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Size does matter - but when is big too big?


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Derrick Hitchins

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Size does matter - but when is big too big?

  1. 1. SIZE DOES MATTER – BUT WHEN IS BIG TOO BIG? Derrick Hitchins, SMEC Australia 2016 AITPM National Conference, Sydney, July 2016 1
  2. 2. • New vehicle designs offer significant advantages to commercial freight operators in terms of volume and payload. • For this reason it is inevitable that the industry will continue to call for a change to the rules and regulations that govern them. • In response, state road authorities and enforcement agencies have to continue to modify their standards and guidelines with respect to the operation of those vehicles • It is therefore imperative that we as traffic engineers become more familiar with the needs of this ever-changing heavy vehicle fleet. Introduction 2
  3. 3. A. How big is Big ? B. Road Access Arrangements C. Treatment of high-productivity vehicles in Queensland D. Understanding the impact of these larger vehicles on our roads E. How should traffic engineers and planners respond Presentation Overview 3
  4. 4. General Access Vehicles A. How big is Big ? 4 • B-double (19m max) • Do not require a notice or permit to operate on the road network • Have general access to the road network unless the road is sign-posted otherwise
  5. 5. Prime mover towing two semi-trailers connected by a drawbar Type 1 Road Trains (36.5m max) 5 B-triple AB-triple
  6. 6. Type 2 Road Trains (53.5m max) 6 BAB-quad ABB-quad Prime mover towing three semitrailers connected by drawbars Rigid truck towing two semitrailers connected by a drawbar
  7. 7. But when is big is too Big ? 7
  8. 8. Productivity Benefits Quantified 8Source: Moving Freight: An update on road network freight access
  9. 9. Heavy Vehicle National Law (Commonwealth of Australia) • Governs the use of B-doubles in stated areas, on stated routes, during stated hours of stated days and under stated conditions. • The NHVR liaises directly with road managers to manage applications and issue permits. For General Access Vehicles (i.e. < 19m) • Road managers provide pre-approved consent for a range of approved heavy vehicle routes • In turn, Austroads (2009) guidelines for Arterial Roads requires designers to – Design for 19m vehicles and check for 25m e.g. B-double B. Road Access Arrangements 9
  10. 10. B-double (23m-25m-27.5m max) NHVR Class 2 Heavy Vehicles - Notice or permits must issued by National Heavy Vehicle Regulator (NHVR). 10 A-double (36.5m max) B-triple (53.5m max) Restricted Access Vehicles
  11. 11. • PBS is an alternative regulatory scheme for heavy vehicles that was developed throughout the 2000s in order to meet the demands of the growing road freight task and allow more widespread adoption of higher productivity vehicles. • It was initially trialed by jurisdictions and subsequently formally adopted by the National Transport Commission (NTC) in a regulatory sense in 2011. • The standard seeks to achieve: – a more sustainable transport system through improved road vehicle regulations – a more flexible road transport regulatory environment that allows for greater innovation in vehicle design Performance Based Standard 11
  12. 12. C. Treatment of high-productivity vehicles in Queensland 12 • Department of Transport and Main Roads publishes a set of maps via their website (same for all other States) • Direct translation between the existing Restricted Vehicle Access conditions and roads classified under PBS.
  13. 13. • To begin with, the applicant needs to consult with the relevant road authorities to discuss the likelihood of being granted road network access • Only accredited PBS assessors can submit PBS Design applications to the NHVR. Includes investigation of road network access to design development stage. • Onus is on the applicant to prove suitability of the proposed vehicle design as well as the associated vehicle mass, bridge loadings and the level of PBS network compliance. • Funding of infrastructure improvements by PBS applicant is considered on a case by case basis. • Only after PBS vehicle approval can applicant apply for a permit with the NHVR. PBS Road Access Application 13
  14. 14. PBS Class B categories provide for longer than current general access, B-double, Type 1 and Type 2 road train combinations. This means: • Longer storage lane lengths at intersections; • Longer signal timing for left or right turns at intersections; • Increased overtaking provisions on rural roads; • Increased enforcement bays and rest area sizes; • More stacking distance at railway level crossings; • Larger radius swept paths and median openings • Greater impact on last mile constraints. PBS Class B network 14
  15. 15. 15 • The B double is currently Australia’s safest and most efficient mainstream heavy freight vehicle. • Reasons include – Better driver education – safer performance of larger vehicles – increased levels of enforcement – Greater participation in the Intelligent Access Program (IAP) D. Understanding the impact of these larger vehicles on our roads
  16. 16. • Less heavy vehicles on our roads • More efficient movement of freight • Increased payload capacities, especially for minerals and grain 16 • Intersection geometry • Pavement loading • Bridge loading • Road width requirements • Actual road wear PRO’s CON’s So why all the fuss ?
  17. 17. Intersection geometry 17 • Low speed swept path impact on existing intersections most common shortcoming. • Mitigation includes: – Pavement widening – Additional line marking / painted islands – Roadside furniture set back
  18. 18. Pavement loading (1/2) 18 Maximum mass (tonnes) permitted under GML Maximum mass (tonnes) permitted under HML Single drive axles on buses 9.0 t 10.0 t Six-tyred tandem axle groups 13.0 t 14.0 t Tandem axle group 16.5 t 17.0 t Tri-axle group 20.0 t 22.5 t
  19. 19. Pavement loading (2/2) 19
  20. 20. Bridge loading 20 • Bridges also need to withstand the amplified effects of dynamic loading, over-loading, vertical and horizontal shock forces such as in areas where heavy vehicle braking occurs. • From a structural perspective, heavier payloads do not necessarily relate to greater relative bridge impacts. • This is because in some instances the longer vehicle types are able to spread their axle loads more evenly across the structure or even bridge a short span length.
  21. 21. Road width requirements 21 • This measure considers the vehicle’s ability to remain within the available traffic lane width along a straight road. • This measure is influenced by variations in the road surface due to cross-fall, unevenness and localised failures on occasion. • Mitigation: – increase the available lane width or – construct a surfaced shoulder
  22. 22. Recent Survey Results 22 • Consistent with previous studies • Main findings relate to: – road lane width and – road surface condition • As perceived by the motoring public (as opposed to engineers)
  23. 23. Actual road wear 23
  24. 24. E. How should traffic engineers and planners respond 24 • Road Controlling Authorities and Councils are under severe pressure to maintain the condition of our roads. This effort may be diverting funding away from other areas of greater need. • The advent of larger vehicles have the potential change many of our previous assumptions about vehicle performance and how they impact on our roads. • More needs to be done towards encouraging the use of the right size of vehicle for the right size of job, especially if there a viable parallel alternative available, such as rail. • Bigger trucks might be more efficient, but they are also having an impact on the behaviour of other drivers and the perceived level of safety associated with the driving task when combined with other smaller vehicle types.
  25. 25. Banora Point Upgrade, New South Wales, Australia Thank you DERRICK HITCHINS National Sector Leader Traffic and Transport Planning, SMEC Australia Pty Ltd ADAM RITZINGER Senior Engineer, Advantia Transport Consulting Pty Ltd