A wise man once shared with me, “Luck is the residue of design.” By the looks of the Arizona Department of Transportation’s first design, good luck everyone — we’re going to need it.

Just a Second: By Nate Hansen 

A wise man once shared with me, “Luck is the residue of design.” By the looks of the Arizona Department of Transportation’s first design, good luck everyone — we’re going to need it.

Two weeks ago, after speaking with Carl Burkhalter, engineer and project manager for ADOT’s ongoing construction along Hwy. 179, I learned the first roundabout — located at Back O’ Beyond Road — has a radius of 40 feet measuring center to the gutter.

It measures 36 feet from center to the curb, where the roundabout meets the outer edge of a planned truck apron, he added.

Being the skeptic, I drove down to Back O’ Beyond when ADOT workers weren’t present — which could have been anytime.

Since the project is only half apparent, I measured every radius. Sure enough, Burkhalter was correct.

Unfortunately, before I left, I discovered a few things that made me cringe like a pit bull in an Atlanta humane society — or like Barry Bonds at a urinalysis.

Although I received specifics for every radius, I was only given vague measurements for the entryways and exits around the roundabout. Curious, I measured the shortest distance between the two curbs entering the roundabout heading northbound.

One distance was around 27 feet; the other around 21 feet. After speaking with a foreman at the project Friday morning, he confirmed the differences.

Although the U.S. Department of Transportation’s sixth chapter of Roundabout: An Informational Guide reads “typical entry widths for single-lane entrances range from 4.3 to 4.9 meters [14 to 16 feet], it also reads they “should remain constant throughout the roundabout.”

In addition, it reads “values higher or lower than this range may be required for site-specific design vehicle and speed requirements for critical vehicle paths.”

We already know the road widths change, despite USDOT’s recommendation, but what is a site-specific design vehicle? And, what are speed requirements for critical vehicle paths?

Before I answer those questions, let me inform the public USDOT also states “a roundabout  designed to  accommodate design year traffic volumes, typically projected 20 years from the present, can result in substantially wider entries and circulatory roadway than needed in the earlier years of operation.”

In this case, Sedona better plan on halting its growth or reroute larger vehicles through Cottonwood. Hwy. 179 isn’t going to take much more traffic the way these designs are going and construction in the future will surely be the death of the town.

Monday morning, Aug. 6, I called Burkhalter again. He informed the inside diameter, or landscape, was around 55 feet and the entire roundabout’s diameter was “82, 83 feet.”  The distance between centerpiece and road was designed for a truck apron.

Thanks, I said. More clarity.

Unfortunately, the information was as disappointing as the press’ persistence to cover Lindsay Lohan’s addictions.

According to the roundabout guide, the typical design vehicle for the inscribed circle diameter range at Back O’ Beyond, which is described as an “Urban Compact Site Category,”  should be for a “single-unit truck/bus.” 

The informational guide goes on to say “the inscribed circle diameter should be a minimum of 30 meters [100 feet] to accommodate a WB-15 [WB-50] design vehicle,” otherwise known as “semitrailers large” — are common vehicles that enter Sedona.

Remember, the roundabout at Back and Beyond is 80 feet. Oops.

I asked Burkhalter about the discrepancy and he said he’d get back with me. But in the meantime he’d send four computer-graphed diagrams proving a WB-15 [WB-50] vehicle can navigate the Back O’ Beyond roundabout.

Well, I once watched George W. Bush land a jet aboard a Navy aircraft carrier to announce the end of the war — it doesn’t mean it’s going to happen.

Finally, a couple hours later, Burkhalter called back after conversing with the “designer” of the Back O’ Beyond roundabout. To his surprise, roundabout diameters include the outside curb, furthest from the actual circle and truck apron.

Ends up, there are differences between all these circles. Imagine that.

So, in closing, though I stand corrected, I suggest using Page Springs Road. Out of sight, out of mind.

Nate Hansen can be reached for comments at This e-mail address is being protected from spam bots, you need JavaScript enabled to view it Read past “Just a Second” columns at www.redrocknews.com.

Average user rating

   (0 vote)