Casual Fridays: Driving like maniacs

[I've been sick the past couple days, so I'm not going to be able to post a new Casual Friday today. But here's an old one that many of our readers probably haven't seen.]

Last week's Casual Friday survey asked readers to describe how they expect other drivers to behave when merging onto the freeway. Now that the survey has been completed, I can let you in on a bit more of the observations that motivated the survey. I live in North Carolina, and I like to visit the big cities on the East coast, especially Washington and New York. This means I've done a lot of driving through Virginia, and I thought I'd noticed a peculiarity about Virginia drivers. In Virginia, it seemed to me, like no place else, the other drivers always expect you to get out of the way when they're merging onto the freeway. Sometimes it seems as if they don't even look to see if anyone's coming before they barge out into traffic.

But perhaps these incidents become exaggerated in my memory, and Virginia drivers aren't any better or worse than they are anywhere else. Now we have a chance to find out: we've again maxed out our survey engine, with 250 responses. I was hoping for a broader geographic distribution of response than we achieved: just 16.4 percent of respondents came from outside of North America. This contrasts to a sampling of 100 readers from our stats page this morning, where around 50 percent of visitors came from outside the U.S.

Possible explanations: people in other countries don't drive as much as Americans, or, since the survey was posted late Friday afternoon in the U.S. -- already late evening in Europe -- our response was skewed to North America (as I write this, at around 2 p.m. Eastern time, over 80 percent of recent visitors come from North America).

Nonetheless, because of the large sample size, we were able to attain significant results. Let's have a look at the numbers! The first question was intended to test the "Virginia hypothesis" -- the idea that certain drivers expect the people on the highway to get out of their way, rather than seeking to modify their own driving behavior to adapt to driving conditions. Here's a summary of the responses:


The largest portion of drivers, whether in North America or in the rest of the world, expect the drivers on the highway to maintain their current speed. While a greater portion of North Americans expect other drivers to change lanes than non-North Americans, this difference wasn't significant. However, significantly more non-North Americans expect others on the highway to slow down for mergers compared to North Americans.

Now, what about when a driver is on the highway and others are merging. How do drivers expect mergers to behave?


Overwhelmingly, freeway drivers expect the people who are merging to slow down in order to merge. (This question also generated my favorite "other" response: "Some essentially random action." 14 respondents offered a pair of responses that perplexed me: they expect people who are merging to slow down, and they also expect people who are already on the freeway to slow down. How does that work? Does everyone eventually end up standing still?)

This is fascinating stuff, but I still haven't found a statistically significant confirmation of the Virginia hypothesis. Next I took a look at population density. There weren't any significant differences between urban and suburban areas, so I combined that data and compared it to rural areas:


Here we have solid evidence suggesting that the behavior I noticed is not confined merely to Virginia: A whopping 58.1 percent of rural drivers say they expect others to change lanes to get out of their way when they are merging onto the freeway, compared to just 26.3 percent of urban and suburban drivers. What I was thinking of as a Virginia effect is really a rural effect. And when I think about my drive from Charlotte to either Washington D.C. or New York, I have to admit that nearly all of the rural sections of that drive are in Virginia. There really isn't any rural section of the drive on Interstate 95 from Washington to New York.

So are there any differences in how rural and urban / suburban drivers expect others to merge? Here are those results:


Here, as with the overall results, most drivers expect the person merging to slow down, and there are no significant differences between rural drivers and urban / suburban drivers. But one "other" comment from a rural may explain this discrepancy: "I don't ever recall having seen this happen." Perhaps rural drivers simply don't expect there to be a case when they can't get out of the way of merging traffic, so they believe that if such a situation ever occured, the merging traffic would just slow down. This would be consistent with my experience driving through rural areas, where most drivers who are merging appear to assume that the drivers on the highway will just get out of their way.

Are these results consistent with your driving experiences? Do you have any other questions about the data, or alternative explanations? Let us know in the comments.

The next Casual Friday study will appear later this afternoon next week.

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You know, for the last two years, since you first posted this, I remember it every time I get (or try to get) on I-40, which is almost every day!

