Between Cambridge, Huntingdon and St Ives in the English county of Cambridgeshire, runs a special bus service over a special route that consist of two narrow concrete rails instead of a regular asphalt road. The buses travel with each set of wheels over the parallel rails, just like a train. The margin for error is narrow, yet the buses attain speeds of 90 km per hour (55 miles/h). The best part is, the driver doesn’t even hold the steering wheel.

Guided buses combine the elements of both bus and rail systems to achieve a new mode of transport that is faster than regular buses because they don’t have to share congested public roads, and cheaper than rails. The buses are fitted with special guide-wheels that engage the short vertical kerbs on either side of the guideway. These guide wheels push the steering mechanism of the bus, keeping it centered on the track. On a normal road, the bus behaves like a regular bus and is steered in the normal way.

A guided bus on the O-Bahn Busway, Adelaide. Photo credit

Guided buses is mostly a British thing. There are only a couple of such examples outside the United Kingdom — one in Japan (Yutorīto Line, Nagoya), and another one in Australia (O-Bahn Busway, Adelaide), and an experimental busway in Essen, Germany.

The first guided busway in the United Kingdom was in Birmingham, branded as Tracline 65. It was an experimental 600 meter long track that was in operation between 1984 and 1987. Today, there at least seven major guided busways in the United Kingdom and several shorter ones and more are in the planning stages. In Mannheim, Germany, from 1992 to 2005 a guided busway shared the tram alignment for a few hundred meters, 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 It was discontinued as the majority of buses fitted with guide wheels were withdrawn for age reasons.

The Cambridgeshire Guided Busway, opened in August 2011, is the longest guided busway in the world at 25 km long. Before that, the 12 kilometer-long O-Bahn in Adelaide, which was opened in 1989, was the longest. The Cambridgeshire Guided Busway was such a success that 2.5 million trips were made in the first year itself – 750,000 more than forecasted. According to the Cambridgeshire County Council, 24 percent had switched to the busway after making the same journey by car.

The Cambridgeshire Guided Busway in St Ives. Photo credit

A Cambridgeshire Busway guided bus approaching Fen Drayton Lakes on its first day of running on August 7, 2011. Photo credit

A bus stops at the Science Park on the Cambridge Guided Busway. Photo credit

The concrete tracks of Cambridgeshire Busway two years before the bus service was launched. Photo credit

The guide wheel of a guided bus in London Guided Busway. Photo credit

The guide wheel of a guided bus in O-Bahn Busway, Adelaide. Photo credit

A Cambridgeshire Busway driver demonstrates hands-free driving. Photo credit

The O-Bahn Busway, Adelaide. Photo credit

The concrete rails of O-Bahn Busway, Adelaide. Photo credit

A guided bus on O-Bahn Busway approaches a bend. Photo credit

Close-up photo of the wheels of a guided bus on the busway. Photo credit

Not all guided buses are kerb-guided though. Siemens Transportation Systems developed an optical guidance system where a camera in the front of the vehicle scans 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) to steer the vehicle and keep it in its designated path. This system has been in place in Rouen, France, since 2001 and in Castellon, Spain, since June 2008.

In Eindhoven, Netherlands, there are two bus routes with magnets buried under the asphalt. Special buses fitted with magnetic sensors run over these routes and are automatically steered by an onboard computer using signals received from the sensors interacting with the magnets buried under the roadway.

The Douai region in France is also developing a public transport network using magnetic guidance.

An optically guided TEOR bus in Rouen. Photo credit

An optically guided TEOR bus in Rouen. Photo credit