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Driving on ‘wrong’ side of the road in Henderson

The first time I drove through Nevada’s first diverging diamond interchange, I hardly knew I was in it.

When you look at animations (see below), diagrams and illustrations of the diverging diamond in action, it looks convoluted, confusing, maybe even dangerous.

But fear not.

Although it might be painful for some to admit that French traffic engineers came up with this clever interchange innovation, it’s becoming a popular solution to traffic snags across the United States. Since the last time I wrote about diverging diamonds, when Henderson first announced plans to design and build one in April, 10 more have opened across the nation.

The newest one that opens Sunday addresses a particularly troubling choke point.

Southern Nevada’s first diverging diamond is at the Horizon Drive interchange of U.S. Highway 95.

At that location, the freeway runs parallel to Horizon Ridge Parkway, which lies about 200 feet to the west. Horizon Ridge and Horizon Drive serve as the freeway access to thousands of residents and businesses in a narrow corridor.

There’s a traffic signal at Horizon Ridge and Horizon Drive and another pair on the ends of the freeway overpass.

During rush hours, southbound motorists on Horizon Ridge must turn left crossing traffic, go through the first traffic interchange and then cross traffic with another left turn to head north on U.S. 95.

With a diverging diamond interchange, the second left turn across traffic is eliminated. It will also ease traffic for exiting southbound U.S. 95 traffic heading east on Horizon Drive. Here’s how:

The diverging diamond temporarily moves traffic from the right side of the road to the left.

That means northbound freeway traffic will make an easy left turn without crossing traffic and exiting freeway traffic will make an easy left turn into the flow of Horizon Drive without a signal.

Easy right? No? OK, you’ll have to try it to see how easy it is.

A few months ago, I tried Nevada’s first diverging diamond at the Moana Lane exit of Interstate 580 in Reno.

Maybe it was because the Reno diamond is under the bridge instead of on top of it, making it darker and harder to see, or maybe the concrete barriers that separate the left lanes from the right were taller than normal, but I zipped right through the interchange without even realizing I was in it.

The Federal Highway Administration found that there was a 38 percent decrease in travel time through diverging diamond intersections and an 80 percent decrease in the number of vehicle stops with them. The intersection can handle 650 left turns an hour, about twice the number of a conventional interchange. A Missouri study also found that it cut accidents by 46 percent.

One group of road users that might not like them as much are bicyclists, who will now have to pass through extra intersections to pass straight over the overpass. But Henderson officials note that it will have bicycle paths and will be the first place south of Auto Show Drive that cyclists and pedestrians can cross the freeway.

To fearful motorists, I say try it, you’ll like it. Who knows, maybe the public will demand more of them.


Warrior reader Ann wants some clarity on who has to stop when a school bus activates its flashing red lights on a street where there’s a barrier running along the center of the street:

“I just want to confirm that regardless of what side of the street a school bus in on, don’t all drivers have to stop? While driving west on Charleston Boulevard, a school bus driving east stopped to offload children. Cars driving west kept going. I stopped. The man behind me moved into the left turn lane and began his turn — just as the kids started to run across the street. He had to stop in the middle of his turn. Finally, everyone going west stopped. Yes, there was a concrete divider in the middle of the road, but I thought the divider only mattered when pedestrians were crossing.”

It might seem a little counterintuitive, Ann, but those traveling in the opposite direction of a school bus are free to continue if there’s a barrier separating the lanes of traffic.

“When there is a physical barrier dividing the road, such as concrete or landscaping, drivers traveling the opposite direction of the bus may proceed while it is unloading students,” said Nicole Santero, a spokeswoman for the Clark County School District. “On these types of roads, drivers are required to stop only if they are traveling in the same direction as the school bus.”


That crush of convention traffic last week is gone, but there’s still one relatively large event today through Tuesday at the Mandalay Bay Convention Center as 10,000 attend Redken Laboratories’ international symposium.

Traffic might be heavier than normal along Tropicana Avenue and Paradise Road on Friday morning when the Las Vegas Metro Chamber of Commerce hosts Preview 2015, the organization’s largest networking and educational event, at the Thomas & Mack Center.


If you enjoy reading the Road Warrior column — and honestly, who doesn’t? — you won’t find it here in Sunday’s Review-Journal next week.

The Road Warrior is taking a road trip to Monday’s edition starting next week.

Same coverage about getting around Southern Nevada on everything that moves, but on a different day.

Questions and comments should be sent to roadwarrior@reviewjournal.com. Please include your phone number. Follow @RJroadwarrior on Twitter.

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