Hello, it’s me again with your traffic answers

It's time for the Road Warrior shuffle. In today's edition, we'll have answers to a couple of pressing questions about pedestrians, crosswalks, cars and who's got the right-of-way, anyway?

We'll also have the new guy, who's the same as the old guy.

And, if you stick around for the end, we'll have the very best Road Warrior answer in the history of answers.

Ready? Let's go.

J.D. writes in, and I sense some anger.

"I delivered my granddaughter to her high school and received a ticket by the school police for the following," J.D. writes.

Basically, the police officer ticketed J.D. for going through a crosswalk when there was a pedestrian entering the crosswalk on the other side of the street.

"Should I fight this in court or is he correct?" J.D. wonders.

No way I'm answering that one. That's between you, your lawyer and your wallet. But I will give you a tutorial on the law, so you can figure it out for yourself.

Nevada Highway Patrol trooper Loy Hixson says it used to be drivers weren't allowed to go through a crosswalk if a pedestrian was in it. No matter what.

But that was changed a while back. Now, if it's a divided highway - that means any divider, from a 50-foot-wide median to a tiny strip of concrete - and the pedestrian is on the other side of the divider, feel free to drive through the crosswalk.

But the moment those feet hit your side of the street, stop.

It's the same rule, by the way, for emergency vehicles and school buses. You don't have to stop if they're on the other side of a divided highway.

Joseph writes in to complain about what's come to be the Road Warrior's favorite topic: Those newfangled flashing yellow turn lights.

He says pedestrians are in great danger at the intersection of Tropicana Avenue and Grand Canyon Drive in the southwest part of town.

On alert for danger, I drove out that way.

Huh. Looks like any old intersection in the developing part of town. A couple of vacant lots. A strip mall. A car wash.

What's the danger?

Those flashing yellow turn lights, Joseph writes. Those things are going up everywhere, by the way. They're replacing the green circles, but they operate the same way. So Joe's question applies pretty much to any intersection with cars, lights and people.

He's a little wordy, so I'm going to make his point for you: The flashing yellow turn lights make it dangerous to walk across Tropicana in the crosswalk because there could be cars coming.

He's right. Walking across Tropicana is dangerous. There, in fact, could be cars coming.

But it's not the light's fault.

This here's from Dan Kulin, a spokesman for Clark County, which operates the traffic controls in that intersection:

"The flashing yellow works the same as the green ball did that was previously there and exists at hundreds of other intersections. A flashing yellow arrow means a vehicle is allowed to enter the intersection and proceed with caution in making the left turn. As always, drivers must YIELD to oncoming traffic and pedestrians."

In other words, the new light is the same as the old light. And drivers must wait for people in the crosswalks.

Next?

OK, I've put it off too long.

I'm not Joe Hawk. I'm Richard Lake. I used to write this column, then went off and did other things, and now I'm back writing this column again.

Why? Because Heraclitus was right when he said change was the only constant in life.

So. Now. Moving on.

This one came in via the Review-Journal's News Tip line. The tipster writes:

Is there a minimum yellow duration between green and red, with that minimum yellow duration being based on the maximum speed limit of the street it controls? People should have more time to clear the intersection when the speed limit is 50 mph, compared to a limit of 25 mph.

This makes so much sense that I had to read it twice to make sure the sciencey language hadn't tripped me up. The higher the speed limit, the tipster says, the longer the yellow light should last.

Whoa. What a cool idea.

Guess what? It turns out that's exactly what happens locally.

Diana Paul, a spokeswoman for the city of Las Vegas, translated the stuff the city's traffic engineers passed along. And therein comes the Very Best Answer Ever.

Are you ready? Here's how they figure out how long the yellow light should last.

Y = Tr + S/(2(10+32G)

Y is how long the yellow light is going to last (with a minimum of three seconds and a maximum of six).

Tr is a driver's reaction time.

S is the speed.

And G is the grade of the road. In other words, is it uphill or downhill? Because it's harder to stop going downhill.

This stuff comes from the Manual on Uniform Traffic Control Devices, put out by the Institute of Transportation Engineers. It's the national standard.

When you run the formula (don't worry, I'm not going to make you do the math), basically you come up with this: Yellow lights should last about three seconds in 25 mph zones, four seconds in 35 mph zones, and 4.7 seconds in 45 mph zones.

So that's how things are programmed around town. How cool is that?

Now, I'm off to brush up on my algebra.

Send traffic and transportation questions, comments and gripes to roadwarrior@reviewjournal.com. Follow the Road Warrior on Twitter: @RJroadwarrior.