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Napa County's traffic growth is more than anecdotal
Traffic Tales

Napa County's traffic growth is more than anecdotal

From the Series: Traffic Tales of Napa County series

(Traffic Tales is an occasional feature looking at traffic congestion issues in Napa County. Readers are encouraged to contact reporter Barry Eberling with suggested stories.)

Napa County’s traffic saga can be seen through two lenses – people’s experience and the cold, hard numbers of traffic counts done over the decades.

They both tell stories of growth. But the numbers show that some sections of Napa Valley’s workhorse roads – Highway 29 and Silverado Trail – have seen far more growth than others.

Doug White, 48, grew up in St. Helena and lives in Napa. He recalled when he could drive between St. Helena and Napa in 20 minutes in the 1980s, rather than 45 minutes or more at times today.

Meanwhile, Silverado Trail has grown from a traffic escape route for locals avoiding Highway 29 to a crowded roadway, he said.

“I love the way Napa is changing, I think it’s great,” White said. “But there are days that are frustrating.”

David Jennings, 65, grew up in Napa. He remembers when the local freeway stretch of four-lane Highway 29 had two lanes crossed by local streets. Traffic just grows thicker and thicker, he said.

“I try to avoid driving as much as possible in this town,” he said.

Traffic congestion is a ubiquitous topic in Napa County, kind of like the weather, a shared experience that can always be broached when the conversation starts to sputter.

But take warning—congestion conversations come with a certain amount of outrage. After all, this isn’t Los Angeles or the heart of the Bay Area. This is rural Napa County, the place with the agriculture preserve and the relaxing, wine country lifestyle.

The state Department of Transportation for decades has kept Highway 29 traffic counts. Numbers have grown dramatically over the past quarter-century, though not at all locations over the shorter timeframe of the past decade.

Highway 29 at American Canyon Road in 1993 had an average of 31,000 vehicles daily. That exploded to 50,000 in 2005, fell to 41,500 in 2010, then rebounded to 48,500 in 2015.

Trends there seem influenced both by population growth and by the economy, with a dip during the Great Recession. The bottom line is that anyone traveling through American Canyon during evening rush-hour might end up with a frustrating, bumper-to-bumper experience.

The highway at First Street in the city of Napa, on the other hand, is the county’s most consistent growth hot spot. The daily average of 46,000 vehicles in 1993 became 58,000 in 2005, 59,000 in 2010 and 68,000 in 2015.

Despite the unrelenting growth, this stretch of Highway 29 has avoided becoming a gridlock ground zero. That’s because it’s a four-lane freeway with interchanges instead of stop signals. Traffic alone doesn’t equal congestion.

Beyond Yountville comes the heart of Napa Valley wine country. This is a particularly tough area for traffic solutions, given that it is served by two-lane Highway 29 to the west and two-lane Silverado Trail to the east.

Local leaders fear creating four-lane versions would annihilate the agricultural ambiance of the ag preserve. Nor do they suggest plowing up vineyards to make room for a reliever route.

“I do not foresee this Board or another board creating another Silverado Trail,” Board of Supervisors Chairwoman Belia Ramos said at a spring county brainstorming session.

The good news is that traffic growth in recent years has slowed after a big burst. The bad news is a 1990 traffic study said the area was congested even then, having seen 20 percent to 40 percent traffic growth over a decade. That makes subsequent traffic growth congestion-plus.

Highway 29 at Oakville had 15,100 vehicles daily in 1993. This grew to 25,500 in 2005, then leveled out at 24,100 in 2010 and 24,600 in 2015.

The highway then passes through the historic downtown of St. Helena, with its stores in buildings dating back as far as the late 1800s. Traffic grew from 18,000 in 1993 to 18,300 in 2005 to 19,300 in 2015.

To put the growth in even sharper relief, the traffic count for this St. Helena location in 1977 was 13,337.

Finally, the Upvalley stretch of Highway 29 between St. Helena and Calistoga has a similar traffic story. Average daily traffic at Larkmead Lane grew from 10,500 in 1993 to 13,400 in 2005 to 14,400 in 2015.

But what about the valley’s other main road, Silverado Trail? White sees the change there over the past few decades.

“There’s a lot more traffic,” he said. “There’s a lot more tourists driving under the speed limit looking for turns, not knowing where they’re going.”

Quantifying this growth is difficult. The stretch of Silverado Trail in the northern Napa Valley isn’t a state highway and is not subject to Caltrans traffic counts. County traffic counts are spotty.

Still, the county in 2003 found that 5,017 vehicles daily used Silverado Trail north of Deer Park Road. A 2014 environmental study done for the Melka winery put the number at 6,401, more than a 20 percent increase.

Meanwhile, Napa County’s traffic congestion is barely a blip in the Metropolitan Transportation Commission’s Vital Signs congestion report. This report looks at the percent of miles driven in traffic for the nine Bay Area counties.

The share of miles driven in congestion in Napa County is a mere .2 percent, compared to 5.7 percent for the Bay Area, the MTC report said.

“In the more northerly counties of Sonoma, Napa and Solano, drivers spend very little time in congested conditions,” the report said. “These counties have seen little-to-no growth in congestion over the past decade.”

But Vital Signs gives a distorted picture because it looks only at freeways. In Napa County, it focuses only on the brief Highway 29 freeway stretch in the city of Napa, one of the few locations that’s congestion-free.

That raises the question of whether Napa County can haul in the big bucks for big projects. Does MTC, an agency with a huge influence on regional transportation spending, understand Napa?

Congestion management means something different in San Francisco than it does in Napa, said Supervisor Alfredo Pedroza, the county’s MTC representative. He advocates the perspective of the smaller counties, he added.

Pedroza thinks Napa County’s traffic problems are known in the greater Bay Area world.

“That’s the unique part,” he said. “While we are a smaller county, we have a lot of neighboring county residents and Bay Area residents who visit Napa.”

Pedroza thinks Napa County can make a traffic difference with smaller as well as larger projects, such as by synchronizing Highway 29 traffic signals to allow better traffic flow.

Some residents blame Napa County’s traffic congestion on wine country tourism and that’s undeniably a factor. Anyone stuck in a long Highway 29 backup on a Saturday morning trying to enter St. Helena would be hard-pressed to say otherwise.

This issue too can be viewed both anecdotally and with numbers. Consultants Fehr & Peers tried to sort out who’s clogging up the roads – tourists, locals or commuters – in a 2014 study for the Napa Valley Transportation Authority.

Twenty-one percent of daily trips into the county are visitor trips, the study calculated.

A look at 434 local wineries in October 2014 concluded they generated 52,245 trips on Thursday, 62,217 trips on Friday and 54,713 trips on Saturday. Fehr & Peers arrived at this number not by counting vehicles at the driveways of every local winery, but by using a formula.

In addition, Napa County over three decades has seen more traffic simply because the county has more people. The 1990 population of 111,000 is now more than 136,000.

Fifty-five percent of the drivers on local roads started and ended their trips within Napa County, the Fehrs & Peer study concluded. In other words, these trips are from Napa County residents on the move as they travel to work, stores and other destinations.

Napa County residents experience these hard, cold numbers every day where the rubber meets the road. If past trends are any indication, the number of drivers on Highway 29 and Silverado Trail will continue to grow in coming decades, at some locations more than others.

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Napa County Reporter

Barry Eberling covers Napa County government, transportation, the environment and general assignments. He has worked for the Napa Valley Register since fall 2014 and previously worked 27 years for the Daily Republic of Fairfield.

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