We are currently experiencing a technological transformation of the transportation system on the scale of the transition from the horse-and-buggy to the automobile. The construction, automotive, computer, and telecommunications industries are joining forces, as well as vigorously competing, to create a transportation experience that only a short time ago was the realm of science fiction.
For example, the past few years have witnessed a rapidly growing market in connected-vehicle technologies. Connected-vehicle technologies enable a vehicle, cyclist, or pedestrian to communicate with other transportation users or the roadside infrastructure.
The earliest applications of these connected technologies focused on safety. For instance, today a connected vehicle is able to communicate with a smart intersection. If the connected-vehicle is not decelerating for a red light, the intersection can alert the vehicle. The vehicle may passively alert the driver through a warning message, alarm, vibration of the steering wheel, etc., and in some cases auto manufacturers have installed active systems that begin depressing the brake. Other safety applications abound, including rear-end collision alarms, pedestrian avoidance, and wet or slippery pavement warnings.
A great opportunity is presenting itself as these technologies come online. While initially stressing safety applications, it is clear that connected technologies have many potential operational, economic and environmental benefits. Innovative applications have been proposed that target improving fuel economy, reducing emissions, decreasing travel times, providing advance route guidance, and much more. Communities across the nation are deploying pilot tests and exploring how to leverage these technologies to improve our quality of life.
The city of Sandy Springs, in partnership with MARTA, the city of Dunwoody, and Georgia Tech researchers, is embarking on one such pilot test. This pilot test will seek to demonstrate the potential of connected technologies to improve bus on-time performance.
Currently, each bus has an onboard system that tracks the bus location. The goal of the city project is to leverage this data by providing it to the intersection signal controller. The signal controller has a built-in logic, known as “signal priority,” that implements small shifts in the signal timing to increase the likelihood of arrival on green, or early release from red, for a bus that is running behind schedule.
Similar priority systems have existed for decades; however, these systems were generally dependent on a line-of-sight technology. The buses would have an infrared flasher and the intersection an infrared sensor, allowing for the intersection to “see” when a bus was coming. However, roadway curvature, grades, and other line-of-sight obstructions limited the notification time window at the intersection of the impending bus arrival. In a connected-vehicle environment these constraints go away. With a longer heads-up, the intersection is capable of implementing more subtle and effective timing shifts to achieve the desired effect.
Such a system has the potential for significant impact. Buses are a highly efficient means of moving people. Effective utilization of transit increases roadway capacity, provides superior environmental performance in the movement of people, and where service is reliable, has the potential to reduce congestion for all roadway users.
However, the adjective “reliable” is not used lightly in the previous sentence. A complaint of many users, and the reason why many potential users elect other modes, is the lack of reliability found in many transit systems. People need to feel confident their transportation mode will allow them to arrive at work, go to the doctor’s office, and pick up their children on time. In addition to being late, the simple frustration of waiting for a late bus can push users away, causing them to reduce or eliminate their use of the service. The system proposed by the city has the potential to help improve the reliability of transit and make it a more attractive option for many people.
While the private auto is a critical component of our transportation system, alone it is unable to handle the demands of our society. Other efficient, reliable, transportation means are needed. As we continue to explore innovative new connected-vehicle applications, it is heartening that communities such as Sandy Springs are leading the way in applications beyond the single-occupant vehicle. I look forward to the many new and exciting innovations to come.