What is relevant for a:
5.1 Truck intended for towing multiple trailers

• Volvo: we should avoid specific requirements for trucks, as far as possible; to avoid burden on truck driver (in-use requirements); It does not matter if the weight is distributed on one or two trailers, what matters for the truck is the weight (“60t on one or two trailers is still 60t”)
• DK does not agree; trucks able to tow several trailers should be safer than the ones able to tow only one trailer; e.g. EBS brakes, ESC, front under-run protection etc.
• Chair raises the question of a router on the trailer
• Knorr: should the truck display which trailer is failing, or only that one trailer behind is failing?
• Scania supports Volvo comment that total weight is the point, not how many trailers are behind (see Volvo comment above); it is not required that the truck shows which trailer is failing.
• BPW: are there any requirements regarding power supply dimensioning?
• Volvo: truck should warn that trailer braking is failing; no need to inform driver about which trailer is failing (this is diagnostics); “router” is a technical solution, UN R13 should express non-design restrictive requirements.
• NW believes it is of interest to differentiate which trailer is failing.
• NL: supports Volvo that what is important is the total weight, not the number of trailers; no need to know which trailer is failing; ideal solution is not to have a special tractor to tow several trailers.
• Reaction time is a question to be addressed.
• Wabco points out that “EBS” is used in the discussions, while this is not defined in UN R13. The real point is the “electric control line”.
• Scania: ESC is required by UN R13, not the electric control line; the electric control line could be required for towing trailers, not for trucks.
• Proposal from Wabco and FIN to get inspiration from other regulations: ADR in Australia, national regulations in EU, FMVSS etc.

• BPW: dolly is required to provide 50% brake rate, while semi-trailer is only 45%
• The question of what is a dolly is coming back: it is a centre-axle trailer; a tractor for semi-trailer, the front axle of a full-trailer…?
• Volvo; should we limit the scope of our discussions to a max number of trailers to simplify the issue? (e.g. “only” two semi-trailers)
• The chair agrees to the proposal and remind the TOR mentions only current and emerging solutions should be covered, not unpredictable far future, thus considering 2 semi-trailers is enough at this point.
• MAN and FIN: we should at least try to regulate dollies, so that they are type approved; there is kind of common agreement on this point.
• VBG supports: dolly must be kept in the scope.
• The definition of a dolly in CLEPA UN R13 proposal (“A dolly” is deemed to have one or more axles and is used to convert a semi-trailer to a full trailer.) is maybe valid for braking, but not for couplings: hinge drawbar and rigid drawbar dollies are different things etc.

• 1st day:
  • MAN: should we define/request ESC for dollies? Semi-trailer are required to have roll-over prevention; do we need directional control in a dolly?
  • Wabco believes roll-over on a dolly is enough; MAN agrees.
  • NL: should the towing trailer brake the trailer behind in case of ESC intervention?
  • No conclusion, this is an open issue to be dealt in the group.
• On 2nd day, the discussion goes further on the question of stability:
  • Some more background highlighted by the Chair (available on NVF web-site):
    • Presentation of John Aurell / Thomas Wadmann (Volvo trucks) study from 2007
    • DK mentions this study have been broadly used to set rules in DK for MVC
  • SWE gives some information about On-going work in Sweden
    • SWE mentions on-going work in Sweden to increase possible length above 25.25m, and possible weight as well.
    • Stability is a major item: the aim is to define a web-based tool to provide a calculation for stability; this is why it is interesting for SWE to look into different models existing; FIN would be ready to share some information on this particular item; However, stability of a complete combination does not fit in a type approval scheme for individual vehicles.
    • Discussions around requirements on ‘intrinsic stability vs stability systems”
  
  Conclusions: Keep the item open for further consideration by experts.