The other thing to factor in is the reaction time. When the lead car brakes the next car brakes a fraction of a second later and has to brake a little harder because to stop before hitting the lead car. The next car in line has to brake harder still if you have a long enough convoy of traffic you eventually reach a point in the line where it is impossible for the next car to break hard enough to avoid a collision. The ideal situations are either wide enough gaps that any car can stop in time irrespective of how hard the lead car brakes or short enough convoys that the rear most car still has enough stopping time when all the reaction times are subtracted.

This assumes that the data that the navigator has is good. I was recently driving in a 45 zone and the GPS went nuts telling me to slow down all the time. I found out later that the road had been improved over a year ago with extra lanes, a median and an increased limit.Similarly our local interstates had a speed increase to 70 bu there are still stretches at 55 and 65. Relying on the GPS data would be a nightmare.

Bingo! Yes, exactly what I thought. When I got one about a "flash flood warning" it scared the wife and kids and was for an area a hundred miles away. State wide alerts should be for state wide emergencies.

This could have been useful but it is so badly executed that I turned it off. I asked around and it turns out so did everyone else I spoke to. My first alert was a week or so ago in the middle of a thunder storm. We get many storms at this time of year and this wasn't particularly bad. Suddenly all four iPhones in the house started screeching the emergency alert tone. Scared the kids shitless. What we got was a "flash flood warning" that had already, and more subtly, been noted on Wunderground and Weather.com Apps. Worse it was a warning for an area a hundred miles from here. Weirdly we were watching TV at the time and there was no alert on the TV screen so I don't see why it went out to the phones. We've had a couple since and each time it has been for something that I wouldn't class as an emergency requiring such an intrusive alert but was also only relevant miles away from where I am.

There is an old story about a kid that cries wolf so many times that people start to ignore him.

...not holding my breath though.

Verizon FiOS currently has me over a barrel. My family watch shows on only a handful of the 200+ (probably 300 or 400 by now) channels that I'm paying for. Of the three channels we watch most, say A, B, and C to protect the innocent, the lowest tier of FiOS has none. The second tier has A but not B or C. The next tier has B and C but not A. The third tier has A, B and C. So I have to pay for next to the top most expensive tier to get the three channels. Add to that the fact that to watch it I have to rent a couple of "set top boxes" (quotes because it's under the set because you can't balance it on top of a flat screen) despite both TVs having perfectly good digital tuners sitting unused. Why do I need a decoder box when they have a huge box bolted to the side of the house? Can't they decode it in that and let me use my own TV tuner?

Does 100 miles from the border also imply 100 miles from the coast? If so that covers most major population centers on the East and West coasts.

Firstly, I have nothing against Apple. I bought my first Mac, a Mac Plus in 1985 and I've owned one or more ever since. I find the current track that Apple is following to be very disturbing. Apple always used to be about the customer experience but that seems to be dead and gone. Yes, there was/is a security hole in the Java plugin but completely disabling the plugin is NOT a customer friendly solution and is disproportionate to the risk. Despite the vulnerability I have yet to hear of ANYONE who has been the victim on a Mac. Despite this Apple disabled a plugin that is critical to many people ranging from people running games like Runescape to companies who have legacy point of sale and inventory systems that use Java applets to access database backends. What is next? Disable Flash because of "security risks" what about OSX Applications? They are already forcing sandboxing and draconian rules on developers wanting to sell via the App store.

Keep this up and this is one Apple customer who is going to be looking for alternatives, and where there is one there are probably many.

" How Can I Protect My Android Devices From Hackers?"

Simple, don't turn them on.

Since I was born in 1960 my high school computer lab was very interesting. We had cards with little ovals on them and a soft pencil. We wrote our Fortran or Basic program on paper in a notepad until we thought we had it right then copied each line to a card by shading in the appropriate oval with pencil. The cars were sent off to a nearby college which had a mainframe. The hand filled out cards were passed through a reader that generated punched cards. We got the cards back the next day and corrected errors by hand using a light blocking sticky tape to cover holes in the right place and a hand operated punch to make new holes. The punched cards were shipped off and read in to generate a printout of the program that was shipped back with the cards. We compared the printout with what we originally wrote and if it checked out the cards were shipped back and the program executed. We got back the cards and the result of the execution in the form of more line printer output. If there were no syntax errors and all went well it was the best part of a week between starting to write the code and getting the execution results back.

Nothing like a little instant gratification...

This is such an obvious idea that it isn't right that it should be patentable. There are only a few ways of slowing an orbiting object down so that it de-orbits. The way nature does it is by putting gas in the way, called the atmosphere.

And the orbiter's stare, though there was no air,
Gave proof through the night that our flag was still there;

Yes you are missing something. If the sea water was of exactly the same density, which varies with salinity and temperature, and was dead calm, and the rock under the sea was a uniform density so gravity was the same everywhere then what you say is true. Also the sea bed rises and falls too. Just off the East coast shore, we have the Gulf Stream which is a flow of warm, and therefore less dense water moving North. Not only is it moving North but the East coast juts out and it has to flow around the coast. So, the sea level at Cape Hatteras (where the East coast juts out the most) is a complicated combination of the mean sea level, the mean gravitational pull at that point, the flow of the Gulf Stream and probably 1001 other things.

What the article is saying is that MEASUREMENTS show that the sea level there has risen three times more than the world average. If you subtract from that the known motion of the sea bed and various other known contributions to the rise you are left with something unusual that needs explaining. The best explanation that fits the facts is that the difference is due to the Gulf Stream. That is particularly worrying because any change in the Gulf Stream is a big deal.

The problem with TV advertising is that it's like firing a shotgun into a crowd. You know you're going to hit someone but whether it's the right someone is, literally, hit and miss. In the good old days (if they ever existed) the products advertised were relevant to a large fraction of the population and the hit to miss ratio was high. Now most of the advertising is for cars that I can't afford, investment banks (you have to have something to invest!), drugs with terrible side effects for diseases that I don't have etc etc. I'd have to view hours of advertising to see the one or two that are relevant to my lifestyle.

Ok, the cable companies make money from advertising, I get that, but forcing me to watch irrelevant advertising is a waste of everyone's time.

It's so miserable dark and cold for half the year that there's nothing else to do in Canada.

Sometimes I read a comment and think, I wish I'd written that!

Well done Sir.