I live just north of Toronto Canada. Over many years of driving, I've learned that if my own safety is my primary concern (which it is), the only sane expectation is that other drivers will behave erratically.

In other words, if I expect a certain behaviour from others, I raise the chances of getting into difficulty.

By Scott Belyea (not verified) on 29 Feb 2008 #permalink

We lived for nine years in an area that was "rural", ten miles away from a town of about 50,000 people. Traffic on the highway was inevitably light; when I was on the highway and people were merging, I would move into the other lane, and other drivers did the same. The reason? It was easy to move into the other lane because there was no traffic. That way, if the other driver behaved erratically, as Scott points out is the best belief, you'd be out of his way.

Speaking as someone who has taken driver's ed and defensive driving courses, I can say that the proper behavior for drivers is to change lanes if possible when another car is entering the freeway. If traffic prevents you from getting over, you should maintain speed. Drivers entering the freeway are required to yield the right of way, but should ideally use the entrance ramp to accelerate up to highway speed. So I wouldn't characterize changing lanes as "getting out of the way" of merging cars, but rather as facilitating safe and smooth traffic flow.

This survey is great. This topic has been bugging me for quite some time. I lived in San Diego for 3 years and, although I didn't have my own car, became used to the highway driving there. Coming from Kansas, California driving seemed horribly fast-paced and erratic. However, once you understand what is going on around you, it is actually very efficient. Cars on the highway roughly maintain their speed and allow enough room for those merging. Those merging are expected to meet the speed of the traffic on the highway and merge without causing much difficulty for those already on the highway. And, that's it.

Moving back to Wichita, Kansas, I was in for a shock. Mergers expect those on the highway to vacate a 300-ft slot to accomodate their 40-mph merge. It is ridiculous. I've had mergers approach highway speeds and be ready to merge in front of me from the onramp, then suddenly slam on their brakes (forcing me to swerve to the left) because they were shocked to see anyone in the right lane; mergers force me to either mash the accelerator or brake because they refuse to alter their speed (which is identical to mine) and they are directly alongside me on an onramp; and mergers come to a complete stop on an onramp because there are other cars in their field of vision. What is incredible is that this behavior usually occurs when there is very light traffic--in theory, making it much easier for someone to merge. The first thing that always comes to mind is, "Oh no, they've been forced to think in two dimensions. What was I expecting of them?"

This is ridiculous, unsafe, and inefficient. Perhaps the yellow Yield sign should be followed with a brief definition of the word.

I have driven in Caracas so I have no fear. In Venezuela you do not hesitate, but assume no one will ever hit you. There are not as many wrecks as you would think. My wife would not ride with me for a week or so whenever I came back from Venezuela.

By Jim Thomerson (not verified) on 29 Feb 2008 #permalink

This explains so much - I learned to drive in California, where it was congested and you did NOT screw up the flow of traffic. And since the vast majority of people drove this way, traffic managed to flow.

Now I live in Colorado; every day that I drive, I curse the inability to merge that surrounds me. The Front Range is urban/suburban, but apparently everybody still thinks it's rural.

My mental chatter isn't quite as nice as Mike's (#5) but I think we're dealing with the same people.

I remember this Casual Friday when it came out; it is one of my favorites!

My driving experiences mirror Mike's, having lived in urban (San Diego, San Francisco area, New York) and relatively rural (New Mexico) areas, with a lot of Interstate driving done back and forth between these areas. I assumed it was a coastal vs. middle america thing, but urban/rural is probably more on the mark. In urban areas, the "merger" is supposed to be polite and yield, while in rural areas the "mergee" is supposed to be polite and accommodate the traffic joining the freeway. Funny thing is that, for the most part, people who learn to drive in one environment have no idea (at least I didn't for the longest time) that different "rules" applied/were learned in the different regions. Having learned to drive in an urban area, initially I thought the middle america drivers were being rude. They probably thought I was.

Here in RI you take your own life into your hands when you merge into highway traffic. There's a prevailing attitude here of "Me first!" that makes it interesting all the time.

I've driven extensively in RI and MA and I'll tell you the key difference between the two states.

