It’s the one thing that all parents dread while traveling.

It’s not the hand-to-hand combat and resulting recriminations from the back seat. It’s not the sloshing of drinks and spilling of snacks on the once-plush upholstery. It’s not the inevitable potty break five minutes after departing on a long journey.

No, it’s that question, always both plaintive and whiny, which slices through the solitude of making evasive maneuvers on the highway: “Are we there yet?”

(Do they think it’s any more fun watching the miles inch by a map? But I digress.)

Thanks to built-in videotape players, long trips with young children no longer require endless games of “I Spy” or “License Plate Hunt.” But distance is distance, and hours and hours are hours and hours. So, unless you actually enjoy chilling for long periods at McDonald’s PlayPlaces or Chuck E. Cheeses, a little advance planning is needed to find attractions for children that are both entertaining and educational (let’s be serious, it’s vacation, so fun naturally must come first).

So here’s some family-friendly attractions discovered on a recent trip to eastern Pennsylvania and New Jersey, all roughly within an hour’s drive of Philadelphia.

Philadelphia Zoo

America’s oldest zoo, opened in 1874, is located on the corner of Girard Avenue and 34th Street in the north end of Philly. It is home to 1,600 animals in its 42-acre Victorian setting. While most animals live in their own special areas, peacocks claim the zoo as their own, wandering about the property, periodically squawking their displeasure at all the people.

Special features of the zoo include the state-of-the-art PECO Primate Reserve, a children’s petting zoo, a Treehouse with interactive activities for youngsters and special educational programs.

An added-cost attraction is the Channel 6 Zooballoon, which rises 400 feet to give a panoramic view of the zoo and metropolitan Philadelphia itself. Also available for an additional fee are the camel safari and the pony-, elephant- and trumpeter swan-boat rides.

A new attraction this year is Safari Quest. The summer-long exhibit features African animals, wandering storytellers, live entertainment, a hands-on farmyard and a bustling marketplace. Children can follow along in their Safari Quest Field Guide, filled with games and fun facts.

A new show this summer is Soaring Safari, a free-flight bird show featuring eagles, hawks and vultures that soar into the sky and return to the arms of their trainers.

The zoo is open daily 9:30 a.m.-5 p.m. For more information, call (215) 243-1100 or access www.philadelphiazoo.org.

Six Flags

Located on Route 537 in Jackson, N.J., the 2,200-acre property features Great Adventure theme park, Wild Safari and Hurricane Harbor water park.

Great Adventure features 10 separate sections of rides and attractions spread over 240 acres. Two areas specifically target younger children: Bugs Bunny Land and Looney Tunes Seaport.

The big new attraction this year is the roller coaster Superman – Ultimate Flight. Passengers tilt face-first into flying position suspended from the track above. Strapped in harnesses and lap belts, they climb the 109-foot left hill. Reaching speeds in excess of 50 mph, the ride enters a series of sharp dives, highly banked curves and spirals, finishing with a 360-degree in-line roll.

In the 350-acre Wild Safari, visitors drive along a 41/2-mile road through 11 themed sections. More than 1,200 animals live at the park. Animals such as giraffes and ostriches come right up to vehicles and take a lick. One animal that visitors aren’t encouraged to see up close is the monkeys, which have been known to strip wipers, antennas and mirrors off cars. Using a bypass road is recommended instead.

The 45-acre Hurricane Harbor, which has a shorter season than the other two parks, offers water-based rides, attractions and activities.

Six Flags is open daily from mid-May through Labor Day and on weekends from early April to late October. For more information, call (732) 928-1821 or access www.sixflags.com/parks/greatadventure.

Crayola Factory

Here’s a place that allows children to color everywhere they can’t at home. Located in the historic Two Rivers Landing building in downtown Easton, Pa., the Crayola Factory not only shows how crayons and markers are created, but also gives kids a chance to use its products in every conceivable way.

Youngsters can choose to write on the curved glass walls at Inside Out, create books from their own stamped pages at the Easton Press & Bindery, build from modeling clay at Super Sculptures or color with melted crayons at Wax Works.

A collection of folk art from Binney & Smith’s Dream-Makers program is on display at the factory during Crayola’s 100th anniversary year.

A special exhibit featuring Miffy and Friends, the creation of artist Dick Bruna, will be on display through the rest of the year.

The Crayola Factory is open year-round, although hours vary. For more information, call (610) 515-8000 or access crayola.com/factory.

Thinking ahead

A little preparation can save a lot of time wandering down unfamiliar roads with hungry, tired children. Evaluate your family’s interests, then surf the Net. Among the resources to check on the Web are www.state.nj.us/travel (New Jersey); www.lehighvalleypa.org (eastern Pennsylvania) and www.pcvb.org (Philadelphia).