Hawaii's ignition interlock law, which forces those arrested for drunken driving to prove they are sober before starting their car, is on the books, but questions of cost could delay its implementation.

The bill under scrutiny, House Bill 981, puts the details into the bill after a year of study by a special committee, but in testimony this week, state and county officials said the program will be expensive.

“;Changes will not come cheap,”; warns Timothy Ho, chief deputy public defender, in testimony prepared for a Senate Transportation Committee hearing.

Under the law, a person arrested for DUI would have an ignition interlock device put on his or her car and would have to “;blow sober”; for the car to start. Under current law a DUI arrest results in a revoked or suspended license.

“;The legislation will drastically change the DUI climate in Hawaii,”; Ho said. “;Penalties will be increased and a probationary model introduced.”;

That worries the Judiciary, which will have to ramp up its staff, Ho said.

“;There will be an increase in court congestion, which may require adding judges, court staff and attorneys,”; said Ho.

Violators are supposed to pay for their own interlock systems, but indigents will be paid out of a state fund from a surcharge assessed when the interlock is installed.

Walter Ozawa, deputy administrative director for the courts, said the probation office would likely have to supervise 3,000 more offenders because of the interlock system. And a probation officer would have to monitor the interlock device, which downloads information about unsuccessful attempts to start a car after the owner has been drinking.

The courts say they do not have the staff to monitor all the people arrested for DUI. There were 6,975 DUI arrests in Hawaii last year.

“;We try to ensure public safety by focusing our resources on the highest-risk offenders, which include sex offenders, domestic violence offenders and serious drug offenders,”; Ozawa said, adding that monitoring DUI interlocks would take an additional 10 probation officers.

Sen. J. Kalani English, senate Judiciary Committee chairman, said he wants to see the law start now but also said there are worries about money.

“;The Judiciary's concerns are, whenever you ask any department to do a bit more work, they always say they will need more money. But it is obvious we need to do this,”; English said.

The measure also has the support of the state Health Department — if costs are not prohibitive — and Mothers Against Drunk Driving Hawaii.

The actual fate of the ignition interlock law will not be determined until the Legislature goes into conference committee meetings next month and decides whether the state has the money to afford it.