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Any public transport system will run faster and more smoothly if it can be segregated from other traffic. Bus Lanes and Priority Access Points (Bus Gates) are intended to improve bus services by this means.

Degrees of Segregation Within the Carriageway

• Trams can be segregated from road traffic in the same way as are bus lanes, by means of road markings, but these lanes are open to similar abuse by motorists.
• The surroundings of tram tracks can be paved with a special roughened surface or cobbles or sets, which will discourage other traffic. This cannot be shared with buses because of the rough ride it would give.
• The tram tracks can be laid on sleepers with no road surface. Cars cannot be driven along the track, but this does not seem to have prevented some drivers in Croydon from attempting this and becoming stranded. Pedestrians could cross the track but should be discouraged from doing so because of the risk of tripping or being stranded on the tram track by heavy road traffic.
• A raised concrete curb or a change of level can prevent car access, but could lead to accidents and prevents pedestrians from crossing the road.

Segregation From the Carriageway

• A fence can be erected to segregate a tramway running alongside a roadway. This can only be done where thre are no road, cycle or pedestrian alignments crossing the carriageway.
• A completely separate tram track can be laid for total segregation. High speeds are possible with this arrangement but access by passengers is made more difficult.

Disadvantages of Segregation The degree of segregation of a tramway is a matter of balance. Whilst high degrees of segregation from other traffic are desirable for operational reasons, care must be taken not to carry this too far and segregate the tramway from its customers. To provide access to an isolated tramway, especially if it is running in a cutting or above street level, could prove very expensive in construction costs and, when operating, in lost revenue.

Example of planning a route for access

Types of track

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