Navigating Traffic Speed Studies

By: Tony Brijpaul, Co-Founder and Product Manager | Sep 14, 2023
Navigating Traffic Speed Studies - Miovision

In the fast-paced world of transportation and road safety, a few miles per hour can mean the difference between life and death.

As a result, understanding and accurately gauging vehicle speed is paramount for traffic management, law enforcement, and infrastructure development.

At Miovision, we’ve delved deep into the science of speed studies, testing various methods to uncover the most accurate and reliable approach.

Journey with us as we take you through the intricacies of speed measurement, shedding light on the challenges we’ve overcome and the innovative solutions we’ve developed.

What is Speed and How Do You Measure It?

Speed, in its simplest form, is the rate at which an object covers a distance over time – often expressed mathematically as V = d/t (where V represents speed, d is distance, and t is time).

But measuring speed can be anything but simple, and there are different ways to measure it depending on the level of accuracy required.

Average Speed vs. Instantaneous Speed

Average speed is sufficient for most applications.

To determine average speed, simply select two points in the real world, note the time it takes a vehicle to pass between them, and calculate the speed based on the distance and time elapsed.

This method provides a useful metric for traffic studies and road planning – however certain situations call for a more precise measurement known as instantaneous speed.

Instantaneous speed is calculated as time approaches zero, effectively capturing a vehicle’s velocity at a specific moment.

This is crucial for applications like traffic law enforcement and vehicle performance testing.

Miovision Catalyst Speed Lab: Uncovering the Truth About Speed Measurement

The Challenge

The biggest hurdle in speed studies is obtaining a “ground truth” – the most accurate possible speed reading of a vehicle.

Different measurement methods can yield varying results, and some methods are more accurate than others.

Our Approach

In pursuit of this elusive ground truth, we set up the Catalyst Speed Lab where we rigorously tested various speed measurement techniques to find the most trustworthy method.

Note: We occasionally asked volunteers to monitor their speedometers, but this method had limitations due to potential variations in speedometer accuracy.

So, fasten your seatbelts as we explore the intricacies of radar, road tubes, and the innovative solutions we’ve developed to overcome the challenges associated with speed measurement.

Our mission is clear: to make our roads safer and provide accurate speed data for better traffic management.

Here’s a rundown of the methods we tested:

Manually Operated Radar Gun

These devices are commonly used by law enforcement but may have limitations in accuracy for comprehensive traffic studies.

Automated radar units can provide accurate data in specific situations but may lack precision in determining measurement locations.

Road Tubes

Road tubes are placed on the road to detect vehicles passing over them.

They can reliably measure speed, but may encounter challenges when multiple vehicles pass over them at the same time.

Miovision Onboard Processing

Available on Scout Plus and Scout Explore (with Firmware version 6.1 and later), our portable video-based data solutions employ AI and onboard processing to provide continuous, precise speed data – a big asset for traffic studies.

Unveiling the Findings

In our quest to find the most accurate ground truth data so we can accurately determine how our new Onboard Speed Solution compares, we put these methods to the test in our Catalyst Speed Lab and compared all the results.

Speed Measurement Comparison

Speed Measurement Comparison - Miovision

Here we compare the speeds reported for individual vehicles across different measurement devices including road tubes, Miovision computer vision, and mounted radar.

Our findings revealed that while radar gun and road tubes often agreed, discrepancies did occur.

In contrast, computer Vision-based methods were generally closer to the ground truth while radar units were considerably less accurate.

Pitfalls in Radar-Based Measurement

The main challenge we encountered with radar-based speed measurement is its sensitivity to the angle at which it tracks vehicles, known as the cosine angle effect.

It’s important to note that the manually operated radar gun (positioned directly in line with the test vehicle to eliminate the cosine effect) consistently delivered accurate results.

However, the automated radar box, affixed to a roadside pole, demonstrated subpar performance when measuring incoming traffic (and notably poor performance when tracking outgoing traffic).

Pitfalls In Radar-based Measurement -Miovision

Automated radar units excel in monitoring speeds within a lane or two, but struggle when pinpointing the precise measurement location along the road.

This can lead to inaccuracies in speed measurements.

Another challenge that arises when an automated radar unit is angled up the road is knowing exactly the specific spot the vehicle’s speed is being measured.

Given that most Vehicle Speed solutions rely on average speed rather than instantaneous speed, the exact measurement location becomes a critical variable that can greatly affect the accuracy of the data collected.

Road Tubes: A Mixed Bag

Road tubes offer a seemingly straightforward way to gauge vehicle speed: they register the moment a vehicle passes over them.

However, their installation and usage come with challenges.

Affixing rubber tubes to the road requires hammering down multiple nails, a process that can be daunting, especially in busy traffic areas. Installing and retrieving road tubes require technicians to step into harm’s way for extended periods of time, often during especially hazardous conditions.

Moreover, road tubes may misclassify vehicles when multiple cars cross simultaneously, resulting in measurement errors. (When 2 cars drove over the road tubes at the same time in different directions, they were sometimes classified as a bus traveling at 130 KM/h.)

In our tests comparing video tracking to road tubes, our system’s classifications were generally more accurate.

Even in cases of occlusions (when two vehicles pass each other), video tracking had fewer errors compared to road tubes.

Computer Vision: The cutting-Edge AI Solution for Accurate Speed Measurement

Harnessing the power of Miovision’s well-established Computer Vision algorithm, plus an additional measurement of real world space to allow for extra scene calibration, we are able to reliably calculate vehicle speed across a wide variety of scenarios while also leading the industry in precise vehicle classification.

In Conclusion

Our exploration of various speed measurement methods revealed both the strengths and weaknesses of industry-standard approaches.

While radar and road tubes can provide useful data under specific conditions, they are far from flawless.

Driven by our dedication to precision and innovation, Miovision has engineered a groundbreaking internal tool specifically to overcome the limitations found with the standard speed measurement methods for roads and highways.  

Drawing on insights from our Catalyst Speed Lab, we’ve developed a highly reliable solution for accurately measuring vehicle speed.

This has served as the framework for our new onboard speed solution, tailored for comprehensive traffic studies.

Our Speed feature is an industry-standard report with an accuracy rate of +/- 10% at the 85th percentile speed, and can be further categorized by vehicle classification for up to 4 lanes of traffic even at high volume and speed Highway situations.

Cutting-edge Ai Solution For Accurate Speed Measurement - Miovision

Miovision Catalyst Speed Lab

While traditional methods like radar and road tubes have their merits, they are not infallible. 

In the ever-evolving world of transportation and road safety, accurate speed data is indispensable.

At Miovision, we continue to push the boundaries of speed measurement technology, ensuring that our roads become safer for everyone.

Speed studies are now available for our customers on Miovision Scout Plus and Scout Explore.

To upgrade your device, visit the latest Release Notes located on our website.

For more information about how to deploy and configure Scout Explore and Scout Plus to accurately capture vehicle speed data, please refer to our help page.

Miovision’s Commitment to Vision Zero

Catalyst Speed Lab has not only unraveled the complexities of speed studies, but it has also reaffirmed our unwavering commitment to safety.

Through our core areas of expertise—Speed Studies, Safety Studies, and Preemption Solutions—we are driving towards a safer future on the roads, where accurate data, comprehensive studies, and preemptive measures combine to protect lives and enhance traffic safety.