Geometric Design of Major/Minor Priority Junctions

1 Geometric Design of major /MinorPriority JunctionsSummary:This Document gives advice and standards for the Geometric Design of major / minor Priority Junctions with regard to traffic operation and HIGHWAYS AGENCYTD 42/95 THE SCOTTISH OFFICE DEVELOPMENT DEPARTMENTTHE WELSH OFFICEY SWYDDFA GYMREIGTHE DEPARTMENT OF THE ENVIRONMENT FORNORTHERN IRELANDV olume 6 Section 2 Part 6 TD 42/95 Registration of AmendmentsELECTRONIC COPY - NOT FOR USE OUTSIDE THE AGENCYJ anuary 1995 PAPER COPIES OF THIS ELECTRONIC DOCUMENT ARE UNCONTROLLEDREGISTRATION OF AMENDMENTSA mendPage NoSignature & Date ofAmendPage

2 NoSignature & Date ofNoincorporation ofNoincorporation ofamendmentsamendmentsVolume 6 Section 2 Registration of AmendmentsPart 6 TD 42/95 ELECTRONIC COPY - NOT FOR USE OUTSIDE THE AGENCYPAPER COPIES OF THIS ELECTRONIC DOCUMENT ARE UNCONTROLLEDJ anuary 1995 REGISTRATION OF AMENDMENTSA mendPage NoSignature & Date ofAmendPage NoSignature & Date ofNoincorporation ofNoincorporation ofamendmentsamendmentsDESIGN MANUAL FOR ROADS AND BRIDGESELECTRONIC COPY - NOT FOR USE OUTSIDE THE AGENCYJ anuary 1995 PAPER COPIES OF THIS ELECTRONIC DOCUMENT ARE UNCONTROLLEDVOLUME 6 ROAD GEOMETRYSECTION 2 JUNCTIONSPART 6TD 42/95 Geometric Design OFMAJOR/ minor of Major/Minor Priority of Major/Minor Priority Users' Specific Design of Design 1 Calculation of CapacityAnnex 2 Design of Channelising IslandsVolume 6 Section 2 Chapter 1 Part 6 TD 42/95 IntroductionELECTRONIC COPY - NOT FOR USE OUTSIDE THE AGENCYJ anuary 1995 PAPER COPIES OF THIS ELECTRONIC DOCUMENT ARE UNCONTROLLED1 Standard shall be used forthwith onall schemes for the construction.

3 Improvement andmaintenance of trunk roads, currently beingprepared provided that, in the opinion of theOverseeing Organisations, this would not result insignificant additional expense or delay Organisations should confirm itsapplication to particular schemes with theOverseeing major road is the road to which isassigned a permanent Priority of traffic movementover that of the other road or minor road is a road which has to givepriority to the major three basic types of major /minorpriority junction on single carriageways are definedin the following junction .

4 A T- or staggeredjunction without any ghost or physical islands inthe major road, and without channelising islands inthe minor road approach (Fig 1/1).1. treatment of Major/Minor Priority junctionshas recently been the subject of a study sponsored bythe Department of Transport. This study reviewed theexisting advice given in Advice Note TA 20/84 on theLayout of Major/Minor Junctions , and maderecommendations on the amendments and additions tothe document based on research carried out since 1984,and on current good a result of the study.

5 This standard nowprovides details of the latest requirements andrecommendations on general Design principles andsafety aspects of the Geometric Design of major /minorpriority document replaces Advice Note TA20 on the selection of the mostappropriate form of junction is given in TA 30 ( ) and TA 23 (DMRB ). main changes and additions from TA20/84 can be summarised as requirements are mandatory ( - ). long articulated goods vehicle witha single rear axle trailer has been replaced as the DesignVehicle by the long articulated vehicle ( - ).

6 Standard layouts in TA 20/84 have beenreplaced by figures which illustrate the Design elementsand their Standard defines the main types ofmajor/ minor Priority junction which can be used on newand improved trunk is also given on the choice between thedifferent types of Major/Minor Priority junction , and onthe siting of such safety issues are outlined, as are thoseparticular Design issues relating to landscaping and thespecific requirements of road recommendations are given on thegeometric Design of the important elements of themajor/ minor Priority junction , and the way in which theindividual components can be brought together toproduce a good overall 1 Volume 6 Section 2 IntroductionPart 6 TD 42/95 ELECTRONIC COPY - NOT FOR USE OUTSIDE THE AGENCYPAPER COPIES OF THIS ELECTRONIC DOCUMENT ARE UNCONTROLLEDJ anuary 19951 Island junction .

7 An at-gradejunction, usually a T- or staggered junction , withinwhich an area is marked on the carriageway,shaped and located so as to direct traffic movement(Fig 1/2). Lane Dualling. An at-gradejunction, usually a T- or staggered junction , withinwhich central reservation islands are shaped andlocated so as to direct traffic movement (Fig 1/3). Figure 1/1 :Simple T- junction (paras , )Figure 1 / 2 : Ghost Island junction (para )Figure 1/3 : Single Lane Dualling (para )Volume 6 Section 2 Chapter 1 Part 6 TD 42/95 IntroductionELECTRONIC COPY - NOT FOR USE OUTSIDE THE AGENCYJ anuary 1995 PAPER COPIES OF THIS ELECTRONIC DOCUMENT ARE UNCONTROLLED1 addition, there are four An at-grade junction of tworoads that cross approximately at right angles (Fig1/4).

8 An at-grade junction of tworoads, at which the minor road joins the major roadapproximately at right angles (Fig 1/1). or Y- junction . An at-gradejunction of two roads, at which the minor roadapproaches the major road at an oblique angle andterminates at the junction (Fig 1/5). Junctions . An at-gradejunction of three roads, at which the major road iscontinuous through the junction , and the minorroads connect with the major road so as to formtwo opposed T- Junctions (Fig 1/6).Figure 1/4 : Crossroads (para )Figure 1/5 : Left Hand Splay Skew junction ( para )Figure 1/6 : Simple Right/Left Stagger (para )Chapter 1 Volume 6 Section 2 IntroductionPart 6 TD 42/95 ELECTRONIC COPY - NOT FOR USE OUTSIDE THE AGENCYPAPER COPIES OF THIS ELECTRONIC DOCUMENT ARE UNCONTROLLEDJ anuary 19951/4 Mandatory of this document which aremandatory standards which the OverseeingOrganisation expects in Design , are highlighted bybeing contained in boxes.

9 These are the sectionswith which the Design Organisation must complyor must have agreed a suitable departure with therelevant Overseeing Organisation. The remainderof the document contains advice and enlargementwhich is commended to designers for dificult circumstances, the DesignOrganisation may relax a mandatory standard setout in this document to that relating to the nextlowest Design speed step, unless this documentspecifically excludes it. However, in using anysuch relaxation, the Design Organisation shall givespecial attention to the effect this relaxation mayhave on the overall performance of the is particularly important in the situation wheretwo or more relaxtions are incorporated intodifferent components of the junction Design .

10 In allinstances of relaxations, the Design Organisationshall record the fact that a relaxation has been usedin the Design and the corresponding reasons for itsuse. On completion of the Design , the DesignOrganisation shall report all decisions to theOverseeing from Mandatory very exceptional situations OverseeingOrganisations may be prepared to agree toDepartures from Mandatory Standards where theseseem unachievable. Design Organisations faced bysuch situations and wishing to consider pursuingthis course shall discuss any such option at an earlystage in Design with the relevant OverseeingOrganisation.