For Alaskans who regularly drive on the Seward Highway, delays can be a frustrating part of the journey. Crashes and construction are the most common reasons for traffic back-ups, but sometimes, more unusual circumstances lead to closures.

On Thursday, the highway was closed while a 60-ton boulder was cleared from the side of the road.

Crews spotted the rock Wednesday when they were cleaning up a rockslide. The boulder was in a precarious position on a cliff above the highway. The Alaska Department of Transportation used a high-pressure hose to erode the dirt underneath the rock, which caused it to fall onto the closed section of the highway below.

Taking action before a driver is hurt is the same philosophy behind the DOT’s construction project on the highway. Between mile markers 99 and 100, the northbound passing lane is being expanded by about one mile.

“It seems that most of the accidents you hear about are located in that area. It’s a very high crash zone,” said DOT spokesperson Jill Reese. “We target the areas that have the highest crash rates.”

That project is the first phase of a much larger effort to expand the highway between mile markers 99 and 105. The remaining five miles of reconstruction are slated to being summer of 2017.

“They’re totally reconstructing the road — adding lanes, adding turnout lanes, [and] a pathway — the works,” said Reese.

Much of the Seward Highway is a DOT Safety Corridor, where the agency makes an added effort to reduce the number of incidents that result in fatalities and serious injuries.

In 2015, there were four fatalities on the highway. One was within the corridor. Since 2006, when the corridor started, the number of crashes resulting in serious injuries or fatalities has fallen by 38 percent, according to DOT.

Reese said the Seward Highway is “a number-one priority” for the department, but ultimately people need to drive safely for the road to be less dangerous.

“If we considered a highway dangerous, we would close it. So it’s as safe as any other highway if you just drive for the conditions,” said Reese.

As of Thursday afternoon, the boulder was resting along the right-hand shoulder of the northbound lanes of the Seward Highway.

Reese said DOT maintenance and operations crews will be breaking it into smaller pieces on Monday morning so it can be moved out of the area. DOT will be closing one of the two northbound lanes for that process.

KTVA 11's Eric Ruble can be reached via email or on Facebook and Twitter.