Collision detection

I could have got it as an option on my Subaru but it is now standard on some Nissan's. This includes emergency.

Cited article says dings give 5 seconds extra reaction time. Most places here call for a 3 second rule which means following distance should be 3 seconds when you reach where the vehicle ahead was when you start counting. Here in Delaware the law calls for 4 seconds.

Very few people pay attention to this rule.

On Wed, 4 Oct 2017 19:03:39 -0400, Frank coalesced the vapors of human experience into a viable and meaningful comprehension...

On Chicago area expressways, a 3-second following distance is an invitation for a car to cut in front of you and fill the void.

Five-second following distance and a gravel hauler (spilling gravel) will cut in.   LOL

Gonna happen soon according to this:

Soon is 2022.

I thought most modern cars had auto brakes.

It's 2 seconds in the UK (I guess we think faster). I usually leave 0.5 seconds, or 0.25 seconds if the guy in front is pissing me off. How on earth can anyone take 2 seconds to react? 2 seconds gap is very useful though for me to pull into.

We don't have drum brakes anymore. And we all have ABS.

At 5 mph a car will travel 7 ft per sec.

The warning is simply to alert the driver that the car is approaching something faster than it thinks is safe. At that point, it is for the driver to decide whether there is, in fact, any danger. Mine regularly warns me when I am going round a particular bend, whether there is a road sign on the outside of the bend. I can tell that there is no danger and no need to brake, but the car cannot. If I ignore the warning and continue to drive at speed towards an obstacle, then it will apply the brakes.

The car is just alerting the driver to stop texting, put down the phone and focus on driving the car into the impending accident.

Nor me. They're talking s**te.

It happens to someone, because if I see a "safety gap", I go into it.

Yes, this is how my car will act.

I had picked up this ruling when I last took an online defensive driving refresher course. Doing so results in 15% auto insurance cost reduction. The old rule was so many car lengths at certain speeds. We all know it takes 4 times as long to stop at double the speed so this rule makes it easy.

Like I said, few abide particularly on higher speed roads. I try to drive with the flow myself and know that leaving such distance is bound to get me cut off.

Best using your instincts instead of trying to calculate. You know how fast your reactions are, you know how good your brakes are. Almost everyone knows when they have to brake to avoid something in the road. You don't measure it, you just know.

Only if you don't press the brake. Then it will very quickly be doing 2mph.

If you're going by the highway code, it's based on drum brakes.

The problem with that is that the car might not have such a 360 view of the world as the driver. There's no point slamming on the brakes to avoid hitting say a mini in front if by doing so you're do so you're going to get a 40 tonner in your arse. In that scenario swerving and clipping the car in front would be a much better response but at the moment cars can't do that autonomously and even if they could they still might not have rear view cameras to make that assessment.

I guess it can help to wake up a sleepy driver, but from what I've seen on Youtube crashes, it's FAR too late a warning and happens AFTER the crash.

Plus, every one I've heard is a silly little ding noise. It doesn't sound urgent, it's just a noise like you'd get when you don't put your seatbelt on. I'd imagine the driver would be thinking, "I wonder what that noise is", checking the dashboard for a warning light, then misses looking out for the collision altogether. I'd call it a stupid distraction. It's like the passenger noticing the driver is going to crash and saying "Excuse me...." "Yes dear?" "See that truck in front, you'd better...... oh too late." A better system would be the passenger shouting "Look out!" or the car making a very loud warning noise, not "ping!"

I can't believe people actually attempt to measure a distance or time while driving. The safe distance should come naturally, and changes according to your reaction time, the condition of your car, the weather, if you can see through the car in front [1], etc, etc.