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Red Hill friction testing in 2014 may have overstated safety factor

Red Hill friction testing in 2014 may have overstated safety factor

The Ministry of Transportation was on the stand all last week at the Red Hill Valley inquiry providing largely technical evidence on the kinds of testing it undertook on its roads. Chris Rogers, now retired but in 2008 was manager of soils and aggregate section for MTO, expressed skepticism about some friction testing that was conducted on the Red Hill Expressway in 2014. “This is at 90 km/hr., he told commission counsel, “It (friction testing)was nearly always done at 100 kmh. And if we had tested this highway at 100 kmh., we would have gotten lower values, almost certainly than what you saw in 2014…so these values you are getting here are not values that I would be totally happy with.” Mr. Rogers was retired when the 2014 testing was done but he had decades of fiction testing experience prior to that.

Previous testimony and inquiry documents showed that while MTO was engaged in extensive testing of pavement for its highways in areas like friction and had established standards for its own construction activities, MTO jurisdiction did not extend to municipal roads such as the Red Hill Expressway. Earlier in the week Becca Lane who was a senior Pavement Engineer with MTO testified that the only reason MTO agreed to conduct friction testing on the Red Hill Expressway was because of Hamilton’s proximity to MTO headquarters in Toronto—that such testing was not generally available to municipalities further afield.  Enquiry documents also show that there was some interest in Hamilton’s project because of its use of Stone Mastic Asphalt (SMA) as its surface coat at the same time as MTO was closely studying the relatively new asphalt mix on its own highways.

Lane told the inquiry that MTO’s staffing had been severely cut during the 1990’s during the Harris era, and human resources were not adequate for MTO to do much more than see to its own needs.  In the area of friction testing, she told the inquiry that there was reluctance to set an absolute test score number for friction, partly out of fear of liability concerns, but generally speaking, a score of fn30 or above was seen as satisfactory. She also said that resources were so tight that if a highways project was considered low-risk that they would let the contractor decide on the type of pavement mix to use. She said there were three different levels of highways paving contracts—a three -year warranty, a five-year warranty and a seven-year warranty. She described a constant tension between MTO trying to ensure safety and longevity in its prescribing of methods and materials to be used in roadbuilding and the paving industry’s focus on costs and speed of completion of projects.

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