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Segregation from Road Traffic
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
- 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
Types of track
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