Why keeping count is so important for traffic management

Traffic engineers need to have multiple solutions in their toolbox to complete the most accurate and safe data collection programmes possible, explains Wes Guckert of The Traffic Group
Classification & Data Collection / November 21, 2023
(© ITS International | Adam Hill)
Detailed traffic data enables the identification of high-risk locations and informs the implementation of safety measures like traffic signals and pedestrian crossings (© ITS International | Adam Hill)

According to the transportation analytics firm Inrix, the average US motorist spent 51 hours sitting in traffic last year — 15 hours more than in 2021, though it remains 50% lower than the pre-pandemic high of 99 hours in 2019. Inrix also found that those taking to the highways in Chicago lost the most time to congestion last year at an average 155 hours, an hour less than commuters experienced in London, which has the distinction of having the worst traffic among major world cities studied. 

Looking at it from a dollars, or pounds, perspective, the Inrix Global Traffic Scorecard showed that congestion cost the UK economy £8 billion in 2021, which works out an average of £595 per driver. Meanwhile, the US lost $120 billion due to traffic congestion. 

Drivers are obviously paying a high price to sit in traffic – both in terms of their time and money. Traffic data collection plays a pivotal role in transportation and traffic management systems across the globe and is vital to the operation of any city. By accurately capturing and analysing traffic data, governments, urban planners, and traffic engineers can make informed decisions to optimise infrastructure, improve traffic flow and enhance overall transportation efficiency. 

Unfortunately, state and local governments often face limited budgets and dwindling staff. This can make it difficult for agencies to find the time and resources to evaluate available data collection technologies or thoroughly check on the data work being done by vendors or consultants.  Compounding this issue is the fact that many programmes are based on low-bid contracts, prompting vendors to limit their data equipment standards and testing to provide a lower fee.
All this, of course, can result in poor data collection. And poor data collected today can negatively impact development and expansion decisions, as well as maintenance needs and improvements, for the foreseeable future. 


What are the benefits of data collection?

Understanding the benefits of data collection will ensure agencies make these projects a priority. Specifically, key benefits of traffic counting data collection include:

1.    Infrastructure planning: By identifying traffic volumes and patterns, authorities can assess the need for new roads, bridges, and public transportation systems, ensuring optimal infrastructure development.

2.    Traffic flow optimisation: Traffic counting data aids in identifying congestion-prone areas and implementing measures such as signal timings, lane configurations, and alternative routes to improve traffic flow and reduce delays.

3.    Safety enhancements: Detailed traffic data enables the identification of high-risk locations and informs the implementation of safety measures like traffic signals, pedestrian crossings, and speed limit adjustments.

4.    Public transportation planning: Accurate traffic counting data assists in determining public transportation routes, schedules, and capacity requirements, contributing to efficient and sustainable transit systems.

Once government officials understand the full benefits of data collection, it is also worth understanding the various methodologies employed to collect traffic counting data, ranging from manual counts to advanced automated systems. Some common techniques include:

•    Manual counting: Trained personnel manually observe and record traffic data by using clickers, tally sheets, or video recordings. Although labour-intensive, this method is still employed in certain regions or for specialised studies.

•    Mechanical counters: Mechanical devices like pneumatic tubes or axle detectors are embedded on roadways to record vehicle movements, providing reliable data for traffic volume and classification.

•    Inductive loop detectors: These electromagnetic sensors installed beneath the road surface detect vehicles by measuring disturbances in the magnetic field, allowing for accurate traffic volume and speed measurements.

•    Video-based systems: Cameras strategically placed alongside roadways capture video footage that is later analysed using computer vision algorithms to extract traffic data, including vehicle counts, classifications, and speeds. Currently there is at least one methodology employing artificial intelligence (AI) protocols.


Is it difficult to collect axle-based traffic data?

Additionally, road tubes provide an accurate and affordable means to collect axle-based traffic data. The catch, however, is that they must be installed correctly, which can be tricky. First, all equipment used in conjunction with road tubes must be tested and checked to ensure that it is working properly. This means the air switches within the road counters must be working at similar sensitivities. The counters, in turn, must be free from debris or corrosion.


"Location is essential for improving the performance of the counter and assuring data accuracy"


Only new or lightly worn road tubes should be used. Tubes should be knotted, and pressure tested to ensure they do not leak air. This will guarantee a good pulse in the road tube which will be accurately received by the counter. Road tubes that leak or fail to provide equal air pulse will inevitably produce errors in axle data collection.

Location is essential for improving the performance of the counter and assuring data accuracy. Road tubes should be perpendicular to the road edge and struck straight-on by passing traffic. Ideally, traffic should be free-flowing, with minimal congestion or backing. Congestion or stop-and-go traffic will result in the appearance of low volumes. Areas where the roadway curves or congestion regularly occurs will generate errors in the data collected.

The counter itself must be able to decipher the pulses it receives correctly. This can be complicated because the counter has to decipher numerous issues which can impact the data collected. Tailgating, for example, may be misinterpreted as a truck or longer single vehicle, such as a limousine. Phantom pulses, which occur when air travelling down the road tube hits the far end of the tube and echoes back toward the counter, can confuse the counter into thinking it is seeing traffic where there is none.

What alternative tech can be employed for data collection?

There are, of course, alternate technologies that can be employed for data collection, but each comes at a price. The piezo method, for example, is the technology that most closely resembles the road tube method. Like the road tube, the piezo is embedded in the roadway perpendicular to traffic and registers the axles of vehicles as they cross. Far more accurate and much more sensitive than the road tube, the piezo will also last much longer in the roadway. Imbedding the sensors in the roadway, however, is costly, time-consuming, and labour-intensive. As a result, use of the piezo method tends to be reserved for long-term or permanent data collection programmes.

Advancements in technology have revolutionised traffic counting data collection, as well, which lead to more efficient and accurate systems. Some notable developments include Bluetooth and Wi-Fi tracking. Utilising Bluetooth or Wi-Fi signals emitted by vehicles, this technology anonymously tracks their movement and travel times, providing real-time data without the need for physical infrastructure.


"Drivers are obviously paying a high price to sit in traffic – both in terms of their time and money"


GPS-based tracking data from smartphones or vehicles allows for detailed tracking and analysis of travel patterns, speeds, and routes while mobile apps and crowdsourcing utilise data to enable users to contribute real-time traffic information, supplementing traditional data collection methods and providing additional insights.

The costs and risks to safety cited above necessitate the need for traffic engineers to have multiple solutions in their toolbox to complete the most accurate and safe data collection programme possible. With the rapid advance of AI solutions, the hope is that new, AI-enhanced video and radar technologies are now available on the market to help alleviate the gaps that currently exist in non-intrusive data collection efforts. This will enable governments to accurately—and safely—collect the traffic data needed to inform transportation planning and policy decisions in the future.

Through the implementation of advanced technologies, the collection and analysis of traffic data continues to evolve, offering greater opportunities to enhance traffic management strategies and optimise resource allocations, ultimately improving mobility both locally and globally.

Wes Guckert is president and CEO of The Traffic Group. He is also a fellow of ITE and on the National Small Business Leadership Council

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