Description

The SKY (Start ITS from Kanagawa, Yokohama) Project was launched in October 2004 in Yokohama in order to contribute to the local community by reducing traffic accidents and traffic congestion. SKY is a private sector collaboration between Nissan Motor Co., Ltd., NTT DoCoMo, Inc., Panasonic Corp., and Clarion Ltd. The aim is to develop systems that can be realized and deployed. Support has also been provided from the public sector, namely the National Police Agency of Japan (NPA), the Kanagawa Prefectural Police and Universal Traffic Management Society of Japan (UTMS) regarding the intersection collision avoidance. The objective of the SKY Project is to reduce traffic accidents and ease traffic congestion through the use of ITS systems that communicate with the infrastructure, in addition to in-vehicle technology, and utilize information on nearby vehicles and the surrounding traffic environment, further resulting in time and fuel savings.

Objective

• Collaboration with infrastructure, in addition to technology in vehicles themselves to reduce traffic accidents.

• Use of information on the status of nearby vehicles and the surrounding traffic environment to ease traffic congestion.

Inputs

Onboard Units

All test vehicles have a standard Nissan Navigation system as well as Infrared Light Beacon Antenna (IR Beacon) widely available in Japan.

Infrastructural Units:

Intersection side video Cameras are used for driver behavior change monitoring.
The vehicles obtain outside information through Infrared Light Beacon Roadside Units (IR Beacon RSU).

Data Collection and Processing

Log system uses an up-link of vehicle real-time running data of 2000 participants to avoid stop sign/red signal violations and crossing collisions. A road side data logger stores the up-linked data. Log of the participant data who pass through the test sites are monitored.

The traffic flow and speed change data from vehicles without SKY functionality are also measured. Using the stored data the statistical analysis will show whether there is any difference between the data gathered from vehicles with or without safety support systems/information.

The traffic control centers are responsible for following tasks:

Collection, processing, recording and supply of traffic information and signal control.
Indication of traffic information on the traffic display board and the data display board.
Monitoring the system equipment.
Collections of regulatory information on traffic accidents and road works.
Processing information for external sources and responding to inquires.
Manual input to the system.

Results

Data Collected over 20,000 data logs during 2years period.

41% of vehicle exceeds the speed limit at 20m before the stop sign. The system can reduce that rate to 23% especially in high speed vehicles. Vehicles with the system show 35% increase in complete stop rate.
40 m before the intersection 38% of vehicle exceeds the speed at which drivers can avoid crash if a vehicle appear from side road. System can help reduce to 22% especially high speed vehicles.
The test results indicate that the availability of real-time traffic information data helps reduce the travel time by 8% and CO2 emissions by 4% comparing with car navigation system using batch processing and VICS compared to just map database only.

Limitations

Long term analysis shows that over-trust was seen when driver was seen when the driver, who experienced the system don’t receive information anymore at test sites.
The system works using infrared beacon which works on battery and requires constant replacement and repair that hinders the operations.
Infrared sensors are prone to disturbances due to sunlight and scattering effect which may reduce the efficiency of the data collected.
Latency or wrong data communicated due to limitation of processing capabilities might affect in the relevance of the message.
Lack of data for verification:- Real-time data and processing methods are not shown and vaguely mentioned.
Limited Participants:- There were only 2000 participants in order to test the system. Some participants never came to test sites.
Relevance of Up scaling: Since a lot of sensors are presently available in car to detect the speed and vehicle to vehicle communications available the infrastructural units might become irrelevant in future and therefore a loss of resource.