspace analysis. Evan and Patrick are just two of Hoyle, Tanner’s professional Part 107 remote pilots who are utilizing photogrammetry and advanced autonomous sUAS technology to analyze and access airspace obstructions. With recent media highlighting the challenges of integrating sUAS operations into the National Airspace System, it is an exciting time to focus on the safer, less expensive, and expedient capabilities that these vehicles make possible.

Many organizations, both private and government, are interested in what these small flying sensor system platforms can do. For instance, many state aeronautics agencies that oversee the safety and operation of multiple airports can spend weeks with multiple survey teams and inspectors traveling from airport to airport assessing tree canopy and surrounding buildings – all in an effort to determine if there are obstructions to FAA approach and departure surfaces and pilots utilizing the runway.

In contrast, a drone can be flown by a trained and qualified pilot to collect accurate obstruction data. The three-dimensional results can show the entire area in many formats in a fraction of the time and cost it would take a ground survey crew or aerial survey.

Hoyle, Tanner is passionate about increasing safety and efficiency in aviation. During the September 2018 National Association of State Aviation Officials (NASAO) Annual conference in Oklahoma, Evan McDougal demonstrated his enthusiasm for the emerging technology and the airspace analysis applications we have developed.

Evan showed interested State Aeronautics Department Representatives how they could benefit using sUAS systems for obstruction analysis. Bryan Budds, Transport and Safety Section Manager at the Michigan Department of Transportation (MDOT), was quick to recognize the benefits of this capability and the opportunity to advance the MDOT existing drone program. He arranged for Hoyle, Tanner to spend three days training DOT employees on how to collect accurate obstruction data using drones as well as process it into meaningful deliverables.

The information gathered in the sUAS flights is used to create detailed 3D models of the airport including trees, pavement condition, ground contour elevations, and surrounding land development. Once collected, the data can be used to graphically depict airspace approach corridors that are not able to be seen with the naked eye. Obstructions are clearly shown protruding into protected airspace making it much easier for the airport and responsible landowners to agree on obstruction removal alternatives.

With the proper coordination of sUAS data collection and software processing systems, “clearing the air” can be done economically, accurately, and efficiently. The exciting reality of the sUAS market is that the sky is the limit! Hoyle, Tanner is committed to continually evolving and developing new opportunities to increase safety and efficiency in aviation moving into the future.

Curious about how you could use drones on your next project? Contact our experts Patrick Sharrow, AAE, or Evan McDougal, CM

The Flow of the River: What 2D Hydraulic Modeling Can Teach us about Movement

GIF image of 2D hydraulic modeling showing water under a bridge

Imagine trying to measure water in a beaker or in a measuring cup; it is stagnant and easy to follow the line of meniscus to see if it’s a ½ cup or 3/4. Then imagine measuring water in a river in order to build safer bridges; it tumbles over rocks, it changes speed, it experiences different water levels throughout a season.

Believe it or not, water movement is one of the most difficult phenomenon to solve. Yes, you can apply mathematics or numerical methods to solve complicated differential equations, but there are always some unknowns about turbulent flows (class 4 rapids) where general assumptions are made.

Rivers require intricate numerical models for river-type engineering problems, and I have been accepted to present on these intricate models at this years biennial National Hydraulic Engineering Conference (NHEC) in Columbus, Ohio. The Conference spans a week from 8/27 to 8/31, and I will be presenting on Friday, August 31st.

Per the NHEC website (, the conference is themed “Advancing Hydraulic Engineering through Innovation and Resilient Design,” and will address the challenges that transportation agencies face to construct, maintain, sustain, and improve hydraulic structures in the physical, natural, social, and economic environments of today and tomorrow. At this conference, I will be presenting on Two-Dimensional (2D) Hydraulic Modeling with Tidal Boundary Conditions.

Modelers typically use computer software packages where you input topography, flows, roughness parameters, and hydraulic structures. The software package uses the input to solve mathematical equations. It seems simple enough, but a modeler needs to have a conceptual understanding of numerical methods and know the limitations of the software package being used.

Whenever you hear the term “3D,” you think of an object in a space that has 3-dimensions, right? Similarly, water moves within a 3-dimensional space, where there is a z-component (up, down), y-component (left, right), and x-component (back, forth). What if I were to tell you that the movement of water in the z-direction (up, down) is not considered?

What would that mean? Well, what that means is that mathematically, we are simplifying a very complicated problem:  we are restricting movement of water to flow/move in 2D, 2-directions (x and y) and that is what 2D hydraulics is all about. Similarly, a one-dimensional (1D) hydraulic model is defined when the y-direction is neglected and water is confined to moving in the x-direction.

