March 15, 2007 Nissan’s intelligent transportation system (ITS) project, which employs vehicle-to-infrastructure communication to enable synchronized communication between vehicles and traffic light signals, is about to begin the next test-phase. Nissan is installing the advanced traffic signal infrastructure within its Nissan Technical Center in Kanagawa to collect real-world vehicle data from several hundred employee cars participating in the project. The new advanced traffic system is designed to reduce accidents as well as ease traffic congestion, leading to improved on-the-road fuel consumption.
The test-phase conducted within Nissan’s premises is representative of real-world traffic conditions, where relevant data from vehicles can be collected and analyzed under a closely-monitored environment. The vehicle-data input and corresponding traffic-signal output from the intersections is computed by an advanced traffic light system specifically installed for the test program.
Two intersecting main roads, one running east-west for two kilometres and the other running north-south for one kilometre, each with multiple intersections and crosswalks, provide the basic parameters for the ITS experiment. Nissan has installed standard traffic lights and roadside optical beacons along these test-roads. Traffic data can be collected from the employee cars and shuttle buses without any on-board vehicle-modification. However, for specific data to support the development of the navigation program under testing, several hundreds employee cars will be equipped with the Vehicle Information and Communications System units.
1. Help reduce pedestrian accidents: Traffic signals place priority on crossing pedestrians
Based on the traffic-volume conditions, the system will calculate to optimize the timing lapse between crossing pedestrians and the change in traffic-signal. At times, pedestrians tend to ignore prohibitive red traffic signals at road-crossings when they do not observe any vehicles within sight, which is a common cause of accidents. The current test program will contribute to Nissan’s research findings on ways to avoid such accidents.
In principle, when traffic conditions are lighter in the daytime, the pedestrian signal remains on green while the driver signal is maintained on red. When a vehicle approaches and stops at the light, the vehicle-system communicates with the traffic light beacon, which then allows the signal to switch to green. This system emphasizes the safety of the pedestrians by ensuring the pedestrian has the right-of-way each time.
When a driver slows down accordingly on approaching an intersection, the system again synchronizes the timing of the green signal with the approaching vehicle to minimize the need for repeated stops and acceleration, thus improving on-the-road fuel consumption under city-driving conditions. The test program will also include a virtual school zone*2, which will appear as a warning alert to speeding vehicles on its on-board navigation display.
2) Help reduce collisions due to traffic-signal oversights: Have traffic-signal alerts on-board vehicles
The traffic-signal alert system automatically appears on the navigation display as a vehicle enters within a specified distance to an approaching traffic light. This alert system is already being tested on public roads under the ITS project in Kanagawa. The advanced test-phase at the Nissan Technical Center will further study the effectiveness of the alert system related to specific factors such as Human-Machine Interface (HMI). To help minimize accidents due to traffic-signal oversights, Nissan is testing the possibility of providing higher levels of alert, control, and even intervention when a driver fails to respond to the traffic-signal alert.
3) Reduce congestion caused by red traffic signals and right-turn queues
Traffic congestion is often caused by red traffic signals and vehicles queuing to take a right turn from one lane streets. Nissan is developing its ITS system to optimize the timing intervals between changing traffic signals to correspond with real-time traffic volume and flow in order to ease traffic congestion. The advanced system is able to detect and respond to right-turning vehicles, thus reducing the queuing time and improve traffic flow at intersections. Current research is moving forward on methods to synchronize groups of traffic signals to facilitate smooth traffic flow over a wider scope of traffic conditions.
This next phase of Nissan’s ITS research aims to optimize communication between vehicles and traffic signals to create an advanced traffic system where traffic signals operate in tandem with the vehicle-data input according to varying traffic conditions. Nissan hopes to help reduce traffic accidents and road congestion. Looking ahead, the company will continue working closely with the relevant government agencies in bringing the current experiment onto public roads under the existing ITS project in Kanagawa.
Under the Nissan Green Program 2010, announced in December 2006, Nissan is working to develop new technologies to reduce carbon-dioxide emissions from its vehicle line-up and global operating facilities. The ITS project in Kanagawa contributes to the NGP 2010 objectives by reducing traffic congestion and vehicle CO2 emissions through improved on-the-road fuel consumption.