Stuck in traffic jams, asking who's to blame? The answer depends on who you ask.

Yes, Ada County, traffic is getting more congested on your commute

Growth in the Treasure Valley since the economic recession of a decade ago has put a strain on existing traffic arteries in Ada County.
Up Next
Growth in the Treasure Valley since the economic recession of a decade ago has put a strain on existing traffic arteries in Ada County.

Jade Riley stood in front of an outsized map of Ada County that explained, he said, why Boise’s traffic woes will only worsen. He pointed toward five colored shapes of varying sizes — all congestion culprits, Mayor David Bieter’s chief of staff said, and all outside of Boise city limits.

They represented planned communities in unincorporated Ada County and Eagle. Alongside each was the number of dwelling units the developments were legally authorized, or entitled, to build: 11,474 new homes whose residents would flood the roads as they headed to work, to school, to shop in Boise, the capital of the fastest growing state in the country.

Riley began rattling them off: Cartwright Ranch, 620 units. Hidden Springs, 853. Dry Creek Ranch, 1,800. All in unincorporated Ada County northwest of Boise. “That’s a major contributor to downstream traffic,” he said. And Avimor, more than 800 units, "approved by the county. The city sued Ada County against this development. Again, downstream traffic.”

But these aren’t the only enclaves responsible for the burst of building after the Great Recession ended. In fact, just 1,230 or so of the authorized homes have been built so far, with about 50 under construction. As the Treasure Valley booms, Meridian has added far more people and cars than these five projects.

And so has Boise itself.

Boise officials are sensitive about this. The city has a seemingly permanent spot on U.S. “best of” lists. But lately the Boise area has drawn national attention for fast growth and municipal growing pains. Home prices have soared. Activists have organized to fight development that they say threatens to change their neighborhoods.

Riley's point is that Boise has sought to plan its own growth efficiently and to defend itself against harm from new planned communities north and northwest of, and not adjoining, the city.

But the modest impacts of those developments on traffic so far illustrate that the long-running feud between Boise and Ada County over them is just one part of the growth game. The more citizens and local governments know where growth is actually happening, the better they can handle it.

0617 growth glenwood.JPG
Commuters inch along Glenwood Street in Garden City in bumper-to-bumper traffic. Growth in the Treasure Valley since the economic recession of a decade ago has put a strain on existing traffic arteries. Darin Oswald

Boise adds 26,000 people since 2010

The Treasure Valley has two major engines of growth, said Carl Miller, chief demographer with the Community Planning Association of Southwest Idaho, the Valley's regional planning agency.

“Boise is still growing,” Miller said. “Meridian is growing more. ... Meridian has had 29 percent of the region’s [population] growth since 2010, and Boise’s had 24 percent. So, between those two, that’s more than half the growth.”

To be sure, Meridian's rate of growth has been much higher than Boise's, because Meridian's population base is smaller: 75,092 people in 2010, 106,410 today, according to COMPASS. Boise: 205,671 in 2010, 232,200 today.

The city held a series of workshops about growth, inviting residents to sign up for two-hour-long focused conversations in small groups.

A day before the first workshop on June 20, city staffers offered a 20-minute presentation to the City Council. Kyle Patterson, the city’s enterprise data strategist, flashed a series of PowerPoint slides with graphs of percentage growth since 1970. In the last 48 years, he said, Boise has grown three times as fast as the U.S. as a whole. Two slides later, he said the rest of Ada County has grown sixfold in the same period.

“The last thing I want to share with you is, a few weeks ago, the U.S. Census came out with their fastest growing cities for 2017, and we can see Meridian is on the list here,” Patterson said, displaying a chart with Meridian in the No. 10 spot.

0617 growth harris ranch02.JPG
Construction of homes in the Harris Ranch area of Southeast Boise boomed as the economy recovered from the 2008 recession, contributing to the city's recent population growth. Darin Oswald

Boise: We can do only so much

“But you have to go way down the list to see where Boise is,” he continued, scrolling down the chart on screen. “We’re actually the 183rd fastest-growing city. I bring this up not to say that we aren’t growing. We certainly are. I think this also illustrates that point again that most growth is happening outside of Boise in recent years.”