2D hydraulic modeling is not that new and has been available in an academia setting since the 80s. But in recent years, tools to develop 2D models have been readily available to engineers. A 2D model can’t be developed for every problem that we tackle, but it allows us to accurately represent actual real world conditions, make less assumptions and judgment calls, and communicate and show visualizations of flow movement to stake holders.


Written by Jeff Degraff

How has Hoyle, Tanner and the Aviation Industry Changed over the Last 45 Years?

jets with colored streams

In 1903 the first manned flight lasted 12 seconds and went for 120 feet. Today, unmanned aerial vehicles, more commonly known as drones, can stay airborne for up to 30 minutes and have a maximum range of 34 miles. August 19th is National Aviation Day, and it has us reflecting on how far the aviation industry has come since that first flight in 1903 and how our company has transformed along with it.


Forty-five years ago in 1973, Doug Hoyle and John Tanner formed Hoyle, Tanner. They began their firm providing only aviation and environmental engineering services. Today, Hoyle, Tanner has expanded into multiple engineering disciplines, with over 100 employees. One of our firm’s early major milestones in our aviation engineering service capabilities occurred in 1986 when Hoyle, Tanner was selected to prepare the Master Plan for Ellington Field in Houston, Texas. Ellington Field needed to maintain its role as a base for military and NASA operations, but at the same time become an airport for the public. Careful planning and diligent efforts were made to please those involved. In the end, the Master Plan was completed on schedule and rolled out to the public in 1987; the City had a new airport. Commercial, corporate, military and private interests were better served, and there was an expectation for an up-tick in regional economic activity. Hoyle, Tanner’s Airport Master Plan for this airport was ultimately used as a guide to implement a comprehensive program to plan and upgrade the former military base to meet its new civilian status.


Historically, aeronautics has evolved alongside technology. For approximately the first 20 years of the company’s history, our aviation design engineers and draftsman worked together to illustrate airfield improvement project designs on polyester drafting film known as Mylar. This was a labor-intensive process that could be compounded when considering alternative design scenarios. In the early 1990s, Hoyle, Tanner began using engineering design and drafting software. The incorporation of Autodesk Land Desktop allowed for increased accuracy, a more efficient design process, and the development of a product that can be more easily used to engage the public.


A major shift in the aviation industry occurred following the 2001 terror attacks. Prior to the attacks, you could follow your loved ones to the gate to see them off on their journey. Today all those good-byes happen before security check points. Two months after the attacks, on November 19th, Congress federalized airport security by passing the Aviation and Transportation Security Act. This security measure and others, such as body scans and shoe removal, were an effort to protect the safety of the traveling public. On a more practical note, cell phone and laptop charging stations have become the norm in every terminal to accommodate the lengthy wait time before, and between flights.


With the significant decline in pilots and the FAA expansion of regulations, the industry is seeing a drop in commercial airline pilots. The drop is not exclusive to pilots. A recent study by Boeing, projects the need for 790,000 new aviation pilots for the next 20 years. This equals to roughly 108 new pilots every day for the next 20 years. Aviation is not exclusive to pilots. Other careers include: engineering and mechanics, airport operations, and aircraft manufacturing. With several hundred thousand pilots and mechanics retiring over the next decade, the need for the new enthusiasts grows. For the past five years, Hoyle, Tanner has partnered each summer with Aviation Career Education (ACE) Camps to expose the next generation of aviation enthusiasts to the aviation field.


In the 45 years that Hoyle, Tanner has successfully navigated the civil engineering world, we are able to reflect on our roots in appreciation. So much of our success has stemmed from those early days mapping the skyways, and we owe much of our aeronautical achievements to that one milestone: The Master Plan for Ellington Field in Houston.

Drones: Enhancing Safety & Expanding the Aviation Community

Flying Drone

Small Unmanned Aerial Systems (sUAS), or as they are more commonly known as, drones, are changing inspection and construction methods and expanding the aviation community. Drones are the fastest growing segment of aviation. Currently, they are being used by public safety officials, realtors, farmers, engineers and of course by aviation hobbyists across the country. Depending on your perspective, drones are an emerging aerial solution or an impending aerial disaster just waiting to happen.

A major concern of the FAA regulators are the hazards of drones and manned aircraft in the same airspace. On December 12, 2017, Barrie Barber from Cox Newspapers published “FAA: Drones more deadly than birds.” In the article, Barber writes the “FAA has guidelines for building aircraft to withstand bird strikes of a certain weight, but tougher requirements do not exist specifically for drone collisions.” While it might seem obvious that a drone could do some damage, the impact damage of a bird and drone of similar weight are significantly different.

