Road Worrier

Median debate takes a turn

Staff WriterMay 24, 2011 

After some legislators were stymied in their push to redesign road projects they didn't like, there were jokes about how the state should prosecute the pols for engineering without a license.

Now a North Raleigh man who made news when he faced that rap - and beat it - is ready to lend his amateur expertise to a new cause.

David N. Cox offers ammunition for politicians and residents who oppose a particular trend in traffic engineering: the construction of raised medians in place of center turn lanes on four-lane roads.

The medians restrict left turns, and merchants say they're bad for business. The Department of Transportation and professional traffic engineers maintain that studies prove the medians reduce congestion and cut crashes on busy roads.

But Cox and other citizen-engineers are stepping up with contrary interpretations of these same studies.

Reading through a 2005 N.C. State University analysis that endorsed medians, they have plucked out some numbers to back their argument for center, two-way turn lanes.

"The assumption that medians are safer than center turn lanes doesn't hold up when examined more closely," Cox said in email to the Road Worrier. "Indeed, the evidence that we found demonstrates that the opposite is more often the case."

Joe Hummer, an NCSU engineering professor who conducted the 2005 study, stands by his conclusions.

"They are in concert with worldwide professional opinion," Hummer said by email from Nanjing, China, where he was giving lectures. "Every study done with a decent methodology on this subject that I have seen comes to the same conclusion, that medians save collisions."

A fight over signals

Rush Limbaugh and others ridiculed DOT a few months ago after the department's chief traffic engineer accused Cox of practicing engineering without having a professional license, as required by law.

Cox had circulated a sophisticated-looking critique of an engineering study that had undercut his push for more stop lights on a Falls of Neuse Road widening project. After he refused to identify the authors, a professional licensing board dropped DOT's charge against him.

Before losing that fight with DOT over traffic signals, Cox and some of his neighbors had fought unsuccessfully in 2008 to block plans for raised medians on Falls of Neuse Road. They conducted their own examination of other Raleigh roads, and they cited parts of the NCSU study to back their claim.

Cox revived his median argument this month, after the Senate shelved a bill to veto medians planned on a few North Carolina roads where merchants complained.

He brought up Hummer's NCSU study again - and so did Clifton Bryan of Blowing Rock, who works for a hotel that would be affected by a planned median on U.S. 321.

"With the results of this study brought to bear ... legislators might give communities a choice," Bryan said by email. "Perhaps a second effort could be successful."

What an engineer says

Jim Dunlop, a DOT congestion management engineer, said studies show medians are safer than turn lanes - except on four-lane roads with few driveways and very light traffic. He said Cox and other critics bolstered their arguments with skewed interpretations of the research.

"They pulled out snippets from a report that said raised medians were far superior," Dunlop said.

"Ultimately, they're concerned about their community, and they want the safest possible roads. However, in my opinion, they have misinterpreted a number of reports."

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