“The next big thing is the one that makes the last big thing usable.”
— Blake Ross, Software Engineer
Q-Free MAXTIME Intersection Control (IC) software is integrated into TransModeler microscopic simulator, enabling a truthful digital twin of traffic intersection management and control through Q-Free traffic signal controllers.
Significant design efforts are dedicated to ensuring an intuitive workflow, prioritizing ease of use, a simulation environment that feels familiar and welcoming for traffic signal engineers.
TransModeler
TransModeler is an advanced microscopic traffic simulator, capable of capturing intricate traffic dynamics at the individual vehicle and driver level. Its precision spans to encompass lane-level geometric details, to the extent of generating SAE-J2735 compatible Map Object for V2X in Connected and Autonomous Vehicles applications. TransModeler has been successfully used in a wide range of national and international applications.
TransModeler makes a valuable resource for optimizing network-side traffic operations, designing transportation systems, and evaluating the impact of infrastructure changes, standalone or as part of a Decision Support System (DSS) of an ATMS/ICMS.
MAXTIME
MAXTIME IC is an intersection control firmware for ATC controllers, compliant with
a comprehensive range of industry standards including NTCIP, NEMA, and MUTCD. It is specifically engineered to operate on Linux-based NEMA-TS/ATC traffic signal controllers, widely used in North America for effective intersection control and management.
To enable MAXTIME intersection control with TransModeler, users need initially install MAXTIME Windows Suite, which provides a Windows PC version of the MAXTIME IC firmware.
MAXTIME Windows Suite acts as a virtual controller, emulating the functionalities of a traffic signal controller hardware. Instead of receiving detector calls from the field, it obtains those from the TransModeler simulator. On the other hand, the load-switch outputs from MAXTIME are interconnected with the simulated signal heads within TransModeler, not the signal heads in the field.
Workflow
In the integration of MAXTIME, TransModeler serves as the “digital twin” of the real world, providing a comprehensive transportation network model that includes signalized intersections, detectors, and other essential elements.
The simulation model meticulously incorporates intersections with georeferenced lane-level geometries, ensuring precise mapping of road networks essential for autonomous driving safety and flexibility. These intersections are managed externally by the MAXTIME software, with each intersection precisely controlled by a dedicated MAXTIME subprocess group.
One of the advantages of MAXTIME-integrated simulation is the remarkable speed which TransModeler operates simulations, a metric commonly known as “real-time factor.” For instance, a real-time factor of x60 indicates that the simulator can complete a one-hour simulation scenario in merely one minute of actual runtime.
The simulator operates on a clock that increments in steps of 0.1 seconds per step. At each simulation step, TransModeler sends the detector call state (ON or OFF) for every intersection to the respective MAXTIME subprocess group. In response, MAXTIME provides the load switch driver states of the subject intersection back to TransModeler. This information is then utilized by the latter to update the signals in simulation.
TransModeler incorporates a high-performance non-blocking thread model designed to efficiently manage MAXTIME subprocesses. This implementation ensures that out-process communication and interactions between TransModeler and MAXTIME subprocesses are both efficient and scalable, especially for large network-wide simulations with a large number of intersections or multi-replication simulations, where intricate MAXTIME subprocess group life-time management is critical.
MAXTIME spawns seven subprocesses for every intersection, requiring a sophisticated subprocess life-cycle management on the part of TransModeler to handle these intricacies effectively. It's worth noting that, as of now, there is a sense of pride in affirming that no other traffic simulator has surpassed TransModeler in this particular aspect! :-P
Load Switch and Detector Channel Configuration
From the standpoint of end users, whether they are traffic signal engineers or simulation modelers, the configuration process is not only intuitive but also straightforward. Refer to the video below - kindly overlook any shortcomings in video quality, as it is intended for a plain technical demonstration.
The load switch channels are not just numbers printed on an intersection diagram sheet - they are presented as live visual binding showing which turning movements are connected to. This innovative approach transforms the traditionally error-prone load switch mapping into a more user-friendly enjoyable experience, akin to observing a lively dance, adding a touch of fun to the process.
Simulation Runtime Controller Information
Accessing controller information during simulation runtime is made seamless through TransModeler "Controller Info" toolbar button. Users can intuitively modify the simulation speed, ranging from a slow 0.5 times real-time to real-time (1x), all the way to the fastest possible speed, as allowed by your computer hardware. Additionally, they can effortlessly observe the controller status in real-time by simply clicking on the intersection geometry, adding a layer of intuitiveness and straightforwardness to the process.
I cannot emphasize enough the efforts and OS-level programming techniques dedicated to achieving - not just the functional integration of MAXTIME with TransModeler, but also ensuring the integration is intuitive, seamless, and at the very least user-friendly, while at best, hopefully, attractive.
Use Cases
Simulation and Assessment of Advanced ITS Technology: Evaluate any advanced Intelligent Transportation System (ITS) technology interacting with Q-Free signal controllers, such as Transit Signal Priority or Adaptive Traffic Signal Control.
High-Performance City-Wide Simulation: Enable scenario-replay AI training with city-wide simulations, offering a platform for comprehensive training scenarios.
Integrated Corridor Management (ICM): Managing traffic flow across freeway, transit, arterial, and parking systems within a corridor, and optimizing the coordination of signals across interconnected intersections.
Predictive Analytics for Transportation Systems: Enhance decision-making with predictive analytics for transportation systems, allowing for proactive planning and optimization.
Seamless Controller Database and Firmware Bench Testing: Conduct thorough bench testing of controller databases and firmware, with the flexibility to simulate arbitrarily fast or slow clock time, comprehensive detector events, and edge cases of traffic flow scenarios that may be hard to capture in the field but involve life-and-death once occured.
Traffic Signal Optimization: Optimize traffic signal settings for improved efficiency, considering real-world scenarios and traffic patterns.
Educational Tool for ITS Engineers: Serve as an invaluable tool for educating the next generation of Traffic and Intelligent Transportation Systems (ITS) engineers, offering a hands-on experience in a virtual environment.
ATSPM Applications
The MAXTIME controller integrated with TransModeler can generate High-Resolution Signal Event data along with various simulation-based performance metrics.
The significance lies in the fact that this process produces signal events data at a pace much faster than real time, utilizing an authentic controller firmware, and in a controlled environment with different traffic flow scenarios and detection layouts.
This data can seamlessly integrate with any real-world ATSPM system, including the open-source ATSPM developed by the Utah Department of Transportation.
This line should bring a smile to your face, especially if you've ever grappled with the scarcity of high-quality traffic performance data. Most importantly, it enables you to cross-validate the ATSPM using other simulation-generated metrics as a basis for fine-tuning, adjusting, and diagnosing your field ITS infrastructure. Doesn't the prospect of an ATSPM-in-the-loop simulation sound enticing?