Local Researchers May Hold the Key to Making Intersections Safer

Not long ago, the Texas Department of Transportation released their latest list of the most dangerous intersections in the state of Texas. Sadly, among the Texas cities with the most dangerous intersection, San Antonio was number two, behind Houston.

That may have been the impetus behind a recently disclosed project from the University of Texas at San Antonio (UTSA), for a “smart stop sign” that they are hoping will be an inexpensive way to reduce the number of auto accidents at intersections.

The new design seems relatively simple, in that it adds a flashing light sensor over an existing stop sign. The light is triggered by a passive infrared sensor that picks up an approaching vehicle’s thermal signature, classifies it and flashes the light to alert a driver that they are approaching a stop sign. The hope is that the added visibility will reduce the number of failure-to-stop accidents, especially in rural areas, where all sorts of signs can be very difficult to see.

What Is a “Smart Stop Sign”?

According to UTSA’s Department of Electrical and Computer Engineering, these solar-powered devices will mount on top of existing signposts and they will cost well under $100, which is a significant saving over conventional vehicle detection systems. They will also cost far less to install. According to researchers, the system is able to determine the vehicle’s direction of travel, estimates the velocity of its thermal signature and determines the classification of the vehicle. Because the flashing light should give road users a better chance of seeing the sign and coming to a stop safely, it should prevent a lot of accidents.

This could be a big deal. The lead researcher on this project also headed another research project, called the Motorcycle Crash Causation Study (MCCS). That study found that about two-thirds of all crashes of all types occurred at intersections. Another study, from Virginia Tech, also made a compelling case for improving the status of signs and signals at intersections. According to the Virginia Tech study, an uncontrolled intersection presents nearly 41 times the risk of no intersection. Since a parking lot or driveway intersection represents at least eight times the risk, that makes uncontrolled intersections incredibly dangerous.  And if signs cannot easily be seen, they may as well be uncontrolled.

A lot of technology is already available to make intersections safer. For example, there is vehicle detection technology available, but implementing such technology could be extremely difficult and prohibitively expensive.

Why is This Great for Rural Roads?

And make no mistake; according to UTSA’s research, rural roads are where the biggest problem in Texas. While rural roads in Texas move less than 20 percent of all traffic, they account for more than half of all road deaths in the state.

When UTSA tested the “smart stop sign,” in practical use, it had a vehicle detection accuracy rate of 90 percent,  which means 90 percent of the time, it detected a vehicle approaching the stop sign.  At the same time, the vehicle classification accuracy rate was just over 70 percent, which means it was pretty accurate at detecting which type of vehicle was approaching. While that may not be as accurate as other vehicle detection systems, its accuracy is quite a bit higher than more traditional detection systems, such as microwave radar systems, magnetic loop inductors, and video image processors. Best of all, the cost of their “smart stop sign” system promises to be a fraction of the cost of those traditional systems.

The savings come with the use of a multi-pixel passive infrared sensor, which is a type of sensor that observes precise measurements of temperature for different locations within the sensor’s field of view. That includes motorcycles. This type of sensor observes changes in temperature to detect the vehicles.

“Smart Stop Signs” Bring No Privacy Concerns

One other advantage to the UTSA “smart stop sign” system is that it poses less of a privacy risk than, say, traffic cameras. This is because the thermal sensor doesn’t capture images, which means the drivers approaching the stop signs stay completely anonymous.

At first, UTSA researchers didn’t consider the indirect benefits to the most vulnerable road users, like bicyclists and pedestrians, but changed their focus once they saw how the system improved safety at the intersections they tested. Recently, they added a project in which the research team specifically looks at how the system can be improved to specifically benefit those road users.

There are also plans to test these “smart stop signs” on public roads. UTSA researchers are currently working with municipalities throughout Texas who are interested in testing the system. In addition, they are working with vendors who are interested in implementing the technology.

It is great to see that local researchers are at the forefront of creating new innovative technologies that can improve road safety for everyone in San Antonio, throughout Texas and elsewhere.

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