Vicroads Supplement to the Austroads Guide to Road Design Part 4B – Roundabouts
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VicRoads Supplement to Austroads Guide to Road Design – Part 4B VicRoads Supplement to the Austroads Guide to Road Design Part 4B – Roundabouts NOTE: This VicRoads Supplement must be read in conjunction with the Austroads Guide to Road Design. Reference to any VicRoads or other documentation refers to the latest version as publicly available on VicRoads website or other external source. Rev. 2.0 - July 2011 Part 4B – Page 1 VicRoads Supplement to Austroads Guide to Road Design – Part 4B VicRoads Supplement to the Austroads Guide to Road Design Updates Record Part 4B – Roundabouts Rev. No. Section/s Description of Authorised By Date Released Update Revision Rev. 1.0 Development of ED – Network and First Edition July 2010 Supplement Asset Planning Principal Advisor – Rev. 1.1 Minor changes to text, Various Design, Traffic & Oct 2010 references and layouts. Standards Principal Advisor – Rev. 2.0 Section 5.3.4 Multilane roundabouts Road Design, Traffic July 2011 Appendix C Roundabout entries & Standards COPYRIGHT © 2010 ROADS CORPORATION. The VicRoads Supplement to the Austroads Guide to Road Design provides additional This document is copyright. No part of it can information, clarification or jurisdiction be used, amended or reproduced by any specific design information and procedures process without written permission of the which may be used on works financed wholly Principal Road Design Engineer of the Roads or in part by funds from VicRoads beyond that Corporation Victoria. outlined in the Austroads Guide to Road Design guides. ISBN 978-0-7311-9155-0 Although this publication is believed to be correct at the time of printing, VicRoads does VRPIN 02667 not accept responsibility for any consequences arising from the information contained in it. People using the information This VicRoads Supplement has been should apply, and rely upon, their own skill developed by VicRoads Technical Consulting and judgement to the particular issue which and authorised by the Executive Director – they are considering. The procedures set out Network and Asset Planning. will be amended from time to time as found necessary. Rev. 2.0 - July 2011 Part 4B – Page 2 VicRoads Supplement to Austroads Guide to Road Design – Part 4B References AGRD – Austroads Guide to Road Design AGTM – Austroads Guide to Traffic Management GTEP – Guide to Traffic Engineering Practice (superseded) SD – Standard Drawings for Roadworks VRD/RDG – VicRoads Road Design Guidelines (superseded) Australian Standards (2010). AS1158: Lighting for roads and public spaces. Akcelik, R. (1991). Implementing roundabout and other unsignalised intersection analysis methods in SIDRA. Australian Road Research Board, WDTE91/002. Akcelik, R and Troutbeck, R. J. (1991). Implementation of the Australian Roundabout Analysis Method in SIDRA. In Highway Capacity and Level of Service, (Ed. U. Brannolte) Proceedings of the International Symposium on Highway Capacity, Karlsruhe Balkema Rotterdam July 1991. George, A. L. (1982). Estimation of geometric delay at a roundabout. Unpublished report to the CRB (now VicRoads). Middleton, G. (1990). Geometric delays at roundabouts. Roundabout and Unsignalised Intersection Workshop, Queensland University of Technology, November, (Ed. R.J. Troutbeck). Troutbeck, R. J. (1989). Evaluating the Performance of a Roundabout. Australian Road Research Board Special Report 45. Troutbeck, R.J. (1990). Traffic Interaction at Roundabouts, Proceedings 15th Australian Road Research Board Conference, Volume 15(5), pp. 17-42. VicRoads (2008). Lighting of Arterial Roads Policy. VicRoads (2009). Lighting of Freeways Policy. VicRoads (2010). Guidelines for Road Lighting Design, TCG006-2-2010. VicRoads (2010). The Installation of Street Lighting Installation, TCG006B-1-2003. VicRoads Traffic Engineering Manual Volume 1 – Traffic Management. VicRoads Traffic Engineering Manual Volume 2 – Signs and Markings. Rev. 2.0 - July 2011 Part 4B – Page 3 VicRoads Supplement to Austroads Guide to Road Design – Part 4B Rev. 2.0 - July 2011 Part 4B – Page 4 VicRoads Supplement to Austroads Guide to Road Design – Part 4B 1.0 Introduction 3.2 Sight Distance Criteria 3.2.3 Criterion 3 1.1 Purpose Note that an absolute minimum sight distance VicRoads has no supplementary comments for is used in Austroads Guide to Road Design this section. (AGRD) Part 4B, Figure 3.1. 