Following distances

[MontanaMark]

I was recently driving (yes I do that now and then) my car on a major thoroughfare that has a lane in each direction and a center turn lane. I saw a pickup truck coming in the opposite direction and when he passed me, I saw a girl on a scooter right behind him. She was so close to his tailgate that I didn't even see her until he was almost right next to me. Traffic was fairly heavy, other cars were coming in the same direction as the truck and scooter

 

If I have been making a left turn, I may possibly have hit her.

 

So this reminded me that I need to leave extra room when following a large vehicle that can limit sight lines for opposing drivers. I know that I get in a hurry at times and cozy up to the guy in front, but now I'm making a conscious effort to hang back, relax and enjoy the ride.

 

Just thought I'd share my revelation with you all.

 

Cheers,

Mark

[szurszewski]

A great thing to remember for sure.

 

It's especially hard to see a bike if it not only follows closely but also positions itself to the center or right side of the lane. Assuming the condition of the road allows, I try to remember to put myself in a place that gives other traffic the best chance of seeing me.

[RPG]

good point. On my 120 mile/day commute, I remind myself to stay back, trying to be conscious of the rage that a cager might have seeing me too close in his mirror. I know how I get nervous when the cagers are on my tail at 80mph.

 

We all need to slow down a bit sometimes, enjoy the scenery and remember how lovely it is to be either behind the wheel or better yet, on two wheels.

 

RPG

[russell_bynum]

Assuming the condition of the road allows, I try to remember to put myself in a place that gives other traffic the best chance of seeing me.

 

I'm OK if other traffic sees me, but the main reason I do that is so that I can see what's going on.

 

And never, ever, ever ride in the middle of the lane following another vehicle. Anytime I see that, I give the rider a wide berth because I know they don't know what they're doing.

[Joe Frickin' Friday]

I'm OK if other traffic sees me, but the main reason I do that is so that I can see what's going on.

 

Appropriate lane positioning (both laterally and in terms of following distance) facilitates conspiciuity and visibility, a win-win.

 

And never, ever, ever ride in the middle of the lane following another vehicle. Anytime I see that, I give the rider a wide berth because I know they don't know what they're doing.

 

I cringe whenever I see that.

[russell_bynum]

I'm OK if other traffic sees me, but the main reason I do that is so that I can see what's going on.

 

Appropriate lane positioning (both laterally and in terms of following distance) facilitates conspiciuity and visibility, a win-win.

 

I agree...and that's why I said I'm OK if they see me. But that's not my primary goal since I'm going to assume they don't see me anyway.

[EddyQ]

I agree with all here in this post. However, when traffic becomes particularly busy and stressful, you better not leave much space in front of you. Someone who is itching to burn some stress will cut in front of you leaving no space and then hit the breaks.

[szurszewski]

I agree with all here in this post. However, when traffic becomes particularly busy and stressful, you better not leave much space in front of you. Someone who is itching to burn some stress will cut in front of you leaving no space and then hit the breaks.

 

In my experience that's a fallacy. If there is literally ANY space in front of you, that person is going to come in. If you leave more space in front, it gives you the ability to slow more gradually so the person behind you (who is doing exactly what you suggest: following you super closely so no one will "cut them off") doesn't rear end you. Trying to follow closely to keep people out simply doesn't work, but it DOES make it really easy for you to hit the guy in front of you when someone cuts him off.

[David13]

That's the idea.

I have found that a lot of people will imitate the following distance that I use with the car in front of me.

So, if I'm following about 4 car spaces back, they will do the same with me, 4 spaces behind me. They get the idea that I don't want to hit the car in front of me, and they don't want to hit me.

Not all of them, but some of them.

dc

[EddyQ]

In my experience that's a fallacy. If there is literally ANY space in front of you, that person is going to come in. If you leave more space in front, it gives you the ability to slow more gradually so the person behind you (who is doing exactly what you suggest: following you super closely so no one will "cut them off") doesn't rear end you. Trying to follow closely to keep people out simply doesn't work, but it DOES make it really easy for you to hit the guy in front of you when someone cuts him off.

