Approximately three years ago at a Winter Maintenance Management workshop in Canterbury it was agreed to investigate and identify "Best Practice" for Temporary Traffic Management (TTM) in respect to Winter Maintenance Operations which include, but are not limited to: snow clearing, ice gritting and road sweeping.
A working group of representatives from Transit New Zealand (Transit), Opus International Consultants, Fulton Hogan Ltd and Works Infrastructure Ltd was formed to identify best practice. The group found that, although the standards relating to Mobile Operations and Winter Maintenance Operations had not substantially changed since 1993 when Transit's Specification for Temporary Traffic Control - TNZ G/1 was used, the actual TTM methods used for Winter Maintenance Operations varied widely and that some were potentially safer / more compliant than others.
Following the identification of best practice a series of draft standard TMPs were produced in early 2005 and Fulton Hogan Canterbury tested these, and some new equipment, during that winter. The TMPs were also submitted to Transit's Code of Practice for Temporary Traffic Management (CoPTTM), Industry Review Group (IRG) meeting on 23 and 24 of June 2005 for their consideration and they identified:
the potentially high risks associated with this type of work which is often undertaken during adverse weather conditions, and
the difficulties associated with not having consistent temporary traffic management systems that inform road users of a hazard while at the same time allowing a contractor to treat the hazard as quickly as possible, to minimise the exposure of both Road Controlling Authorities and Contractors when / if things go wrong.
The IRG, while not in total agreement with the draft standard TMPs, decided that immediate action was required on a national basis to:
Investigate current TTM practice
identify and document best TTM practice
develop draft TMPs for industry consultation
finalise best practice TMPs, and
make the TMPs available to all via the Transit website.
As a result of the above Transit convened an IRG Winter Maintenance Best Practice sub-committee with representatives from:
Transit National Office
Transit Regional Office's
Consultants involved in Winter Maintenance Management - Opus International
Contractors involved in Winter Maintenance Operations - Fulton Hogan and Works Infrastructure
The sub-committee met on the 27 of January 2006 and the standard TMPs that resulted from the meeting, and subsequent industry consultation, can be downloaded from the Code of practice for temporary traffic management (CoPTTM) index page.
Winter Maintenance Operations are generally undertaken during adverse climatic conditions, to maintain as far as is reasonably practical, the safest possible road operating conditions. At these times, although both traffic volumes and vehicle speeds are likely to be lower than normal, the prompt and timely treatment of a potentially hazardous and/or dangerous road condition is a matter of urgency. However, treatment methods must take into account the need to:
The standard TMPs developed comply with the intent and requirements of CoPTTM and take into account the special requirements described above.
The downloaded standard TMPs need to have the relevant details added and then submitted to the appropriate Road Controlling Authority (RCA) and/or Engineer for approval.
It should be noted that these TMPs are not pre-approved and that the approval of the appropriate RCA and their Traffic Management Coordinator is required, and is not guaranteed.
Contractors and RCAs must be mindful that the TMPs will not cover every possible Winter Maintenance condition/activity and represent the minimum standard of 'Best Practice' for the majority of Winter Maintenance Operations. On certain roads, due to environmental and geometric constraints, other methods of TTM and /or additional equipment may be required. In such cases the RCA and the Contractor(s) should act on such local knowledge and agree on any enhancements that are required.
The LED 'DO NOT PASS' signs referred to in the TMPs for Snow Clearing on a Road (SC) and Grit Spreading (GS) must have the following build and operating details:
When the operator of the working vehicle deems that it is safe for following vehicles to pass, the LED sign is switched off, the working vehicle pulled over to the side of the road and the drivers of the following vehicles waved on. The photos below show details of the trial signs.