3.2.4 Other Visibility Considerations 1.2 Scope of this Part To enhance the prominence of the VicRoads has no supplementary comments for roundabout, the kerbs on both the splitter this section. island and central island should be light coloured or painted white. VicRoads practice 1.3 Road Safety is to avoid the use of dark coloured kerbing. VicRoads has no supplementary comments for Where there is a tram or train crossing this section. incorporated into the roundabout, care needs to be taken to ensure that the negotiation 1.4 Road Design Objectives speeds are slower and that drivers are aware VicRoads has no supplementary comments for of the presence and the location of the rail or this section. tram tracks. Where railway tracks are involved, it is preferable to provide level 1.5 Traffic Management at crossing ‘Wig-Wag’ signals or ‘boom barriers’ in conjunction with the roundabout. Roundabouts On-street trams can be successfully VicRoads has no supplementary comments for incorporated into a roundabout. As the tracks this section. will pass through the central island, eliminating part of it, care needs to be taken 1.6 Safety performance of to ensure that residual central island remains Roundabouts large enough to be recognised. Electronic VicRoads has no supplementary comments for signs have been incorporated at complex this section. urban locations and to reinforce tram priority. 1.7 Traffic Capacity of Roundabouts 3.3 Truck Stopping Sight Distance Example calculations can be found in VicRoads has no supplementary comments for Appendix VA of this Supplement. this section. 1.8 Signalisation of Roundabout 4.0 Geometric Design VicRoads has no supplementary comments for The design method outlined in the AGRD Part this section. 4B has been adopted by VicRoads, however its use is relatively untested in Victoria. It is 1.9 Significant Change from the Guide known that there may be some to Traffic Engineering Practice – Part 6: issues/challenges that designers will Roundabouts encounter when developing designs - especially with incorporation of non VicRoads has no supplementary comments for perpendicular approaches and duplicated this section. carriageways at roundabout approaches and departures. 2.0 Design Principles and Guidance should be sought from VicRoads Procedure regarding the design of roundabouts on VicRoads has no supplementary comments for VicRoads managed arterial roads when using this section. this design method for complex roundabouts. Additional supporting information regarding 3.0 Sight Distance the use of the new Austroads design method will be included in future updates of this Supplement as further experience is 3.1 Introduction developed. VicRoads has no supplementary comments for It should be noted that use of the new this section. Austroads method generally results in larger diameter roundabouts than previous design Rev. 2.0 - July 2011 Part 4B – Page 5 VicRoads Supplement to Austroads Guide to Road Design – Part 4B methods, especially in lower speed 4.5 Entry Geometry environments. If there are site constraints VicRoads has no supplementary comments for that restrict the use of the new Austroads this section. design method, VicRoads (the client or contract superintendent) should be consulted 4.6 Circulating Carriageway regarding the development of an acceptable solution. 4.6.1 Design Vehicle and Vehicle Swept Paths 4.1 Introduction To cater for vehicles that only occasionally VicRoads has no supplementary comments for use the roundabout, it may be acceptable for this section. these vehicles (i.e. checking vehicle) to use multiple lanes to make their turn. The road 4.2 Number of Legs authority should be consulted regarding the appropriate checking vehicle to be used if this VicRoads has no supplementary comments for is not specified. this section. 4.6.3 Encroachment Areas 4.3 Number of Entry, Circulating and Aprons shall not be adopted on the outside Exit Lanes the circulating carriageways of roundabouts to assist larger vehicles making right turns, 4.3.1 Number of Circulating Lanes as this allows for higher speeds through the roundabout by cars. Other design changes Correction should be made to ensure the vehicle can The first sentence “The number of circulating make this movement on the circulating lanes from any particular approach must be pavement. equal to or greater than the number of entry lanes on that approach” is not correct and 4.7 Exit Curves should read: VicRoads has no supplementary comments for “The number of circulating lanes is this section. determined by the number of through lanes on the approach and also considering the 4.8 Entry and Exit Widths right turn movements from the preceding VicRoads has no supplementary comments for approach.” this section. 4.4 Central Island 4.9 Separation between Legs 4.4.2 Factors Affecting Central Island VicRoads has no supplementary comments for Size this section. Additional Information 4.10 Superelevation, Gradient and Roundabouts with a larger inscribed diameter, Drainage and consequently a larger central island, have a slightly greater entry capacity. In general, VicRoads has no supplementary comments for a large central island provides greater this section. separation