Anyone planning to celebrate the Fourth of July at Ala Moana Beach Park should prepare for an extra-large crowd this year, Honolulu Police Department officials said yesterday.

Between 40,000 and 50,000 are expected to attend the annual festivities, compared with the 25,000 to 40,000 who went last year. While the Ala Moana area has always been a popular spot for residents on Independence Day, more people will be out this year because the holiday falls on a Friday, said HPD Sgt. Deric Valoroso.

To handle the larger crowd, HPD will add 40 to 50 police officers to its usual area patrol team. Plainclothes and uniformed police officers will be on the lookout for violations of park prohibitions, including the use of fireworks or consumption of alcohol within the park.

Valoroso said officers will arrest people who break those rules.

"We're all here to watch the fireworks from the professionals, so let's leave the fireworks at home," he said.

Park entrances will be closed today at 10 p.m. Residents will be allowed in the park that evening, but no vehicles can be parked in the area overnight, Valoroso said. Gates will reopen 4 a.m. tomorrow.

In addition to park patrols, HPD will set up impaired driver checkpoints throughout the city from today to Monday.

Drivers who have had too much to drink should avoid hitting the road, HPD officials said.

To help prevent alcohol-related car wrecks, AAA Hawaii is offering a free "Tipsy Tow" service through tomorrow. Drivers can call 800-400-4AAA (800-400-4222) for a free tow home, up to seven miles. For distances farther than seven miles, drivers must pay the rate charged by the tow truck company.

"We want motorists to be aware of the high crash risk from drinking and driving associated with the holiday," regional manager Richard Velasquez said in a news release.

Even for those who don't plan on drinking this weekend, there are a host of other safety concerns to keep in mind.

The American Lung Association of Hawaii urges residents to stay upwind of barbecue and fireworks smoke, which can be harmful for people with impaired breathing.

Hawaiian Electric Co. also reminds people to stay away from overhead power lines when setting off fireworks. Interference with power lines can cause serious burn injuries from electrical shock, a HECO news release said.

Following the rules and "having aloha for others" will ensure a safe holiday for everyone, Valoroso said.

The Magic Island fireworks show, now in its 17th consecutive year, is one of 10 public shows islandwide that will take place tomorrow night.

High turnouts are anticipated for other shows as well, organizers say. Approximately 50,000 people are expected at the Army's Fourth of July Spectacular at Schofield Barracks' Sills Field.

The show at Ala Moana is the state's largest Independence Day fireworks display. Pyrotechnicians began setting up for the 20-minute show on Tuesday.

"We have a couple new things planned for this year," said Vern McGarry of Pyro Spectaculars by Souza, the company that has produced the show for over a decade. More than 1,850 shells will be fired during the show.

The fireworks display has been choreographed to match musical selections from "High School Musical," in addition to patriotic songs. During the show, residents can tune their radios to 94.7 FM to hear the songs, McGarry said.