Guided buses may be articulated, allowing more passengers, but not as many as light rail or trams that do not also freely navigate public roads.
Only a few examples currently exist, but more are proposed in various countries.
The first guided busway in the United Kingdom was in Birmingham, branded as Tracline 65, 1,968 feet (600 m) long, experimentally in 1984. It has since been removed. A number of guided busways have since been planned or built in the United Kingdom. In Mannheim, Germany, from May 1992 to September 2005 a guided busway shared the tram alignment for a few hundred metres, which allowed buses to avoid a congested stretch of road where there was no space for an extra traffic lane. It was discontinued as the majority of buses fitted with guide wheels were withdrawn for age reasons. There are no plans to convert newer buses.
The KGB guidance mechanism is a development of the early flangeways, predating railways. The Gloucester and Cheltenham Tramroad of 1809 therefore has a claim to be the earliest guided busway. Earlier flangeways existed, but were not for passenger carrying.
Rubber-tired "trams" (trolleybuses)
A development of the guided bus is the "tramway on tires", 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. Power is usually supplied by overhead lines or by rechargeable batteries where there are no overhead wires.
The Translohr system operates as a guided vehicle at all times, while with the Bombardier system the vehicles can be driven autonomously as requirements dictate, such as journeys to the depot. Consequently, the Bombardier vehicles are legally considered buses, and must bear rear-view mirrors, lights and number plates, and are controlled with steering wheels and pedals like ordinary buses, though the steering wheel is not used when following the guidance rail. On the other hand, Translohr vehicles operate like standard trams and cannot move without guidance, so it is not classified as a bus and are not equipped with number plates.
These systems are intended to offer a more tram or light rail-like experience than a regular guided bus, and offer some advantages over steel-wheeled trams, such as a potentially smaller turning radius, the ability to climb steeper gradients (up to 13%), and quieter running around corners. The infrastructure installation can be less complicated than the installation of a complete tram line in an existing street. These systems have been likened to the tram equivalent of rubber-tired metros, and they are also less efficient than steel-wheeled light rail vehicles. There is no evidence to prove the superiority of either guidance system. Both Bombardier and Translohr have had derailments during operation.
Optical guidance relies on the principles of image processing. A camera in the front of the vehicle scans the bands of paint on the ground representing the reference path. The signals obtained by the camera are sent to an onboard computer, which combines them with dynamic parameters of the vehicle (speed, yaw rate, wheel angle). The calculator transmits commands to the guidance motor located on the steering column of the vehicle to control its path in line with that of the reference.
Optical guidance is a means of approaching light rail performance with a fast and economical set-up. It enables buses to have precision-docking capabilities as efficient as those of light rail and reduces dwell times, making it possible to drive the vehicle to a precise point on a platform according to an accurate and reliable trajectory. The distance between the door steps and the platform is optimized not to exceed 5 centimetres (2 in). Level boarding is then possible, and there is no need to use a mobile ramp for people with mobility impairments.
The OPTIGUIDE system, an optical guidance device developed by Siemens Transportation Systems SAS, has been in revenue service since 2001 in Rouen and Nîmes (only at stations), France, and has been fitted to trolleybuses in Castellon (Spain) since June 2008.
Other experimental systems have non-mechanical guidance, such as sensors or magnets buried in the roadway. In 2004, Stagecoach Group signed a deal with Siemens AG to develop an optical guidance system for use in the UK.
Two bus lines in Eindhoven, Netherlands are used by Phileas vehicles, a combination of tram and bus. Line 401 from Eindhoven station to Eindhoven Airport is 9 km (5.6 mi) long, consists largely of concrete bus lanes and has about 30 Phileas stop platforms. Line 402 from Eindhoven station to Veldhoven branches off from line 401 and adds another 6 km (3.7 mi) of bus lanes and about 13 stops. The regional authority for urban transport in the Eindhoven region (SRE) has decided not to use the magnetic guidance system any more for some years.
The Douai region in France is developing a public transport network with dedicated infrastructure. The total length of the lines will be 34 km (21 mi). The first stage is a line of 12 km (7.5 mi) from Douai via Guesnain to Lewarde, passing close to Waziers, Sin-le-Noble, Dechy and Lambres-lez-Douai. 39 stop platforms will be provided with an average distance between the stops of 400 m (440 yd). A number of stops will be placed at the right side of each lane. Central stops between both lanes will be placed at locations with limited space at the right side. This requires vehicle to have doors on both sides.
On November 3, 2005, a licence and technology transfer agreement was signed between Advanced Public Transport Systems (APTS) and the Korea Railroad Research Institute (KRRI). KRRI develops the Korean version of Phileas vehicle by May 2011.
Since June 2013, 3 miles (1.5 miles each way) of the Emerald Express (EmX) BRT in Eugene, Oregon has used magnetic guidance in revenue service on an especially curvy section of the route that also entails small radius S-curves required for docking. The driver controls braking and acceleration.
On kerb-guided buses (often abbreviated to KGB) small guide wheels attached to the bus engage vertical kerbs on either side of the guideway. These guide wheels push the steering mechanism of the bus, keeping it centralised on the track. Away from the guideway, the bus is steered in the normal way. The start of the guideway is funnelled from a wide track to guideway width. This system permits high-speed operation on a narrow guideway and precise positioning at boarding platforms, facilitating access for the elderly and disabled.
Examples of guided busways
- Cambridgeshire Guided Busway, England – Huntingdon to Trumpington - 2011
- Crawley Fastway - 2005
- Essen, Germany - 1980
- O-Bahn Busway, Adelaide, Australia - 1986
- Yutorīto Line, Nagoya, Japan. - 2001 - In Japan, the bus is legally considered as a sort of railway.
Tram-like guided busways include:
- Bombardier Guided Light Transit – Caen, France; Nancy, France
- Translohr – Clermont-Ferrand tramway, France; Tianjin, China; Shanghai, China; Padua, Italy; Istanbul, Turkey
- Phileas – Eindhoven, Netherlands; Douai, France
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|Wikimedia Commons has media related to Guided bus.|
- Guided bus information and pictures
- Adelaide O-Bahn
- First Group guided busways
- Translohr official site
- Guided Light Transit official web site
- Cambridgeshire County Council's Guided Busway project
- "An Update on Curb Guided Bus Technology and Deployment Trends", Journal of Public transport 2006 BRT Special Edition (PDF 964Kb)
- University of Minnesota's ITS Institute "BRT Technologies: Assisting Drivers Operating Buses on Road Shoulders"