The result, Patterson said, is that there’s only so much Boise can do to manage the impacts of population growth.

City Council President Pro Tem Elaine Clegg was the first to speak after Patterson concluded. She wanted to know, she said, “if you’re going to make this point at some point: Boise only grew at 1.4 percent because we’re two and a quarter times bigger than Meridian, and at this point, we added 26,000 residents. They added 30,000.

“Twenty-six thousand residents is still a significant number of new people,” Clegg said. “I think it would be helpful for people to acknowledge that at some point.”

Some fear that the growth of planned communities outside of Boise will clog the city's already congested roads. So far, however, only about 1,230 of 11,474 legally authorized housing units have been built, with another 50 or so under construction. Provided by the City of Boise

Get to know the jobs-housing imbalance

Since the Great Recession ended in the Treasure Valley, the so-called jobs-housing imbalance has intensified.. That's how planners describe one of the chief generators of traffic. The more people who live in a different city than the one where they work, the more traffic they generate between home and job.

Builders put up more than 29,000 housing units in Ada County from 2010 through February 2018, according to the Ada County Assessor's Office. Of those dwellings, about 10,000, or 35 percent, were built in Meridian, and 9,000 or 31 percent, in Boise.

But Boise created more jobs: almost 15,000 of the nearly 29,000 created in Ada County from 2013 to 2017, compared with 9,500 in Meridian, according to the state Labor Department. Which is not surprising, because of major employers in Boise including state government, St. Luke's Health System, Micron, Albertsons and J.R. Simplot.

The number of homes has risen in smaller cities, too, adding to the daily commute-to-Boise rush: Eagle, 3,008 homes since 2010; Kuna, 1,525; Star, 1,507.

And the number of registered cars and trucks has jumped. Between 2010 and 2016, Ada and Canyon counties added nearly 72,000 vehicles, according to the Idaho Transportation Department.

Of the planned communities on Riley's list, Hidden Springs, where development began 20 years ago, already has more than 840 homes of 1,035 the county says are authorized (a higher total than Riley's tally), Avimor is less than half finished with more than 300 built, Cartwright Ranch is far from finished with about 50 homes built so far, and Dry Creek Ranch, the biggest, is just getting started. A petition drive aims to stop Dry Creek.

A fifth project could dwarf them all: the Spring Valley Ranch subdivision, approved 11 years ago on land Eagle annexed west of Avimor. The Dallas Police and Fire Pension System bought the land for $42 million in 2005 and hired Arizona-based M3 Cos. to develop it, but the project has stalled indefinitely amid a scandal over inflated values of the pension fund's investments. Although 7,160 housing units were authorized a decade ago, nothing has been built.

If all of the entitled units in Cartwright Ranch, Hidden Springs, Dry Creek Ranch and Avimor are built, they would have a big traffic impact, especially on thoroughfares such as State Street and Hill Road, which provide the most direct access from the first four projects to Downtown Boise. That's a big reason Boise has opposed each of them, Riley said.

0617 growth avemor.jpg
The Avimor planned community is developing on 23,000 acres north of Eagle along Idaho 55. More than 300 homes have been built so far. Ada County has authorized more than 800 homes in all. Kelsey Grey

And the busiest roads are ...

Today, the roads from Avimor and Hidden Springs to Boise are far from the region's busiest, according to the Ada County Highway District's most recent Traffic Counts report, published at the end of 2016. Those include State Highway 55, Hill Road, Hill Road Parkway and Seaman's Gulch Road.

State Street is another story. Around Collister Drive, Pierce Park Lane, Bogart Lane and Veteran's Memorial Parkway, it is among the county's busier throughways, with daily traffic counts of more than 36,000.

