EAGLE COUNTY, Colorado — Labor Day weekend is all about laid-back picnics, leisurely hikes — and, potentially, sluggish traffic on Interstate 70.

The weekend tends to bring a spike in traffic on the highway, as Denver travelers head into the high country for a final hurrah.

“It's the last traditional weekend of summer, and so you've got people who are going up and spending the weekend in the mountains,” Bob Wilson, a spokesman for the Colorado Department of Transportation said. “We see it for hiking and biking and just getting out of the city before the snow flies.”

Given that, traffic might not be flying.

Matt Darpli, owner of a private car service in Avon called Eagle Vail Express, predicts traffic could be heavy on Sunday after 1 p.m.

“I would say it's going to be busy on Sunday no matter what,” he said. “People are going to think they're going to avoid the rush and go back to Denver and have Labor Day back there.”

If he had to guess, Darpli thinks the typical 2-hour trip from Vail to the Denver airport will drag out to three hours on Sunday.

If traffic gets really heavy over the weekend, CDOT could put traffic stops into effect at Eisenhower tunnel, Wilson said. In that case, lights on the tunnel would stop eastbound traffic for 20 minutes at a time at the tunnel's opening, so traffic to the east of the tunnel can clear out.

“There's a good chance we'll have those kinds of operations in place Monday afternoon,” he said.

Traditionally, Friday and Monday bring the most traffic over Labor Day weekend, Wilson said.

Last year, a total of 172,839 cars drove through Eisenhower tunnel over Labor Day weekend. Traffic spiked to 46,551 cars on Friday, then dipped back down to 41,881 cars on Saturday and 40,106 cars on Sunday. The number of cars through the tunnel climbed back to 44,301 cars on Monday.

Staff Writer Sarah Mausolf can be reached at 970-748-2928 or smausolf@vaildaily.com. The Associated Press contributed to this story.

I-70 construction update

All construction projects between Vail and Denver will be suspended over Labor Day weekend. Several ongoing projects are set to resume once the weekend ends, though.

1) Where: Top of Vail Pass to 5 miles west of the top

When: Tuesday through Thursday

Times: 8 a.m. to 4 p.m.

Why: Workers are removing sand from basins alongside the road, which requires parking trucks on the bike path.

Expect: 10-minute traffic stops for cyclists. Bike riders should plan for delays getting over the pass.

2) Where: Silverthorne to the Eisenhower tunnel

When: Weekdays from Tuesday through sometime in November

Times: 7 a.m. to 8 p.m. Mondays through Thursdays; 7 a.m. to 2 p.m. Fridays

Why: Workers are replacing the median

Expect: Drivers will see one lane closed going westbound, eastbound or both, depending on the day. Westbound and/or eastbound traffic will be reduced from three to two lanes.

3) Where: A mile west of Eisenhower tunnel.

When: Tuesday through sometime in November.

Times: 24 hours.

Why: Workers are stabilizing a slope alongside the highway.

Expect: I-70 westbound will narrow from three to two lanes along a roughly 200-foot stretch.

4) Where: Loveland bridge

When: Late Tuesday night through mid-October.

Times: 24 hours.

Why: Workers are replacing the concrete on the bridge.

Expect: One lane in each direction will be closed for about five weeks. “Delays are possible, especially on weekends,” CDOT spokesman Bob Wilson said.

5) How many cars drove through the tunnel?

August: 1, 088,706, (35,120 per day on average)

July: 1, 225,116, (39,520 per day on average)

August 2009: 1,164,895

July 2009: 1, 225,605

— Source: CDOT spokesman Bob Wilson.