Clearly someone has read Highlands proposal (and thanks for your contribution)
One other interesting oversight to consider....
The traffic study uses a "worst" case scenario ("worst" for us, "best" for Highlands!) that puts 150 trucks per hour in and 150 trucks per hour out of the quarry, 24 hours per day, seven days per week AVERAGE.
Now I have seen enough of the construction industry in the GTA, at all hours of the day, for every day of the week, to know that there are not many project sites that work 24 hours per day, and even fewer that will work on a Sunday. There are not that many aggregate- hauling truckers that run through the night, whether it is a larger firm or an independent, since there is no active site to ship to. So I would expect that there would be a much larger volume of trucks during the day than their study puts forward to come up with a daily average of 150 per hour.
Another thought... there is no firm figure of tonnage expected to be shipped in the report. They give the figure 10 million tonnes at one point (which would give the quarry a 100 year lifespan according to their reserve estimates and I would guess that this figure would be excessively long timeframe even for the shrewdest hardcore, yet still mortal, capitalist), but say that the amount shipped will be market-driven, hence the seeking of an "unlimited" license. The traffic study does open the door to more trucks on the road saying that if the PEAK hour volume exceeds 150 trucks, then intersection improvements and road widening will be necessary along #124 down to #89.
150 trucks per hour average each carrying 40 tons would be a 52 million tonnes per year output which would give the quarry a 20 year lifespan, which would certainly be a more agreeable timeframe for a greedy investor.