transportation + infrastructure
How The U.S. Will Deploy Intelligent Transit Networks That Enable Connected Vehicles By Timothy Menard
Furthermore, it’s hard to determine whether the system is working because the equipment generally doesn’t produce event logs. When making such a large capital investment, it is very important to know whether the system is working so further expansion can be appropri- ately determined. However, these systems, when leveraged with state-of-the-art technol- ogies, are proving to be extremely effective. According to a recent sur- vey, the majority of city officials from communities leveraging transit prioritization technologies said they’re seeing growing improvements in on-time performance of their transit network. In today’s age of highly reliable large-scale communication access, there exists the opportunity to eliminate the hardware cost of transit signal priority solutions while maximizing the investment on current solutions. Many of today’s signal controller firmware vendors have software functionality to facilitate the function of placing virtual prior- ity calls. The information needed to place these virtual calls can be found at the transit agency. To better manage their fleet, agencies typi - cally have implemented tracking devices on each of their vehicles to report to their computer-aided dispatch and automatic vehicle location (CAD/AVL) software. With vehicle locations known in near real-time, software and networking can now be used to bridge the gap between transit vehicles and city signals to facilitate transit priority in a more reliable, sustainable and intelligent way. This removes the need for vehicle detection hardware at the intersection because vehicle location is known through the CAD/AVL system. This enables both priority calls from greater distances away from signals and priority calls coordinated among a group of signals. Furthermore, the system provides real-time insights on which buses are currently receiving priority along with daily reports of performance metrics. Prioritizing Traffic Flow & Optimizing Patterns The right method of placing priority calls to traffic signals is more sophisticated and is not constrained to fixed point locations. Unlike the current state-of-the-art of placing priority calls from the detection of buses at specific locations that starts a pre-programmed time of ar - rival, today’s solutions use a “vectorized” approach. In mathematics, a vector is an arrow representing a magnitude and a direction. In today’s advanced traffic management software, the arrow points in the direc - tion of the traffic light and the magnitude is the travel time. When the system is set up, traffic signals, bus routes, and bus stops all receive a digital representation on this vector. This produces a digital geospatial map where software can then track bus progression along bus routes. This results in a system that can dynamically place transit calls regardless of its location. Instead, the system makes precise pri- ority calls based on the expected time of arrival which is the basis for all TSP check-in calls supported by all signal controller vendors. And due to the nature of the tracking algorithm, any significant changes to ETA can be adjusted. For example, if a bus was predicted to skip a bus stop but didn't, the system will detect the change and adjust the priority call accordingly.
While America’s transportation infrastructure continues to be one of the country’s greatest historical accomplishments, as well as the lifeblood of the American economy, the system itself continues to have serious challenges during the last two decades. This is mainly due to the rise in traffic congestion which has ensnarled hundreds of cities across the country. Even in suburban areas, traffic congestion is a rising issue, especially when more delivery trucks are competing for road and curb space delivering our online shopping or- ders. What’s more, competing modes of transportation are also tying up traffic patterns. On average, American drivers lost approximately 26 hours in traffic during 2020, down from 99 hours in 20191. While this number shows an improvement year-over-year, this trend was largely due to the CO- VID-19 pandemic and the resulting millions of people reducing their transportation commuting by working from home. As more businesses invite employees back to the office, traffic problems are expected to rise again. All areas of the U.S. transportation system are focused on curbing this growing traffic trend by introducing and leveraging technologies and solutions that utilize data analytics to create a better traffic flow. Carmakers are also promoting more connected vehicle technologies to make cars and trucks on the roads smarter and more efficient by connecting to any number of databases and platforms that can help vehicles read traffic patterns in real-time. Advanced Transportation Systems Being Implemented Intelligent transportation systems (ITS) and connected vehicles are the future of reshaping this infrastructure. ITS systems are the applica- tion of sensing, analysis, and communications technologies to ground transportation to improve safety, mobility and efficiency. While this technology shows great promise, they are only as good as the platforms on which they run. To fully realize the promise of ITS and connected vehicles, transit agencies are now revisiting Transit Signal Priority (TSP) systems in the hopes of restoring route reliability and on-time performance. Over the last few decades, transit signal priority systems haven’t evolved much from being a transmitter on buses that send messages to receivers installed on traffic signals. The hardware cost to both signals and buses is quite high and requires annual maintenance to guarantee operation.
March 2022 csengineermag.com
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