I was driving east on Indian School Road yesterday evening when things suddenly slowed down a bit west of 16th Street. It was about 5:45 p.m., so a slowdown did not seem unusual. If you've ever driven along Indian School at that time of day, you know it can be a pain, even when traffic is moving along.

I assumed it was just normal rush-hour slowness until I saw people ahead of me merging.

There was a wreck. On that street at that time of day, a wreck usually means a big time backup. Not this time.

Traffic was merging from both the right and the left lanes into the middle, and it was doing so smoothly. Middle. Right. Middle. Left. Middle. Right. You get the idea.

There wasn't an officer directing traffic, but cars were moving as if there were. Everybody was polite, each waiting his turn and letting the next driver go. It was like it had been choreographed. I never even came to a complete stop.

I've never seen traffic move through a wreck scene so smoothly, especially on Indian School Road smack in the middle of evening rush hour.

People in this city are not known for their merging abilities despite the fact that the most common street sign in the Valley seems to be "Lane ends. Merge left."

In fact, people here seem to do some pretty stupid things once they get behind the wheel. It's like they forgot everything they learned in driver's ed. Take those pretty red signs with the letters S-T-O-P in bright, reflective white. Stop signs mean stop. It's not a suggestion.

And don't even get me started on how Phoenix drivers react to rain. It's like water is an invitation to speed. A tiny bit of extra caution would be nice. But no, hydroplaning must be fun.

I've talked about Valley drivers before, making the sweeping generalization that expensive cars are usually piloted by bad drivers.

And with all the construction going on pretty much everywhere, things are even worse. People forget that if they're going through an intersection, they need to make sure there's plenty of room on the other side so they don't get stuck in the middle when the light changes.

That seems to be a particular challenge for drivers heading west on Camelback Road at Seventh Avenue. It's not like the light-rail street surgery along Camelback is new. It's been going on for months. At least they've stopped moving the crosswalks for the moment. For awhile there, it seemed like they were moving up or back every day. It was hard to know where to stop.

Back to the uncharacteristically good driving I witnessed yesterday.

Once I was through the scene -- it took only a few more minutes than usual -- traffic widened back out to go under the S.R. 51. On the other side, it narrowed back down to two lanes because of construction. (Is there any street in this city that's not under construction?)

I found myself side by side with the woman who had let me in back at the wreck scene. Turnabout's fair play, so, of course, I let her merge on in.

You've heard the phrase, "Courtesy is contagious." I guess it's true. Sometimes.