DCAN 15: Vehicular Access Standards
Requirements for Trunk Roads
13.1 The Department has special additional requirements for accesses onto roads classified as trunk roads in order to comply with TD41/95: “Vehicular Access to All-Purpose Trunk Roads” set out in DMRB4 -Volume 6. Trunk roads are a subset of the network of designated main traffic routes. These requirements apply even when an access would otherwise be permitted under the main traffic routes policy contained in PPS31: “Development Control: Roads Considerations”.
13.2 A new access shall not normally be permitted in an overtaking section of single carriageway trunk roads as defined in TD 9/93: “Highway Link Design” set out in DMRB 4 - Volume 6.
13.3 A new access shall not normally be permitted where the trunk road gradient exceeds 4%. It is recognised that in hilly terrain accesses at locations with steeper gradients may sometimes be acceptable,particularly where the trunk road flows are in the bottom half of the range TD 20/85: “Traffic Flows and Carriageway Width Assessment” DMRB4 - Volume 5.
13.4 The gradient of an access onto a trunk road shall not exceed 10% other than in exceptional circumstances. The access gradient immediately next to the trunk road should be considerably less and a ‘dwell’ area of at least 15m provided immediately adjacent to the trunk road carriageway. Where site conditions are particularly difficult this area may be relaxed to 10m. In the case of a single or paired dwelling access it may be relaxed to 5m. The gradient for the dwell area shall lie between 0 and 2% on the approach downgrade. In difficult circumstances this may be increased to between + and - 4%. The intention is to prevent vehicles stalling on a mild hill when attempting to accept a gap in trunk road traffic or inadvertently rolling out into the trunk road carriageway.