is an issue, this system may not be practical: since the guide rail forms the return leg of the electrical circuit, accumulation of ice and snow on the rail could cause intermittent power interruptions to the vehicle. Also, as the vehicle does not place a significant portion of its weight on the guide wheel (most of it being supported by the rubber tyres), snow packed into the flangeways or atop the rail by road traffic could lift the guide wheel off the rail, leading the vehicle to go off course. Critics of the system also point out that, unlike a conventional tramway, GLT is a proprietary system, meaning that once having installed it, a city would face difficulties in purchasing vehicles from any manufacturer other than Bombardier. A standard tramway, by contrast, can easily accommodate vehicles from multiple suppliers; Nancy's neighbour Strasbourg, for example, has chosen the Alstom Citadis tram to supplement its existing Eurotram fleet. Because of the problems encountered by cities which have purchased the Bombardier Guided Bus (one of which has demanded compensation for the costs it has had to pay for the GLT) Bombardier will not sell any more GLT systems, at least until all the issues have been resolved. Legal status GLT vehicles are legally considered buses, and they must bear number plates, rear-view mirrors and lights. Unlike trams and Translohr vehicles, GLT vehicles have a steering wheel (though it is not used when following a guidance rail), and are capable of operating independent of the guideway. See also Bus rapid transit Roll way Translohr CRRC Autonomous Rail Rapid Transit Tyre Véhicule Automatique Léger (VAL) References External links Guided Light Transit official web site Railfaneurope.net Nancy photo gallery world.nycsubway Nancy and Caen photo gallery “Misguided Bus”? Nancy’s BRT Debacle Exposes Pitfalls of “Half-Price Tramway” - an article critical of GLT New Era Hi-tech Buses - containing much historical information, including pictures of the developmental prototypes at the test track in Belgium. Guided bus information and pictures Rubber-tyred tram Bombardier Inc. products