Trial and Evaluation of Intelligent Road Studs
J-K Lam, L Vogel, FaberMaunsell, UK
This paper describes the Scottish Executive?s current trials of Intelligent Road Studs. These are capable of providing hazard warning, automatic incident detection, traffic monitoring, enhanced lane delineation and fog detection.
The Scottish Executive commissioned FaberMaunsell to advance their technical and operational understanding of Intelligent Road Studs (IRS) and evaluate the potential for trial implementation on the Scottish Trunk Road Network. This project comes under the umbrella of the EU co-funded project, STREETWISE.
Following experience with the COMPANION hazard warning system, where speed reductions of 10 to 20% and traffic flow smoothing were experienced, the Executive considered that IRS may provide effective hazard warning and traffic monitoring facilities, enhancing network monitoring capabilities and road safety as an alternative to both COMPANION and traditional methods. Such installations would not only provide an increased service to the network user, but also help toward the European Union target of 80% coverage for monitoring equipment on the Trans European Road Network (TERN).
The Executive is currently undertaking trials of an IRS system on the M8 approaching Glasgow with the same salient features as COMPANION so that a direct comparison can be made. This trial system uses standard UK motorway infrastructure and is capable of providing hazard warning, automatic incident detection, traffic monitoring, enhanced lane delineation and fog detection.
h4. IRS APPLICATIONS
IRS systems can currently offer the following functionalities:
* Hazard warning;
* Automatic incident detection;
* Vehicle detection (count/speed/classification);
* Enhanced lane delineation;
* Weather monitoring; and
* Ability to be controlled remotely and as a group.
Future functionalities currently in development include IRS mounted cameras and Automatic Number Plate Recognition (ANPR).
The ?self-healing? composite stud surface is cleaned by the polishing action of vehicles passing directly over the top, extending un-maintained lifespan. The internal IRS components can be removed from the housing in-situ, easing future maintenance and component replacement.
IRS may be powered by either integral solar-voltaic cells or a low voltage hardwire connection to a fixed supply. At this time, hardwired IRS provide more functionality and greater operational flexibility than the solar powered alternatives.
IRS can communicate with roadside equipment and each other using either fixed, hardwire connections or RF communications. Although it is possible to use wireless RF communications, the transmission range is limited to 30m and reliability is variable. Hardwire connections provide more robust, longer range communications, maximising functionality and operation.
h4. IRS TRIAL SITE APPLICATION
A 3 km site on the M8 Westbound approaching junction 6 (Newhouse) was selected. This site is part of the heavily trafficked motorway link between Edinburgh and Glasgow, but has comparatively poor detection and driver infrastructure. Congestion and incidents have a significant impact and, due to the altitude, the site also regularly experiences adverse weather conditions. Power and communications infrastructure exists through the chosen site.
h4. TRIAL IRS APPLICATION
Reviewing available options, it was decided that a hardwired system would best meet operational requirements. The IRS components required to achieve the desired objective include:
* Intelligent Road Studs at 18m intervals;
* Detector Studs at 500m intervals (nearside running lane only);
* Central Controllers/Processors;
* Verge Mounted Communications Infrastructure; and
* Verge Mounted Power Infrastructure.
A contract was awarded to Astucia (UK) Ltd. for the design, development and installation of a trial system at the identified site.
The system consists of twelve sets of 250m long IRS strings positioned along the outside edge of the hard shoulder. Seven cabinets housing controller, communications and power equipment were installed in the verge at 500m intervals through the site, adjacent to detector stud positions.
Traffic information, gathered by the detector studs, is relayed to the control/processor units. Data is then processed and measured against pre-determined thresholds, enabling
automatic identification of incidents or congestion. Algorithms determine the type and extent of alert required, before control units automatically relay instructions to the appropriate IRS strings. Activated IRS provide hazard warning to approaching traffic upstream of the incident via illumination, sequential or uniform flashing or colour/intensity change. The system also performs intelligent queue tracking so that only IRS upstream of any slow moving or stationary traffic are activated.
The site is now awaiting its final site acceptance test to then allow the evaluation period to commence.
There will be an evaluation period during which system performance, operational impact and driver reaction will be evaluated. The following criteria will be assessed under various traffic and climatic conditions, with and without IRS in operation:
* Vehicle Speed;
* Vehicle Flow;
* Lane Discipline; and
* Vehicle Headway.
In addition, the following studies will be undertaken:
* Accident figures and traffic data comparison for periods before and after IRS installation;
* Limited market research to obtain the views and observations of road users; and
* The performance of system components and functions evaluated to identify operational issues and benefits.
The results of this evaluation, and experiences gained through the trial, will be used by the Scottish Executive to determine how IRS could be best utilised on the Scottish Trunk Road Network in the future.
Association for European Transport