WAILUKU, Maui — A Maui Circuit Court judge is expected to issue an order today requiring the state Department of Transportation to make intersection improvements in Kahului to accommodate increased traffic from the Hawaii Superferry, which begins interisland service Tuesday.

It is not known if the ruling by Judge Joel August could end up delaying the ferry service, which faces a greater threat from a separate case to be heard today by the Hawai'i Supreme Court over whether an environmental impact statement is required for $40 million in state-funded harbor improvements for the Hawaii Superferry.

If an EIS is ordered, the ferry could be postponed for months or even years while the study is conducted.

The case before August involves the Maui Tomorrow Foundation, the Kahului Harbor Coalition and Friends of Haleakala National Park, which are disputing an environmental assessment for a group of projects contained in the Kahului Harbor Master Plan 2025. One of the projects already completed is a bridge over a drainage canal that will be used by vehicles going to and from the ferry.

The judge ruled in May that the DOT's environmental assessment of the master plan projects was inadequate with respect to potential traffic impacts, and additional hearings were scheduled to discuss remedies.

Yesterday, August heard testimony on measures that might help keep traffic flowing at the busy intersection of Ka'ahumanu and Pu'unene avenues in Kahului. The vehicle entrance and exit to the Hawaii Superferry property is on a short northern spur of Pu'unene Avenue that also provides the only access to First Hawaiian Bank's main Maui branch and a restaurant.

The company estimates a total of 267 vehicles a day will travel through its Maui site, either loading or unloading from the 350-foot vessel or dropping off or picking up passengers.

To avoid peak morning commute hours, the Superferry set its Kahului Harbor arrival time for 9:30 a.m., with departure at 11 a.m. The company also plans to have employees regulate the number of vehicles leaving its site, with cars being held up on company property if necessary before being allowed onto the Pu'unene Avenue spur.

Company officials estimate it will take 15 to 30 minutes to get all disembarking vehicles on the road.

A traffic impact study prepared for the DOT by Fehr & Peers/Kaku Associates said the master plan harbor projects would create only "marginal increases" in traffic on nearby streets and that no mitigation was necessary.

Attorney Isaac Hall, representing the plaintiffs, called on California traffic engineer Edward Ruzak to dispute the assessment. A report by Ruzak, who often works in Hawai'i, said ferry-related traffic would have "significant negative impacts, which would include long lines, congestion and delays."

Testifying by a videoconference link from San Francisco, Ruzak estimated it would take 60 to 90 minutes to get vehicles from the ferry onto public roads under current conditions.

Ruzak offered recommendations that included hiring police officers to direct traffic during the two-hour period when the ferry would be processing vehicles for arrival and departure, and providing off-site parking for passengers who weren't taking their cars along and for motorists who didn't want to enter the ferry property to drop off or pick up passengers.

Ruzak also suggested reprogramming traffic signals to give ferry traffic more time to enter the main road, and reconfiguring the Ka'ahumanu-Pu'unene intersection to add turn lanes.

He urged that some of the measures be taken before the start of ferry service, not after problems have emerged.

Responding to a question from August, the traffic engineer said it shouldn't take more than a day to restripe the Pu'unene spur.

At the conclusion of the hearing, the judge indicated he would issue an order today with specific instructions on temporary traffic measures to be undertaken, although he didn't say which measures he was considering.

Another hearing was set for Nov. 8, at which time the judge may order further mitigation if it turns out the ferry service has created major traffic congestion.

DOT Director Barry Fukunaga said after the hearing that he believes there won't be a significant impact and that it would be premature to change the intersection without knowing whether there will be problems.

Maui Tomorrow president emeritus Ron Sturtz was doubtful the mitigation measures would work. He said traffic is "one small piece" of the concerns about the Hawaii Superferry, which include the spread of invasive species and collisions with humpback whales.

Reach Christie Wilson at cwilson@honoluluadvertiser.com.