This piece was originally published in the May/June 2019 issue of electroindustry.
Bryan Mulligan, CEO, Applied Information Inc. Bryan Mulligan is the Chair for the NEMA 3TS Transportation Section. Connect with him on all things transportation at appinfoinc. com and listen to his talk show “TravelSafely with Bryan Mulligan” on Business Radio X.
One of the most pressing debates in the smart mobility sphere is the question of how to implement connected andautonomous vehicle (CAV) technology: should manufacturers use dedicated short-range communication radios (DSRC) or cellular- based vehicle-to-everything (C-V2X)?
CAV technologies have the potential to improve roadway safety. They are being used to improve communications between vehicles, infrastructures, cyclists, and pedestrians. Although these technologies are a recent addition to the marketplace, they have several key real-world applications, which include emergency vehicle pre-emption, collision warnings, red-light-running alerts and many others. In order to address the DSRC vs. cellular debate, Applied Information, Inc. (AI), and the University of Alabama (UAB) deployed and tested both technologies in the streets of Tuscaloosa, Ala.
Figure 1: Traffic Cabinet Setup
The main advantage of DSRC radios is that they provide point-to-point communications, allowing for near-instant communication between units. Recently, however, cellular-based technologies have gained favor in the transportation industry as an alternate communication platform. Proponents argue that, at the speed cellular technology transmits data, any potential latency doesn’t affect the practical implementation of CAV applications. With the coming of high-speed 5G, cellular communication will reach the speeds necessary to handle point-to-point communication between vehicles and infrastructure.
In 2017, in order to evaluate the ongoing debate, AI and UAB partnered to deploy connected vehicle (CV) technology in 85 intersections throughout Tuscaloosa, creating a living lab. The team deployed both DSRC radios and cellular-connected devices to create a “hybrid connected vehicle system.” Additionally, the team rolled out an app that provided residents with C-V2X communications.
AI and UAB have found several key results so far. Traditionally, the main justification for choosing DSRC technology over cellular is that DSRC communications have a much lower latency period. However, this project showed 4G LTE communications had a latency period of less than 300 milliseconds.
Figure 2: Connected Vehicle Smartphone App
The study also found that, in practical terms, C-V2X technology was easier to distribute to residents. Units that communicate with DSRC radios cost around $1,000 on average and usually require modification of one’s vehicle. This makes widespread distribution of DSRC technology expensive and impractical for most people. However, a majority of Americans have a smartphone capable of using cellular technology today, and most automotive companies have promised to include 5G C-V2X communications in their upcoming cars. This means that C-V2X communications will come at no cost to the end user. Even if a vehicle weren’t directly programmed with CV technology, drivers could easily download an app to access C-V2X communications.