Path: EDN Asia >> News Centre >> Automotive >> Street traffic system model to help alleviate bottlenecks
Automotive Share print

Street traffic system model to help alleviate bottlenecks

06 Nov 2013

Share this page with your friends

Massachusetts Institute of Technology professor Berthold Horn used a damped-wave equation to create a framework for an instable traffic system. He also developed an algorithm, which can be considered a Lyapunov function, to address such a traffic situation.

The MIT professor presented the algorithm at the recent IEEE Conference on Intelligent Transport Systems. According to Horn, who is employed at MITs Department of Electrical Engineering and Computer Science, such instabilities arise from sudden brake manoeuvres in dense but otherwise flowing traffic. If one driver brakes, the following driver has to brake even stronger to avoid a collision, and thus the velocity variations build up upstream along a lane of traffic. This effect characterises a chaotic system where positive feedback generates velocity oscillations, according to Horn. Even Adaptive Cruise Control systems (ACC) cannot avoid the occurrence of such instabilities.

Horn's algorithm, in terms of maths, can be described as a Lyapunov function. Variables in this function are driver's reaction times, their desired speed, and their eagerness to reach that travelling speed, which in turn translates into the speed at which they accelerate as soon as they see gaps in front of them.

The algorithm could be implemented in ACC systems. However, to be effective, they will have to be modified. While today's ACCs only measure and control the distance to the vehicle ahead, a system based on Horn's algorithm would also have to take into account the distance to the following car. This means that the vehicles' sensor landscape would have to be extended by an additional backwards-looking radar or lidar sensor. Or, since Horn is expert in computer vision, by a camera-based, backward-looking system.

Horn's system, however, has a downside. It only functions if a high percentage of vehicles are equipped with it. AAC systems still are used predominately to premium class vehicles – radar and lidar sensors still are too expensive to deploy in more affordable vehicles. To overcome this chicken-and-egg problem, Horn suggests that the backward-looking sensor could be implemented as a video camera. Such cameras, Horn said, are readily available at affordable prices.

Want to more of this to be delivered to you for FREE?

Subscribe to EDN Asia alerts and receive the latest design ideas and product news in your inbox.

Got to make sure you're not a robot. Please enter the code displayed on the right.

Time to activate your subscription - it's easy!

We have sent an activate request to your registerd e-email. Simply click on the link to activate your subscription.

We're doing this to protect your privacy and ensure you successfully receive your e-mail alerts.

Add New Comment
Visitor (To avoid code verification, simply login or register with us. It is fast and free!)
*Verify code:
Tech Impact

Regional Roundup
Control this smart glass with the blink of an eye
K-Glass 2 detects users' eye movements to point the cursor to recognise computer icons or objects in the Internet, and uses winks for commands. The researchers call this interface the "i-Mouse."

GlobalFoundries extends grants to Singapore students
ARM, Tencent Games team up to improve mobile gaming

News | Products | Design Features | Regional Roundup | Tech Impact