 

Sorry, I may not have been too clear. I am not suggesting riding so close that even a very aggressing driver won't cut in. You are right, a very aggressive diver will come in regardless. However, I am suggesting not to leave an excessive space. If you have an excessive space, not only are you much more likely to get cut off, you can't gauge speed as well and the driver behind is more likely to ride closer because they are itching to pass you.

 

Basically, there is the right space for the situation and traffic speed. I don't think there should be a general rule of X car lengths for Y speed. IMO, 4 car lengths sounds a bit close for speeds excess of 50mph and way too close when traffic is light. But normal heavy traffic volume seldom exceeds 50mph and more likely 20-40mph, where 4 car lengths sounds like it could be a bit too much. It depends on the situation.

 

I am not sure of your experience when driving in traffic. But I can honestly say I have driven in a LOT of heavy commuter traffic for all of my driving life. I've gotten into more trouble with large gaps than with tight gaps. There is no fallacy here.

[szurszewski]

In my experience that's a fallacy. If there is literally ANY space in front of you, that person is going to come in. If you leave more space in front, it gives you the ability to slow more gradually so the person behind you (who is doing exactly what you suggest: following you super closely so no one will "cut them off") doesn't rear end you. Trying to follow closely to keep people out simply doesn't work, but it DOES make it really easy for you to hit the guy in front of you when someone cuts him off.

 

Sorry, I may not have been too clear. I am not suggesting riding so close that even a very aggressing driver won't cut in. You are right, a very aggressive diver will come in regardless. However, I am suggesting not to leave an excessive space. If you have an excessive space, not only are you much more likely to get cut off, you can't gauge speed as well and the driver behind is more likely to ride closer because they are itching to pass you.

 

Basically, there is the right space for the situation and traffic speed. I don't think there should be a general rule of X car lengths for Y speed. IMO, 4 car lengths sounds a bit close for speeds excess of 50mph and way too close when traffic is light. But normal heavy traffic volume seldom exceeds 50mph and more likely 20-40mph, where 4 car lengths sounds like it could be a bit too much. It depends on the situation.

 

I am not sure of your experience when driving in traffic. But I can honestly say I have driven in a LOT of heavy commuter traffic for all of my driving life. I've gotten into more trouble with large gaps than with tight gaps. There is no fallacy here.

 

My apologies in advance - this is one of those subjects upon which I tend to be long winded - read on at your own peril

 

 

I can agree that an excessive space is too much, though in part that's maybe because I spent a few years as an English teacher and am a pretty literal and semantic person; I can also agree that there is the right space for given conditions and speed. I have a hard time though visualizing what spacing is "too much" in traffic. The cool thing about following distance is that you actually get to go the same speed as the car in front of you, which is literally as fast as you can ever go in traffic (because even if you hit them, one that contact is made you're still not going faster than they are) - you just do it further away.

 

If you were constantly decreasing speed in heavy traffic, I can agree that people would keep tailgating and then passing you and filling that space ahead of you. On the other hand, if you keep a constant distance, even if other traffic thinks it's excessive and decides to move into it, what I've noticed is that those people don't really want to be just in front of you, they want to be in front of everyone, so instead of staying in that space in front of you they will instead borrow it for a little while and then move on to take up someone else's following distance.

 

One of the primary reasons traffic congestion occurs is a lack of following distance. Cars are so close that when someone ahead slows a little, or a new vehicle moves into the flow necessitating creation of additional space, the first car slows down and there is a delay for reaction time before the next car slows down, which usually means they have to slow down a bit more than the first, and if they were already "close" to begin with they may have to slow down substantially more than the first car. This produces a wave going back where the decrease in speed is greater for each subsequent car - when it becomes great enough, someone has to stop, and there we are in stop and go traffic.

 

If everyone increases following distance, then when the first car in our example above slows down for whatever reason, the second car can still have that reaction time delay without becoming so close that they feel the need to slow down even more than the first car - they decrease their following distance a bit, but they can also then gradually rebuild it, as can all the other cars behind them. Obviously, you can't get everyone to say, ok, starting tomorrow we all increase following distance (though I've been doing my best to make that happen for several years now - seriously), but as a great post above says, you can set a good example, and when you do that at least SOME people will emulate your behavior. If lots of us do it, then that SOME becomes a really significant group of people. Even if no one follows your example, you'll have to brake less often and slow less to adjust to changing traffic flows.

