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T.P.D.M.V.2.4
(Al/2001)
4,2.10 Spacing of Junctions
4.2.10.1 By limiting the number of junctions along a route the number of points of capacity reduction
and high accident potential are similarly limited. Spacing of junctions should also have
regard to such matters as the length needed for right turning, speed change lanes and
weaving manoeuvres. It is recommended that the minimum spacing set out in Table 4.2.11.1
should be adopted and where practicable even greater distances should be used. For grade
separated intersections longer spacing will often be dictated by the simple summation of the
length of slip road and the merging, weaving and diverging requirements and it is unlikely
that junction centres will within 1 km of each other.
Table 4.2.10.1
Desirable Minimum Spacing between Junctions
Route Type
Spacing (metres)
Rural Trunk Roads 550
Urban Trunk Roads, Primary Distributors 300
District Distributors 200
Local Distributors 100
4.2.11 Signing and Lighting
4.2.11.1 The most elaborate and expensive junctions can be spoilt by poor signing and lighting and
the provision of these ancillary facilities should receive consideration at an early stage in the
design process. Badly located signs and lighting columns may impede visibility thereby
reducing capacity and increasing accident potential. The designer should therefore have
mind of the type and location of these facilities and ensure that his design provides space for
their installation.