Roll way in the context of "Guide bar"

A rubber-tyred metro or rubber-tired metro is a form of rapid transit system that uses a mix of road and rail technology. The vehicles have wheels with rubber tires that run on a roll way inside guide bars for traction. Traditional, flanged steel wheels running on rail tracks provide guidance through switches and act as backup if tyres fail. Most rubber-tyred trains are purpose-built and designed for the system on which they operate. Guided buses are sometimes referred to as 'trams on tyres', and compared to rubber-tyred metros.

Guided buses are buses capable of being steered by external means, usually on a dedicated track or roll way that excludes other traffic, permitting the maintenance of schedules even during rush hours. Unlike railbuses, trolleybuses or rubber-tyred trams, for part of their routes guided buses are able to share road space with general traffic along conventional roads, or with conventional buses on standard bus lanes. Guidance systems can be physical, such as kerbs or guide bars, or remote, such as optical or radio guidance.

A guided bus line can be categorised as bus rapid transit and may be articulated bus and bi-articulated bus, allowing more passengers, but not as many as light rail or trams, which are not constrained to a regulated maximum size in order to freely navigate public roads.

A rubber-tyred tram (also known as tramway on tyres, French: tramway sur pneumatiques) is a development of the guided bus in which a vehicle is guided by a fixed rail in the road surface and draws current from overhead electric wires (either via pantograph or trolley poles).

Two incompatible systems using physical guide rails exist: the guided light transit (GLT) designed by Bombardier Transportation, and the translohr from Lohr Industrie (currently made by Alstom and FSI). There are no guide bars at the sides but there is a central guidance rail that differs in design between the systems. In the case of Translohr, this rail is grasped by a pair of metal guide wheels set at 45° to the road and at 90° to each other. In the GLT system, a single double-flanged wheel between the rubber tires follows the guidance rail. In both cases, the weight of the vehicle is borne by rubber tires to which the guide wheels are attached, which make contact with the road on concrete roll ways designed to minimise impact on the ground. Power is usually supplied by overhead lines, rechargeable batteries, or internal combustion engines where there are no overhead wires.