But the region's most traversed roadways serve drivers between Meridian and Boise. Eagle Road between Ustick Road and Overland Road carries between 37,000 and 58,000 vehicles each day, depending on the stretch. The approach to Interstate 84 sees more than 63,000 vehicles.

And that pales beside Interstate 84 itself. COMPASS calls I-84 and the I-184 Connector "the backbone to the Treasure Valley's transportation system." Between Eagle Road and the approach to Downtown, Compass estimates that I-84 carries 120,000 vehicles per day. "By 2035," the organization wrote in a 2013 report, "the travel demand on this corridor will double."

Keri Speirs, a commuter, has one word for life on the I-84: "Horrible!" When she leaves work in Boise at 5 p.m., "the drive to Nampa sometimes takes an hour and 20 minutes," she said. "I've been almost rear-ended twice this week with someone slamming on their brakes and sliding sideways behind me. It's frustrating and stressful.

0617 growth hidden springs2.JPG
HIdden Springs has attracted many homeowners who can have the luxury of living 20 minutes from Boise and still feel like they live in the country. Darin Oswald

Parking spaces get harder to find

Retired banker Carol Rivera says new Downtown stores and restaurants show that growth is "absolutely good," but also says the rising traffic has hurt the quality of life in her Near North End neighborhood. The neighborhood is “turning into a parking lot for the Downtown businesses and employers," she said.

Who's to blame?

Riley said Ada County commissioners' approval of Dry Creek Ranch, Cartwright Ranch, Hidden Springs and Avimor are worsening already congested North End. "This causes people to come down to here [and] flood into Harrison [Boulevard]," he said. Harrison is Boise's marquee residential street. With about 13,000 cars a day, it is busier than most other noncommercial roads.

County Commissioner Jim Tibbs, a former Boise city councilman, said it's not fair to blame the county and other Treasure Valley cities for worsening traffic. "We're all responsible," he said. "Boise, Meridian, all the cities. ... With all the people, it's just really stressing the system out a lot. And people are getting frustrated with it. They just say, make it go away or fix it.

"It took us a while to get here," Tibbs said, "and it's going to take us a while, I guess, to fix it.

0617 growth cartwright ranch.JPG
Bedroom communities like Cartwright Ranch, above, where dozens of homes have been built with hundreds more to come; and the adjacent Hidden Springs, which is mostly finished, are bringing more traffic to the Boise area, adding to some already congested roads. Darin Oswald

How the highway district manages growth

Craig Quintana, spokesman for the Ada County Highway District, agrees. "The bottom line is, growth is occurring all over the place, and the real question is, ‘How do we deal with it in the most efficient manner that allows people to live the life they want to live?’ ”

To that end, the highway district embarked on its busiest construction year ever in 2018, spending $61 million on about 90 separate growth-spurred projects, widening roads, improving intersections and adding miles of bike lanes. The next several years will bring more of the same, Quintana said.

Accommodating potential traffic from the planned communities, he said, is their developers' responsibility. Each big development must conduct a traffic impact study. From that, the ACHD requires improvements to the road system for projects to proceed. In addition, developers pay impact fees to mitigate strain to the transportation network.

At least 'it's not California'

Janell Hyer has seen the Treasure Valley change more intimately than most people. Hyer is 70 years old. She has lived in the Canyon County city of Nampa since 1948. She has commuted to Boise since 1970. She’s a research analyst with the state Department of Labor, where she has worked since graduating college, studying the region's changes in population and employment.

“Nampa’s my home,” she said. “It’s always been my home. [In years past] the commute was nothing. It’s gotten interesting over the years."

When she needs to get to work early, she said, she’ll leave home between 6:30 a.m. and 7 a.m. And if she doesn’t head out of work by 4 p.m. or 4:30, all bets are off.

“Some days I can get here in 20 minutes, 30 minutes,” she said, here being her office in Boise. “Some days, it takes me an hour. I adjust.”

Still, she said, “it’s OK. It’s not California.”

Maria L. La Ganga: 208-377-6431, @marialaganga