 

That leaves us with the sometimes tricky bit of how much following distance is the right amount for whatever the given conditions. In current best practices in traffic safety, we don't actually measure distance in, well, distance - we measure it in time. (It works better for a bunch of reasons, but my favorite is that a lot of us, like me, are bad at judging distance, but we're reasonably good at counting to, like, four or six.) My go-to following distance for most conditions is four seconds (someone passes a non-moving something, and I should be able to count four seconds before I reach whatever it was); if I'm at high speeds, like freeway and above, or if road conditions are impaired (rain, snow, darkness, fog, etc.) I try to take it up to six seconds. If I'm going really slowly - definitely less than thirty, and preferably less than twenty - I can let it get down to two...but that's mostly because I'm lazy and impatient and it takes slightly more work to keep it at four.

 

(slight side-note: at 40 mph, four car lengths {sixty feet} is only one second of following distance; standard for human reaction time is usually about .75 seconds, which means that if the car in front of you slams on the brakes or swerves to avoid a blocking hazard, the average person will be ten feet from where the car ahead started braking or turning before your body is doing ANYTHING to cause a change in your speed or direction...assuming you were paying really close attention when the car ahead did whatever it did.)

 

Here's my thought on space, especially following distance because that's the space over which we have the greatest control: more is better. Space lets you fix mistakes made by others as well as mistakes we might make. I have a slide in a presentation that lists the top crash-causing errors for teen drivers in the US; one of the things on the list is "failure to maintain space." That hilarious, right? Because, I mean, that's actually the definition of a crash. It still makes sense though.

 

I'm sure you have more miles and hours in heavy commuter traffic than I do (I've been lucky enough to arrange my life so that I've never had a traditional commute - or at least not a long one; I did once for about five months have to drive about five miles across a relatively small Colorado town to work - but not at normal people hours), and I'm not trying to say you're wrong or crazy or whatever. I'm just saying, think about it and maybe actually try it - for a good period, like a week or whatever - and see what happens. Maybe it will work for you and maybe it won't.

 

josh

 

 

[EddyQ]

josh,

 

Believe me, I love a good distance ahead of me. As you say, it gives you more time to respond, better visability ahead of you and overall more comfortable ride. I avoid heavy traffic as much as I can for those reasons. And when I do find uncongested roads, the distance is opened to thousands of feet . . .

 

I cannot argue with your math relative to 40mph, four car lengths, reaction time. You are right. If everyone kept more distance it would help. But, that isn't going to ever happen. Keeping alert and having stopping alternatives open are your best defence against these cases.

 

I am not convinced stop and start traffic is primarily caused by drivers driving too close. But perhaps those panic stops would be softer if everyone was alert, didn't panic and had greater distances. Route 128 (I95) around Boston during commuter hours has stop and start as well as waves of congestion and many panic stops. I've been unfortunate to need to drive it for years (not no more though ). It is a complex unstable system. While commuting this road over the years, I have had two cars screech and spin out behind me. Both cases, the driver was well behind me. My only thoughts are that these drivers were not paying attention, which I find is a trend with drivers who leave a large distances. I've never had this problem with commuters that drive with a reasonable, but not too tight, distance during countless panic stop situations. In fact, I have never been rear ended and never hit anyone (ok, now I've doomed myself . . .)

 

Try this. When in heavy volume of traffic, keep a precise constant safe distance. Obviously this distance would need adjusting if the general speed changes significantly and safe is subjective. It is harder to do than you may think. It keeps you very alert. If your lane has drivers who vary speed greatly, you notice it and may be able to get yourself into a different lane before trouble occurs. So far it works for me....

 

I donno, maybe driving in other parts of the county things are different. . . .