“The research found heavier, stiffer components, such as a drone motor, battery or a camera, could cause more structural damage to an aircraft than birds of the same weight and size,” said Kiran D’Souza, an Ohio State University assistant professor of mechanical and aerospace engineering.

While pilots have reported many drone sightings to the FAA, the FAA reports only one incident in the United States of a drone striking a Military Black Hawk helicopter in October 2017. In fact, the Unmanned Aircraft Safety Team (UAST) Drone Sightings Working Group released a new report on the Federal Aviation Administration’s (FAA) 3,714 drone sightings reports collected by flight crews, air traffic controllers and citizens from November 2015 to March 2017. The report found that only a small percentage of drone reports pose a safety risk, while the vast majority are simply sightings.

Despite growing pains employing drones, many industries and public agencies are adding them as tools and developing workflows to effectively employ them. Stamford Connecticut police Sgt. Andrew Gallagher did an interview for the Fairfield Citizen and explained how his police department has used drones to document and analyze accident scenes, conduct searches and track suspects. Fire Departments are now using drones with infrared cameras to quickly view fire scenes from different angles to best direct the crew response.

“I have stood on more fire trucks than most firemen looking for an overhead shot. We are always looking for something to stand on,” Gallagher says in the article. Drones provide different aerial shots that can give intelligence about where a person or accident could be – in real time, without putting lives in danger.

In addition to first responder use and Amazon’s idea to deliver packages via the airways, drones have provided opportunities in the professional planning and engineering field.

Evan McDougal, Airport Planning Manager with Hoyle, Tanner & Associates, Inc., is an FAA-certified manned aircraft pilot as well as an FAA Section 107 Remote Pilot. McDougal says that drones are an inexpensive data collection solution when airports have tree obstructions that have grown into the runway approach surfaces. These obstructions can limit the ability of pilots to use instrument approaches at night and in some cases the obstructions cause the FAA to increase the cloud ceiling or visibility requirements or limit how low a pilot can descend on approach to a runway. Many runway ends in Maine are not available at night due to known tree obstructions.

McDougal believes drones could be part of the solution.

Drones can quickly capture highly accurate aerial imagery that can be analyzed using photogrammetry software to identify the boundaries of tree canopy penetrating the imaginary (but very real) instrument or visual approach surface. An example of the typical results can be seen in this effort.

How it works: while following an autonomous flight plan the drone takes hundreds of georeferenced high definition photos. Photogrammetry software accurately stitches these photos together by matching thousands of key points within adjacent photos. This creates a full orthomosaic of the entire surveyed area and produces a very accurate three-dimensional model or point cloud that can be measured and examined thereby allowing engineers and airport owners to see exactly where runway obstructions exist.

This is but one use for a drone at airports. The technology is evolving very quickly and is limited only by our imagination.

Capturing Data in a New Era

This season Hoyle, Tanner employees are finding all sorts of ways to get out into the field. An essential aid to us in our field work is a GPS data collector. Employees from all departments have been utilizing the GPS data collector to collect centimeter grade accuracy GPS data in multiple states across New England. The variety of jobs the GPS is being used for includes tasks such as collecting utility pole locations in Massachusetts, flagging wetlands in New Hampshire, performing quality assurance checks of bridge superstructure construction in Vermont, utility asset management for multiple municipalities across New Hampshire and much, much more.

The strength of the GPS data collector is not only in its ability to collect highly accurate, horizontal and vertical data, but also in its extreme ease of use. Horizontal data can be collected in the World Geodetic System 1984 (standard latitude and longitude) or any of the state plane coordinate systems, and the vertical data is collected in the North American Vertical Datum of 1988. The GPS is powered by an android operating system, and requires no GIS or survey experience to learn how to use. The device also streams real time kinematic (RTK) corrected global navigation satellite system (GNSS) positions.  These real time corrections allow the user to see coordinates of shots as they are taken which also eliminates the need for special software to post-process the data back in the office.  The GPS data collector is capable of outputting both GIS shapefiles and ASCII text files, and it is also capable of inputting GIS shapefiles that can be viewed as a layer while collecting data in the field.

The GPS data collector is a powerful tool that has greatly improved the quality of field visits for the Hoyle, Tanner staff.  The ability to obtain highly-accurate GPS data with the click of a button while on project sites is changing the way we accomplish tasks, and we’re doing it in a more efficient manner.