Wildlife won't be the only reason to slow down while driving at Yellowstone National Park this summer/NPS, Diane Renkin

Delays of up to 30 minutes are expected daily this summer along portions of the Grand Loop Road at Yellowstone National Park, and one construction area near Indian Creek Campground will sometimes close overnight.

The most significant project is the second phase of improvement on the 16-mile stretch of road between Norris Geyser Basin and the Golden Gate area south of Mammoth Hot Springs. This 4.7-mile project will improve and widen the current 18- to 22-foot road to the Yellowstone standard of 30 feet. It will also add and improve pullouts, widen shoulders, and install safer parking areas. This project is the most significant upgrade to the road since it was first constructed in the 1920s, and will be completed in three phases over the next several years.

At night, the section of road between Roaring Mountain and the Moose Exhibit parking about two miles south of the Indian Creek Campground may be entirely closed. Visitors should expect nighttime closures will be in effect from 10 p.m. June 1 to 7 a.m. Sept. 11. When night closures occur, travel from Mammoth to Norris would have to be done via Tower, Dunraven Pass, and Canyon. The Indian Creek Campground will not be affected by this closure.

In the fall, this section of road will close to all traffic from 10 p.m. Sept. 11 to 7 a.m. Oct. 7. The Grizzly Lake, Solfatara, and Mount Holmes trailheads will be closed during this period.

There will be no daytime traffic delays or overnight road closures on Fourth of July weekend (5 p.m. July 1 to 7 a.m. July 5) or Labor Day weekend (5 p.m. Sept. 2 to 7 a.m. Sept. 6).

Other construction projects causing short delays include the Glen Creek Stock Trailhead Parking Area south of Mammoth Hot Springs, and chip sealing throughout the park.

All other park roads and all park entrances are open for the season.