Skip Navigation

You're viewing a single thread.

173 comments

  • 99% of traffic like this is caused by people following too closely.

    • Yeah ideally you put 3 seconds between you and the car in front of you. Gives a nice, springy cushion to not brake as much. Your mechanic will also be surprised how much longer your brakes last.

      • I've always said that if you're using your brakes on the highway and it's not for an emergency stop, you're too close to the car in front of you. Even if they're the type that are on and off the brake constantly, if their speed isn't changing much you shouldn't need to follow their example. Of course I try to get out from behind them because they are like crying wolf and one of those brakes might be for real.

        When caught in a traffic jam I look for a semi to get behind. They won't accelerate fast like some car drivers do, and they don't stop as fast either. Plus they can see better if things area really starting to move or not. Keep a few car lengths behind them and while everyone is doing the start and stop motions, I'm keeping a slow but steady speed usually without needing to brake at all. It's also less stressful.

      • Too many people were taught, and still teach, the "two car's length" rule. Which is awful. 2 to 3 seconds is much better and intuitive to figure out.

        You say 3, which is great, but I'd settle for 2. Most people on the highways around me leave more like 0.5; I sincerely think the vast majority of people greatly overestimate the amount of space in front of them to the next car.

        • Two car lengths is ridiculously close. The average car is approx. 4.5m in length. Two car lengths is 9m. The average human reaction speed to visual stimuli is approx 250 milliseconds. At 100 km/h (28 m/s) you would travel 7 metres in that time, and that's just the time for you to notice the stimulus and react, not to choose an appropriate action. If you're 2 car lengths behind and the car in front of you brakes hard, you're going to hit it.

          2 seconds behind is 56 metres behind, or 12.5 car lengths. 3 seconds is 18.5 car lengths. Even 0.5 seconds is 3 car lengths. Not enough to safely react to the car in front of you doing something unexpected, but not the tailgating that 2 car lengths implies.

      • If you're in traffic (i.e. if you are part of the traffic) and you leave a 3 second gap between you and the car in front of you, another car will drive into that gap. If you back off to create another 3 second gap, it will happen again. Even worse, if you hit the brakes to create that three second gap, even if it's very lightly, you might cause an even worse traffic jam behind you.

        I would prefer to leave a big gap to the traffic in front of me, but in many cases 3 seconds simply isn't practical. A car merging into the lane in front of you is inherently more dangerous than a car already being in that lane. If you keep trying to maintain a 3 second gap in heavy traffic, not only do you put yourself in more danger as you keep having cars merging in front of you, you also cause more danger to the drivers behind you by constantly backing off or braking to try to maintain a gap.

        It would be absolutely wonderful if everybody believed in the 3 second rule. Traffic would flow so much more smoothly. But, apparently that isn't human nature. And, if you keep fighting for that gap when nobody else believes in it, you can actually make things less safe for yourself and for others.

        • If you're still moving with traffic, why do you care that someone got in front of you? If you're slowing so much that lots of people are getting in front at one time, then you're the obstacle. A 3 second gap changes with speed, if it's slow traffic that's less than a car length. And if some asshole muscles their way into a gap unsafely, let them. You'll still get to your destination far faster than if you hit each other or cause some road rage stupidity because of who is in front.

          Driving brings out the worst in people for no gain at all.

          • If you're still moving with traffic, why do you care that someone got in front of you?

            Because you no longer have a 3 second gap so you can no longer safely react to something happening in front of you.

            If you're slowing so much that lots of people are getting in front at one time, then you're the obstacle.

            That's my point. If you keep trying to make a 3 second gap and it keeps being filled in, you're going to cause a traffic problem.

            A 3 second gap changes with speed, if it's slow traffic that's less than a car length

            Technically, sure. If you're driving at less than 5 km/h and people on foot are passing you, then yes, you can have a 3 second gap with less than 1 car length. But, if you're driving at less than 5 km/h are you really driving, or are you effectively stopped in traffic?

            • If all these people are merging in front of you, then the adjacent lanes are moving a lot better, which is helpful for traffic. Less braking is the goal, and if 2 or more lanes aren't braking as much because you left some space in front of you, then traffic should flow much better.

        • "if you leave a 3 second gap, there will be enough space for others to safely merge into that space as they need to"

          • And after they do, there will no longer be a 3 second gap, and you're now driving too close to the person in front of you.

            • You don't have to brake and maintain a hard 3 seconds between gap. Just let off the gas a bit let it slowly restore itself. That gap is there so cars can move in and out as freely as they need.

              • Depends on how aggressively someone merges in front of you, and what they do once they're in your lane. Some people will merge way too closely. Some people will merge then slow down suddenly. Sometimes you do need to brake.

                • If they merge in your lane and then brake, then thats on them, not you. Yes, you will have to brake, but its not you that is being the bad driver. Just create more space between you and the car in front of you again.

                  You could also look into merging into a different lane temporarily until space is restored.

                  • It may be "on them, not you", but if it keeps happening because of the way you're driving, then fundamentally it's on you.

                    The fact is, if someone drives too differently from other drivers they make things less safe for everyone. It doesn't matter that if everyone adopted their way of driving it would be safer. It's still the case that driving too differently endangers everyone else.

                    In some cases, leaving a 3 second gap is going to cause more dangerous conditions than it alleviates. That's especially true if you're really rigorous about that 3 second gap and noticeably slow down to create a new gap when someone merges in front of you.

                    • You don't have to rigorously slow down though. Just ease it into existence. Its not a race. It might take a few seconds to replace that space, but thats fine. You don't even need to hit the brakes 95% of the time. Just go a mph or two slower and let it balloon out over time.

                      The person behind you can usually recognize that someone just whipped out in front of you and will give you some grace time to adjust.

                      And keep in mind, if someone is merging into your lane, then whatever lane they came from now has additional space, which lets those lanes work better. Its a win win.

173 comments