With regards to the proximity of the 401 highway. Irrespective of whether it was there before the runway was extended or not, building a bridge over the ravine, containing a sand trap would not have been difficult. Then the enviros would have their ravine and a/c would have a saftey feature worth having.
One 'expert' I heard on BBC 24 News said how the modern a/c are so much safer as they are built much more strongly than previous generations. If memory serves (pax memory
) the VC10 and 707 were heavier and stronger for withstanding a crash than a 777 or 340. Or would the extra mass have made decleration more difficult??