Road surface friction data at the junction between the Lincoln Alexander and the Red Hill Valley Parkway appears to be strange, at best. Before concluding anything there needs to be an explanation.
There has been much uproar over the revelation that a report of testing performed by Tradewinds Scientific in 2013 on the surface of the Red Hill Valley Parkway in Hamilton seemed to have been hidden from the public. That issue may be resolved through some form of investigation. Meanwhile a review of the data contained in the report shows some peculiar results.
The main point deduced from the report is that the road friction values along the Red Hill Valley Parkway appear to be lower than those of the Lincoln Alexander Parkway. The friction data of the Red Hill is also below the recommendations set by research conducted in the United Kingdom. But looking at the details leads to some questions about the peculiar results.
For example, the figure below is taken from the Tradewinds Scientific report and shows the values of friction obtained along the Lincoln Alexander Parkway. The data at the far right of the graph is just before it turns into the Red Hill Valley Parkway.
Along the bottom of the figure we can see the distance along which the testing is conducted. So the values go from “0” at the start of the testing to past “9000” metres. It is difficult to determine where the end of the testing is located because the authors have not placed a marker at the end of the graph as they did at the beginning. However one can count the tick marks past the “9000” marker and it would appear that the “10000 ” metre marker would exist at the very end of the graph. The format of the figure would imply that the data approaches the “10000” or 10 kilometre mark as the Lincoln Alexander begins to be named the Red Hill Valley Parkway. So it makes sense to the viewer that the authors truncated this figure at the point where the Lincoln Alexander transitions to the Red Hill. The green line represents the recommended value of “48” and the data is above the recommendation up to the “10000” location of the graph.
However, the next figure shows the data for the Red Hill Valley Parkway. Is there not something strange here?
This Red Hill data is just an extension of the Lincoln Alexander data. This conclusion must be drawn because of another figure (“Figure 2”) in the Tradewinds report which is reproduced below.
The caption for that figure reads that testing was performed along the Lincoln Alexander from “A to B” and then along the Red Hill from “B to C”. So the “B” notation is referring to the same location where the Lincoln Alexander testing ends and the Red Hill testing begins.
And this understanding is verified by how the distance is labelled in the figure for the Red Hill data. One can see that it starts at the “10000” marker and this is the same location where the previous graph ended. But look at the purple line that is supposed to show the data from the left wheel location in the left lane. Look back on the first figure and note that at the unmarked “10000” location the friction value was something around “55”. Then returning to the figure of the Red Hill data, at the “10000” marker, the friction shows a value of about “35”. In other words, there are two very different friction values shown for the same “10000” metre location.
One might say that there is a misunderstanding about where the Lincoln Alexander data in the first figure ends. Perhaps it ends at “9900” metres and not at “10000” metres. But even if that were the case, a drop in friction from about 55 to about 35 would have to occur in about 100 metres. Is it a coincidence that the friction values seem rather constant until the specific point where one figure transitions into the other?
With respect to the right wheel path in the right lane, the figures depict this as as the blue line. Again, looking at the first figure for the Lincoln Alexander the data are all above the “48” recommendation. This seems to continue into the first few hundred metres shown for the Red Hill data. Then there is a sudden drop in about 200 metres from about “50” to about “32”.
The previous Director of Engineering, Mr. Gary Moore, was quoted as indicating that these data were inconclusive. While it is possible that the Tradewinds data may contain some unexplained error, this data cannot be described as inconclusive without some technical basis for supporting that description. The data provide a strong indication that something very unusual existed at the point of transition between the Lincoln Alexander and the Red Hill data. The location of that transition needs to be examined in more detail to determine whether it reflects the actual location where the surface of the Lincoln Alexander terminated and the laying of the new surface for the Red Hill started.
So when Mr. Moore referred to the Tradewinds data as inconclusive is that because he had a further basis to make that conclusion? It was reported in the news media that other friction testing was conducted by the Ontario Ministry of Transportation (MTO) but the report of that testing had not bee made public. So did the MTO testing contain results that disputed the Tradewinds results? Is this why Mr. Moore referred to the data as inconclusive? We do not know. However these are some of the many details that need to be uncovered.
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