State-of-the-art Traffic Signals, Circa 1937

Although the primary focus of this blog is Next-Generation ITS, I came across this interesting educational film produced by Chevrolet in 1937, that shows the “state-of-the art” of that era.  Some of the traffic management applications are fascinating, and others just plain scary.

Traffic Signal System Operations via Smartphone Technologies

Mobile technologies are supporting the development of new traffic management applications that are drastically changing traditional traffic management system architectures. What once seemed several years out is now showing early signs of first-generation deployments, with beta applications and system field trials already underway. 2011 has seen the emergence of several traffic management applications focused on the use of personal computing devices for sourcing traffic data and feeding new traffic management central software applications. In addition, new applications have also emerged this year that plan and manage traffic flows without directly interfacing with existing signal timing software.

An early entrant is being developed by researchers at Princeton and MIT, which bases signal operations and route planning on visual data collected and processed by vehicle-based smartphones. SignalGuru utilizes dash-mounted smartphones and video analytics to detect and process signal traffic signal indications via Green Light Optimal Speed Advisory (GLOSA) . The new application is considered “passive” in that it does not directly interface or manage signal timing and signal system operations.

Siemens has commenced with testing of a new smartphone-based pilot project installed for 400 signalized intersections in Harris County (Houston), Texas. The system utilizes Bluetooth readers and a new central application to measure traffic flow and traffic densities, then utilizes a central application to modify signal timing parameters. This form of traffic management via smartphone technologies is considered “active” as the application actually interfaces with, modifies and manages the central traffic management software.

References and Resources
Siemens (Active)
http://www.siemens.com/innovation/apps/pof_microsite/_pof-spring-2011/_html_en/traffic-systems.html
SignalGuru (Passive)
http://www.princeton.edu/~ekoukoum/SignalGuru.html

LED Traffic Signals and Vehicle Lights for Optical Broadband Communications [Research]

Visible Light Communication (VLC) is a rapidly emerging field that focuses on the use of light sources (between 400 THz and 800 THz) for the primary purpose of broadband communications. In order to transmit data over light, the light source (transceiver) is pulsed on and off rapidly to create a data stream, similar to fiber optic communications, but in the wireless form, or “Free-Space Optical Transmission“. By pulsing lights many thousands (and millions) of times per second, data transmission occurs at a rate undetectable by the human eye.  Optical receivers convert the light pulses to an electronic signal on the receiver end. The Light Emitting Diode (LED) is the primary form factor currently undergoing extensive research.

The recent wholesale transition from incandescent traffic signal lights to LED lights was originally based on the fact that LED signals utilize as little as 15 percent of the power required for incandescent lamps, and the lamps are brighter and have a greater life-span.  As a secondary benefit, greatly reduced power requirements have enabled wide-scale implementation of uninterruptable power supplies (UPS) for power backup at critical signalized intersections.  In recent years, research associated with visible light communications has focused on the use of existing LED traffic signals as a potential source for implementing optical broadband communications.  Researchers are currently examining the viability of utilizing LED traffic signals for communications between intersections and between the intersections controller and approaching vehicles.

Another potential use of VLC within the transportation community would utilize VLC for  vehicle-to-vehicle (V2V)  (or headlight to taillight) communications.  LED vehicle lights are also technically capable of providing communications.  The primary futures uses for this type of communications would be ideal for collision-avoidance systems.

From Ledgb.com
http://en.ledgb.com/detail-4081.html

Further Reading
LED Traffic Light as a Communications Device
http://www.eee.hku.hk/~gpang/IARL/Publication/LED%20Traffic.pdf
Enabling Vehicular Visible Light Communication (V2LC) Networks
http://networks.rice.edu/papers/vanet-liu.pdf

The Evolution of Traffic Signal System Software – What’s next?

It’s no secret that traffic signal systems are an essential component to the day-to-day operations of any urban transportation network.  At the core of these systems is the central software, which typically provides centralized command and control functions, including management of communications between signalized intersections, as well as management of signal phasing, signal timing and signal coordination plans.  These applications also often include command and control capabilities to operate and manage ITS technologies such as closed circuit television (CCTV) cameras, dynamic message signs (DMS), and vehicle detection systems. Due to the operational importance and magnitude of their direct interface with the traveling puiblic, central applications hold the greatest potential for improvement of operational efficiencies and optimization of existing transportation networks.

Applications currently available provide a wide range of features and options for traffic management agencies.  Most of the current vendors have been in the business for 20 years or more, so their products are well seasoned.  Current centralized applications do a nice job of providing basic command and control of typical traffic signal systems, provided the operating agencies are dedicated to maintaining the fiscal and physical resources required to operate and maintain these systems.  However, during tough economic periods such as these, operating agencies have become increasingly short-staffed and must provide existing operational levels with extremely constrained budgets. In many instances, monitoring and management of central software is given up for responding to operations and maintenance issues in the field, thus increasing the need to further streamline and automate these applications.

One of the shortcomings of central signal system software is their ability to rapidly evolve.  Unfortunately traffic signal system software has historically evolved at a glacial pace, sometimes requiring 10-15 years for significant feature upgrades.   When newer transportation technologies emerge, it is essential that the central applications adapt in order to integrate the new technologies.    

New technologies such as connected vehicles, smart phones and cloud computing will require significant modification to existing software platforms.  With the pending onslaught of “connected devices” on its way, it will be necessary for the traffic signal applications to communicate with other transportation and infrastructure platforms.  New operations models, including the Vehicle-to-Infrastructure (V2I) model, will exchange data and information between vehicles and traffic management systems, most notably Signal Phase and Timing (SPaT) data. Will “open data” and open-source platforms such as Linux or Android ever be able to make it into the central applications?   Only time will tell.  

The recent emergence of cloud-based architectures also holds potential value for traffic signal systems.  Cloud-based central apps would provide an optimized tool for regional signal system operations, establish a centralized data warehouse open for third party development and lesson the infrastructure and staffing needs associated with operating and maintaining today’s central applications.