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T.P.D.M.V.2.4
(Al/2001)
4.2.9 Choice of Junction Type
4.2.9.1 Many junction choices will be constrained by obvious economic, environmental and
topographical considerations. The scope for weighty consideration of all the factors
mentioned in the previous sections may therefore not be possible. However choice of
junction type should encompass the examination of as many of these parameters as possible.
To aid the designer Table 4.2.10.1 briefly summarises how each junction type performs
against a list of the most important parameters. The table is perhaps of most use in
comparing the signal and roundabout types of junction layout which can cater for a similar
range of traffic flows.
4.2.9.2 In making the choice of junction type, it is also necessary to ensure consistency with the
surrounding road network. An obvious example is that a roundabout which otherwise
proves the most viable form of junction control when considered against other parameters,
should be avoided in an area which is controlled by A.T.C. Similarly on high speed roads,
traffic signals which require abrupt changes of speed should be avoided.