If I'm on I-93 in MA going towards or away from Boston there are usually enough gaps in the shoulder lane to merge in.

Once in traffic changing lanes in MA is great. Signal, a hole opens, move in and done! In RI I think people here think "Ooo, look at the pretty flashing light."

I drove cab for eight years, and my experience boiled down to one simple rule: I yield to everyone and everything.

I also expect nobody else to follow any rules. I have twice turned onto a freeway onramp only to encounter wrong-way traffic, but since I was ready for it, my cab never got touched. Both times I surprised the other driver by going off the pavement, onto the slope to get around him, then dropping back onto the pavement to make the freeway.

I live in Florida, so I don't expect anyone on the road not to make their best effort to kill me.

I take any steps necessary, to avoid being run over by our legally blind septuagenarian drivers. Ideally changing lanes to allow folks to merge. Failing that, I'll speed up because folks entering a 70 mph highway, where everyone is doing 80, tend to be doing about 40 and I'd rather be in front of them(depending on the amount of traffic and how many folk are merging). I try to avoid slowing down, because I don't trust the person behind me to take their attention off their cellphone or big mac.

If there is even a little traffic merging onto a rural road, about 1/3 of the folks stop, 1/3 merge over the solid white line and drive around stopped cars, and 32% end up in the breakdown lane. I tend to scream profanity while waiting for the first third to get out of my way, and pray to a god I don't normally believe in that the other 65% don't cause an accident further delaying my commute.

The idea that people should move out of the right lane every time a car is entering the freeway sounds hazardous to me, but that's probably because I live in urban Southern California. We have onramps every mile or so, traffic pretty much 24 hours a day, and the cars in the slow (right) lane are either those entering or exiting the freeway, or are traveling more slowly than the general flow of traffic for some reason (usually trucks), so that a lane change could impede the normal flow of traffic. Merging does involve a bit of interaction: vehicles in the slow lane are expected to speed up or slow down to give the merger space to enter the freeway, while the merger is expected to get up close to freeway speed, slowing down or speeding up to fit into the available space. (Basically what Mike said above.) It sounds complicated, but it works well in practice. Occasionally I've seen someone who appears too timid to merge smoothly (visitor from Kansas?), which not only is dangerous for that driver, but backs up traffic both on the ramp behind him and in the right lane, as cars have to slow down considerably to let the driver in. I can't imagine driving somewhere where that kind of behavior is routine.

I live in New Hampshire, which (as Tara reports is true of the Colorado Front Range) many people assume is rural but in fact is heavily urban/suburban. It regularly annoys me that people ahead of me on freeway on-ramps make no attempt to accelerate up to the posted speed limit before merging, even when ramp geometry allows it. There are three on-ramps on which I routinely encounter this problem: 293 S from Brown Ave. in Manchester, 101 E from 125 in Epping, and 16 S from Indian Brook Dr. in Dover (but I have encountered similar difficulties on other ramps). It's not quite as bad as Kansas: full stops occur only when traffic is so heavy that it's difficult to merge in anyway. Still, it's not unusual that I overtake one of these slow mergers once I myself have merged.

In Maine and Vermont (most of which are truly rural), you are expected to try to get out of the way of mergers, but they will adjust if they see that you can't (because somebody is passing you at the same time).

I grew up in Miami, which is a no-holds-barred driving environment thanks to the combined influences of New York City and Latin America. You learn to watch out for trucks changing lanes--they'll squeeze into a gap that rural drivers would think twice about putting a subcompact through. Of course, this may be one reason I don't "get" the unwillingness of NH drivers to get up to speed on on-ramps.

There seem to be subtle differences in detail from one area to another regarding what is expected. Maybe it's that I have done more driving in the Bay Area than LA, for example, but I have learned what to expect on Bay Area freeways, while LA still gives me trouble. Similarly, I am accustomed to Boston-style crazy driving due to traveling through Massachusetts several times a year, but I never learned to deal with NYC traffic loonies even in the days when I was making several trips through that region.

