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.