Boise & Garden City

Oregon eclipse traffic is already backing up. Idaho has an app for that.

What you need to know about August's solar eclipse

This August, the U.S. will experience its first coast-to-coast total solar eclipse in 99 years.
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This August, the U.S. will experience its first coast-to-coast total solar eclipse in 99 years.

If you’re traveling to Idaho for the eclipse, pack your patience.

The state’s population may be increasing by 30 percent almost overnight — with some projections estimating that 370,000 to 500,000 people will be coming to a state that has 1.6 million people.

There will be delays.

Oregon is already seeing eclipse backups. On Thursday afternoon, traffic was backed up 30 miles on U.S. 26 and another road east of Prineville. An eclipse-themed festival in a remote area there is expected to attract 30,000 people.

In Idaho, travelers can stay up-to-date on the road ahead several different ways, including the state’s traveler information Web site:, or by calling 511.

That’s where you’ll find updated information on road conditions, delays and detours.

Caught in the crush of traffic around the state this weekend will be college students headed back to school, including the University of Idaho and Boise State University. Move-in day was Thursday at Idaho, and it’s Friday at Boise State. But students will be returning through the weekend. Classes start Monday at both schools.

Some of the messages on Idaho’s 511 site encouraged eclipse tourists to delay their return trip home to avoid getting stuck in a crush of traffic headed out of the state.

“If you can spend more time, do it, because it’s probably going to be less stressful for you,” said Vince Trimboli, spokesman for the Idaho Transportation Department.

You don't necessarily need fancy equipment to watch one of the sky's most awesome shows: a solar eclipse. With just a few simple supplies, you can make a pinhole camera that allows you to view the event safely and easily.

The transportation department aims to help keep travelers on their way by publicizing traffic counts at 24 different locations around the state, starting Friday. Find that online at

The largest influx of visitors is expected to come from points south via Interstate 15 in East Idaho, Trimboli said.

“That’s the closest most populated area. We expect to see a high volume of people coming from Utah,” he said, adding that there have been reports that Idaho is a top destination for people from California, Nevada and Arizona.

There’s a lot of construction on Interstate 15, so state transportation officials had a cellphone app created specifically for eclipse tourists to navigate the construction, Trimboli said.

They later decided to temporarily suspend construction on the interstate and restore all lanes of travel on Interstate 15 until after the eclipse, when construction will resume, Trimboli said.

If you are planning on shooting the eclipse with your smart phone, here are a few tips about using the approved solar eclipse glasses to ensure your safety, the safety of your phone and better photos.

“[The app] should still tell people where the heavy traffic areas are,” he said.

The app shows current and predicted travel times on I-15 between Utah and Montana, U.S. 91 from Chubbuck to Idaho Falls and U.S. 20 from Idaho Falls to Wester Yellowstone. It has a link to the 511 travel info site.

The app won’t work if you’re traveling over 5 miles per hour because state officials didn’t want people looking at it while driving.

“You have to check it out before you leave,” Trimboli said.

Travelers are also advised to pack extra food and water and to keep a full tank of gas.

How bad will traffic get in and around Boise?

That’s hard to predict but state transportation officials and other traffic analysts urge you to avoid Interstate 84 if you don’t need to be on it, particularly on Monday after the eclipse.

“If you think about a sporting event, or anything like that, people come at all times,” said Lauren Dominick, senior director of analytics and modeling for fleet management software developer Omnitracs. “But once it’s over, everyone tries to leave at the same time. That Monday afternoon is definitely going to be the most impactful.”

Trimboli said flaggers are on standby at several spots around the Boise region, including I-84 and U.S. 95, Idaho 55 and the Banks-Lowman Road (Idaho 17) and Idaho 21 and Banks-Lowman Road (Idaho 17). Elmore County has flaggers on standby at the interstate’s junction with Idaho 20, he said.

The heaviest traffic in the Boise region is likely to be on I-84 between Boise and Idaho Falls, Dominick said. She said Monday is likely to be busy all day.

Businesses should be prepared for disruptions, such as delayed deliveries. Travelers should prepare for outages that temporarily render GPS and cellphones useless.

Motorists who are on the highway when the eclipse happens are advised to pull off the road. Take care not to park in grass, as there is high fire danger.

Katy Moeller: 208-377-6413, @KatyMoeller

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