[szurszewski]

 

Try this. When in heavy volume of traffic, keep a precise constant safe distance. Obviously this distance would need adjusting if the general speed changes significantly and safe is subjective. It is harder to do than you may think. It keeps you very alert. If your lane has drivers who vary speed greatly, you notice it and may be able to get yourself into a different lane before trouble occurs. So far it works for me....

 

I donno, maybe driving in other parts of the county things are different. . . .

 

I think we're advocating for the same thing here, as I already do, and teach, what you're suggesting. Well, sort of - I could quibble about the words precise and constant. BUT where I think we differ is the method used for measuring the space (I use time - easier to accurately judge and automatically adjusts physical distance to speed of traffic), and maybe the amount of space.

 

Sorry for the delayed reply - saw your post right away and wanted to give it some thought before I replied...and then I had a sick five year old the first weekend of kindergarten followed by a terminally ill water heater (with very outdated wiring...).

 

 

[Bud]

To expand the topic a bit.

 

How about following distance when riding with other motorcyclists?

 

 

[szurszewski]

To expand the topic a bit.

 

How about following distance when riding with other motorcyclists?

 

 

That's outside my professional purview, but I try to keep a lot of space. I'm not very smart which means I sometimes do weird things with my bike, or I find something pretty to look at off the side of the road. Bikes can stop and/or changes positions so quickly, I really don't like to be close to other riders lest I run into them or do something that makes them run into me.

 

Which is to say, I still try to keep four seconds. I rarely ride with others though, and almost never in groups. When I do and someone is two or fewer seconds behind me, I find it very distracting and start inadvertently paying more attention to them and less to what's ahead. Fortunately, I also ride slower than most folks, so I usually just drift to the sweep spot.

[Selden]

I took a driving skills refresher course 2 weeks ago, and became acquainted with a concept I hadn't heard before: 3 seconds. Whatever speed you are travelling, find a landmark ahead, start counting when the vehicle in front of you passes that object. Ideally, you should pass the same landmark after a 3 second count. Much easier to comprehend (and put into practice) than 1 car length for each 10 mph.

 

The 3-second Following Distance Rule

[szurszewski]

I took a driving skills refresher course 2 weeks ago, and became acquainted with a concept I hadn't heard before: 3 seconds. Whatever speed you are travelling, find a landmark ahead, start counting when the vehicle in front of you passes that object. Ideally, you should pass the same landmark after a 3 second count. Much easier to comprehend (and put into practice) than 1 car length for each 10 mph.

 

The 3-second Following Distance Rule

 

Selden - that's the current best practices method for following distance as explained in the super lengthy post I made a few above this one (which you and other wise folk probably skipped or skimmed) - though I would argue that the four seconds we teach is one second better (sort of like an amp that goes to 11).

[Warhorse]

I'm a bit surprised that the greatest potential for disaster is the driver of the 4 wheeled clown box. I watch for CELL PHONES. I look for eyes doing that subtle (but so easy to detect) glance down while they are texting while driving. The size of some of these slabs is disturbing. A Samsung Galaxy literally blocks the left side view of the driver, as if they'd be looking anyway.

 

Velocity and distances are rendered mostly mute when a cell phone is being employed, just assume someone on a phone is going to do the stupid thing. I live in area where traffic isn't too bad, but once or twice a week someone blazes a light and KILLS a rider. LE stats are that 80% of these drones are on their phones. That's usually captured by the traffic cam (not a fan, but it has it's uses).

 

Hands free devices DO NOT HELP. The mind is easily distracted. Multi tasking ISN'T, all it really means is that all that tasks being "multied" are performed at a much degraded level. There is no 250% of a pie. I HAVE seen a few Harley riders, not the new lawyer/banker riders, but the old school ones, pound a boot off the silver (camry, corolla, ford chevy or dodge SUV). No, the offending driver doesn't react flinchingly into the rider, the go the other way, away from the rider. Other than hitting someone else on their right side, I don't really care what they hit.

 

This post has some sharp points, may offend some. If you're a MC rider, you've got no business using a cell phone while driving, it's irresponsible. But being responsible is being redefined these days.

 

The human reaction time from brain command to fine motor skill response is 460 milliseconds, that's a lot of rear end closure rate when stuff goes south.