JPL's Wireless Communication Reference Website

Chapter: Network Concepts and Standards
Section: Road Transportation Informatics

Traveller Route Guidance Systems

The development of present-day in-vehicle equipment started with
  1. Autonomous (electronic) positioning and navigation devices, to assist drivers in the process of way finding and providing information on the current location and how this relates to the destination, and
  2. communication systems for gathering and dissemination of information (e.g. RDS)

Route Guidance Systems

A combination of static navigation systems and dynamic traffic information was the next step, and resulted in the first types of dynamic navigation or guidance systems. Characteristic for this generation of information systems is the restriction of data transmission in only one direction (from traffic center to equipped vehicles) and (in most systems) only to all equipped vehicles together (broadcasting).

Under the EUREKA program, the CARin MINerve ATlas (CARMINAT) project (combining Philips' CARIN navigation system with the traffic information concept MINERVE and Renault's ATLAS project) is investigating the use of RDS-TMC to enable CARIN to react to changes in traffic conditions. The French version of CARMINAT is called INF-LUX. Trafficmaster is a hand-held or dashboard-mounted traffic information system for drivers on the M25 and interconnecting motorways around London, that issues congestion warnings detected by infra-red sensors mounted on motorway bridges and conveys this information in map display form.

PATHFINDER is an extension of the ETAK navigator with dynamic traffic information, with the addition of a speech synthesizer and a two-way radio for transceiving data. Without congestion information the PATHFINDER system continues to function as a standard ETAK navigator.

TravTek is an experiment in Orlando, Florida, to enable assessment and evaluation of the potential benefits and effects of implementation of providing car drivers with navigation and dynamic information, which involves the deployment of 100 vehicles equipped with in-vehicle display units.

In Japan, the development of in-car information and communication systems started in 1973, with the initiation of a national research and development program known as Comprehensive Automobile Traffic Control System (CACS), focusing on: route guidance (based on two-way digital communications via inductive loop transmissions), driving information, route display board and traffic incident information. As from 1979, when CACS was ceased, this led to the following two independent and competing programs. The Road/Automobile Communication System (RACS) was initiated in 1984 by the governmental Highway Industry Development Organisation (HIDO) to investigate the requirements of a system to provide two- way, real-time data exchange between vehicles and road-side units. This system was intended to use three micr wave type beacons: location beacons, traffic information beacons and individual communication beacons.

Also in 1984, the Advanced Mobile Traffic Information and Communication System (AMTICS) was conducted by the Ministry of Posts and Telecommunications (MPT). The concept AMTICS was, like RACS, to provide information from a central control center, to a navigation unit and display terminal on board the vehicles, by using cellular type terminals.

Dynamic Route Guidance

An obvious extension of the category systems followed quickly, and led to the development of dual-mode or dynamic route guidance systems, which enable interaction between traffic center in both directions and thus facilitate the vehicles equipped with dynamic route guidance devices to transmit information about their experienced traffic situation to a traffic center. Only few of these systems are currently in development. The ALI and the AUTO-SCOUT were combined into the conjoint ALI-SCOUT system, which has been tested in Berlin from 1988 using 250 infra-red beacon sites and 700 equipped vehicles in the field trial Leit und Information System Berlin (LISB) (jointly funded by Siemens, Bosch, the federal Government of Germany and the Senate of Berlin) and in London in the field trail AUTOGUIDE (by Plessey Controls). EURO-SCOUT (by SIEMENS) is the latest version of this ALI-SCOUT system. The French version of EURO-SCOUT is called ULIISE. SOCRATES (System Of Cellular RAdio for Traffic Efficiency and Safety), of which Phillips is the major partner (but not the prime contractor), was the largest project (V1007) in the DRIVE I program and uses cellular telephony (Global System for Mobile communications, GSM) for exchanging information between traffic center and vehicles. It is also planned that SOCRATES will supply CARIN and TravelPilot systems with dynamic traffic information. ADVANCE, is a project by the Illinois Universities Transportation Research Consortium, which constitutes one of the most ambitious demonstration and research initiatives into the effects and benefits of DRG systems and includes approximately 4,000 equipped vehicles in Chicago. In 1990, it was announced by the Ministry of Posts and Telecommunications (MPT) that RACS and AMTICS were to be combined in the Vehicle Information and Communication System (VICS) in order to work towards a joint development of vehicle information systems in Japan.

Probe Vehicles: Floating Car Data

If a sufficiently high percentage of vehicles is equipped with a dynamic route guidance (DRG) device, these can acting as roving traffic detectors.

Datacasting

In Europe, the Radio Data System (RDS) uses digital data signals which are inaudibly inserted into the FM-program on the same subcarrier frequency as ARI, but now pan-European, and the Radio Data System-Traffic Message Channel (RDS- TMC), that will use RDS capacity for transmitting digitally coded traffic messages to vehicles, requiring a dedicated TMC receiver to language-independently decode the messages.

Furthermore, in Britain CARFAX is being used, while in German speaking countries from around 1974 we find the Autofahrer Rundfunk Information (ARI), that alerts drivers for an upcoming traffic information broadcast, and ARI aufgrund Aktueller Messdaten (ARIAM), which uses automatic incident detection devices to reduce the elapsed time between observing and reporting traffic disturbances.

In the USA, Highway Advisory Radio (HAR) is operational, which is a special short-ranged radio that spatially localizes traffic information messages, using dedicated amplitude modulation (AM) transmitters located at the roadside, and Advanced Highway Advisory Radio (AHAR), which is a more advanced version of HAR, which provides an automatic interrupt when an advisory message is available.

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