Doing laps around the parking lot atop Cadillac Mountain in Acadia National Park while frustratingly searching for an open space. On schedule en route to start your hike from the Glacier Basin Trailhead in Rocky Mountain National Park only to discover you didn't factor in the lack of parking. Stuck in bumper-to-bumper traffic inching its way around the 11-mile loop road through Cades Cove in Great Smoky Mountains National Park. These are some of the summertime pleasures in the National Park System.

We all want to enjoy our time in the parks, but with summer's traffic filling parking lots, crowding roads, and backing up the line at entrance stations, that enjoyment can be fleeting. To help you know where to avoid, or how to avoid, traffic snarls, here's a look at 10 parks that experience some of the worst summer traffic in the system.

Zion National Park, Utah

Zion's traffic woes are directly tied to the park's main attraction -- Zion Canyon -- and the 7-mile-long road that accesses it. Traffic routinely backs up at the park's entrance gate at Springdale, and the few parking lots you'll find quickly fill.

"I visited on a Saturday and spent close to 40 minutes circling the Visitor Center parking lot for a parking spot," a visitor from Virginia wrote on Tripadvisor on June 13.

"The past three days, before 9:00 am - All available parking at the Zion Canyon Visitor Center is full and the parking area is closed. Park in Springdale and use the shuttle to reach the Visitor Center. Please park legally and responsibly," is a typical summer tweet from the park staff.

Solutions: Head into the park shortly after sunrise, do take advantage of the park shuttles, use the Kolob Terrace Road to access the high country and take some of the hikes there. Normally, the Kolob Canyon Entrance is another less-crowded option, but this summer, construction will restrict access there into the fall.

Grand Canyon National Park, Arizona

Far and away, most visitors to Grand Canyon head to the South Rim, and far and away, the greatest traffic problems are at the South Rim. They become multiplied when there are construction projects in the park.

"Why wait in lines and drive in circles looking for parking? During Spring Break, summer, and fall weekends, lines are long at the entrance station and parking is difficult to find on the South Rim," the park staff note.

Solutions: Park in Tusayan and ride the park shuttle onto the South Rim, visit the far-less crowded North Rim, take the train to the South Rim, detour to the Needles District of Canyonlands National Park.

Acadia National Park, Maine

So bad is the traffic at Acadia that park staff are working on a traffic management plan, but it won't be in place to help you this summer.

"Crowds of visitors in the summer and, increasingly, into the fall and spring are making it difficult for people to experience the best of Acadia. Crowded conditions in the park also cause safety hazards," park staff note on Acadia's website. "Always visit Acadia with a back-up plan. If a parking lot is full when you arrive, please keep going and try a new destination."

Solutions: Experience Acadia from the water with a guided kayak trip, take to Great Long Pond or Jordan Pond with canoe, or even Somes Sound if you're experienced dealing with tides, sign up for the 5-hour ranger-led tour to Baker Island, visit the remote Schoodic Peninsula.

Rocky Mountain National Park, Colorado

With just one road that crosses this mountainous park, and which leads to trailheads, overlooks, and other points of interest, Rocky gets crowded quickly in summer and early fall. The Bear Lake area is arguably the most popular destination in the park, due in part to its picturesque lake and the many trailheads there. But the parking lot can handle only so many cars, and quickly fills. "Until congestion is relieved: Restricted Vehicle Access on Bear Lake Road from Moraine Park to Bear Lake," is often tweeted by park staff in summer.

"Clearly sometime in the fairly near future, [the National Park Service is] going to reach a decision on what they're going to do with their traffic problem," Estes Park Mayor Todd Jirsa said at a public meeting in mid-June. "It's probably going to be something along the lines of limiting access to our national parks."

Solutions: Visit the west side of the park and hike into the park's interior from there, head out at daybreak for Bear Lake or your other chosen trailhead, utilize the park's shuttles.

Arches National Park, Utah

As with many other parks, Arches has a traffic problem, and is working on a long-term solution. But until that's in hand, you might run into long lines at the park's entrance gate, you might not find a place to park for the hike to Delicate Arch, and you might be frustrated trying to find a parking spot at Devils Garden. With a very limited road system, built around the 18-mile-long main road, traffic can quickly slow to a crawl during the spring, summer, and fall seasons at the park's main attractions, such as Delicate Arch, the Windows Section, and Devils Garden.

Solutions: Visit the nearby Island in the Sky District of Canyonlands National Park, head into Arches after 6 p.m. with a picnic dinner and plans to hike to Delicate Arch to watch sunset and the star show overhead, plan to visit in February.

Glacier National Park, Montana

Only the Going-to-the-Sun Road crosses Glacier National Park, and so that's where you'll encounter traffic jams and parking areas filled to the brim. Avalanche Lake trailhead? Yep. Logan Pass parking area? Absolutely. Jackson Glacier Overlook? You can count on it.

"Glacier National Park is just not designed to carry more visitors than Yellowstone,” Glacier Superintendent Jeff Mow told a local newspaper early in June.

Solutions: Plan a backpacking trip, go north into Canada to visit Waterton Lakes and Banff national parks, explore the Flathead National Forest.

Muir Woods National Monument, California

Until recently, this was a motorist's nightmare. Parking your car on the road shoulder a mile or two from the park entrance wasn't unheard of. The Park Service addressed this problem with a traffic management plan, which requires reservations for all personal vehicles and shuttle riders visiting the national monument. That can be a bit of a hassle if you enjoy spontaneity, but in the long run, this is the type of solution you can expect more and more parks to adopt.

Solutions: Make a parking or shuttle reservation, six months out from your planned visit reserve a cabin in adjoining Mount Tamalpais State Park and hike into Muir Woods for the day.

Yosemite National Park, California

Parking attendants, parking reservations, and redesigned parking areas all have been tried in the Yosemite Valley, but getting into the valley, finding a parking spot, and then getting out of the valley, can still be frustrating.

"If you’re visiting Yosemite — particularly Yosemite Valley — in summer, expect extremely high visitor concentrations, resulting in extended traffic delays, extremely limited parking, busy trails, and no lodging or campground availability. Expect delays of an hour or more at entrance stations and up to two to three hours in Yosemite Valley," the park notes.

Solutions: Take public transportation to the valley, and then utilize the free shuttles, visit the high country along the Tioga Road, head to Hetch Hetchy and enjoy the waterfalls and hiking trails there.

Yellowstone National Park, Wyoming

Traffic levels in recent years have prompted the park to build a new parking lot near the Fairy Falls Trailhead, and there can be times during the peak summer season where it could take a short while to get through the West Yellowstone or South entrance gates. But the real problem arises when you're in the park and someone spots a bear, a moose, elk, or bison near the road, and a traffic jam quickly materializes.

Solutions: Visit after Labor Day, travel U.S. Highway 191 north of West Yellowstone and utilize one of the park's traiheads there (the Bighorn Pass Trail follows a route once considered for another road into the park) for a hike, park your car and paddle into the wilderness on either Yellowstone or Shoshone lakes.

Cape Cod National Seashore, Massachusetts

Parking is limited at most of the seashore's beaches, and in some cases you're required to take a shuttle bus, a tricky proposition with beach chairs, blankets, umbrellas, coolers, and whatever else you like to haul to the beach. Perhaps the ugliest traffic situation you'll encounter while visiting the seashore is when you're heading home. Route 6 can have long bumper-to-bumper jams, particularly on Sunday evenings and holiday weekends.

Solutions: Leave for the beach early (or late) and take the bare essentials, explore Great Island on the Cape Cod Bay side of the seashore, visit after September or before Memorial Day.