HONOLULU -- Starting Tuesday morning, vehicles need three people to ride in the zipper lane.

It is a controversial move, but the state Department of Transportation insists it is necessary.

From 5:30 a.m. to 8:30 a.m., motorists need three people instead of two to drive in the zipper lane from Waikele to Iwilei.

"We believe we will be using the zipper and the Nimitz (Highway) contraflow much more effectively and efficiently," DOT Director Brennon Morioka said.

About 3,800 cars go through the zipper lane each weekday morning, officials said.

DOT officials said that when the zipper lane opened in 1998 there was a three-person minimum occupancy. In 2005, that changed to two people.

"We actually saw a slight increase in the number of cars, but we're seeing a lot less people using it," Morioka said.

DOT officials said riding in the zipper between 6:30 a.m. and 7:30 a.m. shaves up to 25 minutes of commute time. However, driving it from 5:30 a.m. and 6:30 a.m. actually adds 15 minutes to the commute. They hope the change saves time in the early morning.

Both TheBus and Van Pool Hawaii officials said ridership has gone up recently because of rising gas prices, and they expect more people to come on board because of changes to the zipper lane.

"We've been so successful that in the last couple of months. We running out of vehicles and money to put vehicles on the road," said Vicki Harris of Van Pool Hawaii.

Some drivers welcome the change, but others think it will make traffic more congested.

"We've been working closely with the Honolulu Police Department and they will have enforcement out there," Morioka said.

HPD said it is not beefing up the number of officers in the area, but said that police will be monitoring the zipper lane as part of their normal patrols.

For motorists who get caught violating the rule, it is a maximum $200 fine and a mandatory court appearance.