Personalized hazard warning system for safety improvement of vulnerable road users

The combination of selected Intelligent Transport Systems (ITS) technologies allows for individualisation of traffic information to improve traffic safety of vulnerable road users. This paper presents a short outline of recent international research results in this area, [1] [2]. The proposed method and prototypic technical solution described in the paper is based on the concept to keep the motorised traffic up-to-date with location based and individual information about accident risk spots and hazards in an urban or inter-urban street network. For traffic participants who are not familiar with a local urban traffic system it is more difficult to concentrate on additional warning signs. In particular if traffic signs are overlooked or accident hazard spots are not recognised by the driver, additional advice could be helpful. Examples of such dangerous spots are junctions with rail track crossings where trams have the right of way or pedestrian crossings where turns for cars are allowed on red as well as bicycle lanes at poorly visible road curvatures. The personalised risk warning system was implemented using the following components. Information regarding hazards and accident risk spots was provided from different sources such as collections of car accident report data involving injuries of pedestrians and cyclists. The acquired data collection was localised with geographical co-ordinates using suitable methods of either address based geo-coding or location based geo-referencing. A classification of hazard types is needed with respect to involvement of pedestrians, severity, frequency of occurrence as well as other categories in order to assign appropriate warning messages for hazard classes identified. For a delimited region like a city, relevant hazard warning messages are stored in a georeferenced database from which regularly updated messages can be broadcasted by Digital Audio Broadcasting (DAB) to be received by digital car radios. For the display and announcement of hazard warning messages, a standard PDA with positioning capability and wireless connection to the digital radio was used. The current vehicle position during driving is continuously compared to hazard message coordinates of the geo-referenced message table. For any matched locations of hazard spots, the according messages will be announced by speech and displayed to the driver. The technical solution described can also be adapted for usage in connection with commercial mobile navigation systems. In general it can be assumed that various ways to implement a personalised hazard warning system exist and are feasible by different means. First of all the combination of a traffic safety layer with commercial navigation software is obvious and requires specialised layers for at least the most favoured navigation systems on the market. Each of the adapted safety layers has to be provided over the same broadcast channel. The disadvantage of such diversification is that additional broadcast capacity is necessary for the provision of each thinkable adaptation. A remedy for this downside may be to provide the traffic safety layer over the internet for individual downloads. However the need for additional pre-trip preparations may raise the barrier to use the system at all. The alternative approach intends to establish a DAB service using the TPEG protocol to transmit voice data and warning messages that can be displayed and announced in a browser based application. The advantage of such a regional broadcasted data service for digital radio is that the software and necessary plug-ins can also be broadcasted and made consequently available for a number of different PDA platforms, whereas the more comprehensive data volume remains platform independent. For the covering abstract see ITRD E138091. This paper is available from http://ictct.org/dlObject.php?document_nr=538&/3_1Czogalla107_116.pdf