And that's different from your post, how? I've at least provided examples and a logical conclusion to those examples based on my experience behind the wheel.
"Very typical of an engineer" you say, and perhaps you're right. After all, the Canadian Courts recognize the opinion of a Registered Professional Engineer that is discussing a topic which he is considered an expert (I claim neither that I'm a registered professional nor an expert in this field). Do me a favour and put your bias against engineers aside for the duration of our debate... or not at all for all I care. If your only counter argument is a shot against my profession, there's no point in me responding.
Environmental. If memory serves me correctly, the speed limit was dropped during the fuel crisis as a way of reducing fuel consumption. This makes sense as the power required to overcome drag is a function of the CUBE of the velocity. That means that going from 70mph to 62mph actually decreased the power required to travel the speed limit by ~30% (1-(62/70)^3). But, going UP from 62mph to 70mph would mean an increase in power requirements of about 44% (70/62)^3. Obviously that doesn't linearly correlate to fuel consumption since there are MANY more factors (e.g. gearing, BSFC) to take into consideration. With most US states in the 65mph - 80mph range, it makes sense that auto manufacturers are gearing their vehicles for optimal fuel consumption at those speeds, so perhaps moving up to 70 mph, we won't see drastic increase in fuel consumption... But however you look at it, there will be an increase in fuel consumption and emissions. So from an environmental standpoint, there's a good reason NOT to raise the speed limit.
Safety. Anyone care to share any studies about the states that went from 55mph to 70+ mph? I'm guessing safety did not decrease (and if it did, not by much). Unless safety increased with the increase of speed, I don't see the speed argument being a supporting argument either way. For the politicians to consider the change, the safety increase would have to be somewhat substantial.
Cost. Yes, there's a cost involved with increasing the speed limit. If there's no real benefit to that cost, it's wasted money. So what is the benefit? I get to work sooner? I get to my destination sooner?
I'm not opposed to higher speed limits. But I'll be the first to admit that my desire for raising the limit is purely selfish. For the politicians to consider an increase in speed, there has to be a selling point... What's the selling point? The only arguments presented in favour of increasing the limit was that it's a "more reasonable level" (what makes it more reasonable?) and "so we don't get ticketed at 130km/h" (so, don't drive at 130km/h).
This is the most logical post by far. To add to it, my own question would be how this idea of an increase would correlate to the demographic on our highways, not whether or not it works elsewhere in the world. Weather is a factor here, as is the sheer volume and variety if traffic (the 400 series are some of the highest traveled highways in North america). I can accept that on either end of the less populated 401 would be a candidate for the increase, but would counter that the volume of truck traffic is also substantially higher in those areas. I've used these corridors extensively, and the difference in truck speeds and especially the hills to the East would be a problem.