By Eric Lund (not verified) on 29 Feb 2008 #permalink

I can't believe people expect "rules" on the road. It's a case by case situation because there's no way in hell everyone will follow the same rules. Sometimes the merger needs to speed up to get on the freakin' highway. Sometimes, if I'm in the right lane and someone's trying to merge, I change lanes if it makes sense. Sometimes I slow down. Sometimes I speed up if I'm going too fast to slow down or there's too much traffic to change lanes and the person trying to merge onto the highway is going 5 mph(!), I speed up and get out of the way and let grandma get on when she can. No way am I slowwing down to 5 mph to let her over. It depends totally on what the other people are doing. I do expect the people on the freeway to try to do something to let me on when merging onto the freeway, but I LOOK to see what they're actually going to do. And, if they want to slow down to let me on, I always try to go at a reasonable speed to get on so they don't have to slow down so much. I don't know why so many people can't see that you have to speed up to merge on the freeway.

I see the problem that the situation in the USA is not comparable in other countries, e.g. in Germany.
If I am the merger, I expect that the driver should
- maintain speed if far away
- hold high speed or accelerate if near enough so that he
passes me and I can merge behind him
- slow down if it is clear that I will be before him,
especially if I run out of the accleration lane.

I will never expect him to cross lanes while many people does exactly this out of laziness or politeness in low traffic situations (so it is not uncommon). The reasons are obvious here:

- The right side is always reserved for trucks, vans and other low speed stuff. As they may drive 50 mph, the normal speed is something about 55 mph (its still under the allowed error limit). If no slow traffic is there, the speed will jump up to 60 mph at minimum (without speed limits) to an average of 80 mph. You are obliged to drive right if you are not overtaking someone.

- The left side (for two lanes) is for the higher speed traffic. If we have three lanes, the leftmost side is used only for overtaking and the occasional 155 mph driver (I am not joking). On this side we have speeds from 80-100 mph; because the traffic is mostly cramped, the fast driving drivers are slowing down, but will accerelate if the left lane, or even better, the right lane is free.

- Together with the fact that the traffic is unfortunately mostly cramped, it may be impossible to change lanes safely
because the dust speck on your mirror may be an car on your left side one second later.

So it is AN EXTREMELY STUPID IDEA here to trust that oncoming traffic will change lanes. It is also a stupid idea to expect "rules"; the situation slow down, maintain and accelerate depends entirely on situation.

This cultural differences may skew your results.

I grew up in Chicago and just recently moved to rural South Carolina. In Chicago, people would never get out of the way and I assumed this is how it was everywhere. When I moved down here I immediately noticed that people consistently tend to move out of the way when others are merging (even trucks and other slower-moving vehicles). I sincerely thought that this was just another form of Southern Hospitality. This blog entry is very interesting and the results of your study seem to make sense.

I don't know if it's still like this, but the first time I drove on a major freeway was in Dallas (circa 1984) - the on ramps had traffic signals! We were sitting at a red light and then expected to accelerate from a full stop in order to enter the freeway! Needless to say, I was petrified, but survived.

When I first started reading this I thought it might be about another hotly debated traffic flow concept: the "zipper merge". What do you do when two lanes of traffic merge down to one, like for construction? Do you wait until the last minute and merge the two lanes like teeth of a zipper, or do you move over as soon as you can? Apparently there are major regional differences in this, and people can provide powerfully persuasive arguments for what they learned, yet people from each region think the others are idiots (especially if they are brought together in one merge opportunity!)

When I learned to drive in France, I was told that the expected behavior for the people merging was to adapt to the ongoing traffic, and for the people already on the highway to maintain their speed. It is written in the rules of the road, actually. I also learned not to expect people to behave as they should, obviously. But seeing that only 50% of the respondents expect the drivers on the highway to maintain their speed is rather shocking to me...

Here in Vermont there are signs on the interstate that say "Thru traffic keep left" around the on and off ramps. So if you're not exiting the highway, get in the left lane and out of the way. But we are definitely more rural.

I've also noticed the phenomenon where activating your turn signal on the highway causes folks in the other lane to make room for you. More people should try it, it might just work elsewhere too.