In its second decision in five months questioning police and prosecution methods in speeding cases, the Hawai'i Supreme Court has dismissed the "excessive speeding" conviction of a motorcyclist clocked at 70 mph in a 35 mph zone.

The court ruled there was insufficient evidence to prove the speedometer in the Honolulu police cruiser used to gauge the motorcyclist's speed was properly calibrated.

However, the court ruled that other evidence in the case, including testimony from the officer involved, was sufficient to uphold a conviction for simple speeding.

Honolulu Prosecutor Peter Carlisle said yesterday his office was analyzing the opinion and "talking to HPD to see what has to be done to implement the decision."

As in the aftermath of a similar Supreme Court decision last year on the accuracy of police laser guns used to measure vehicle speeds, Carlisle took issue with the latest ruling.

"I'm concerned that people are going to lose sight of the need to drive safely," he said. "I think we're being ruled by rules and not by law."

The ruling involving speedometer accuracy stemmed from a 2007 case that saw motorcyclist Zachariah Fitzwater charged with excessive speeding the night of May 9, 2007, on Kamehameha Highway near Waipi'o Uka Boulevard.

An excessive speeding charge is filed when a vehicle is traveling more than 30 mph over the posted limit.

Police officer Neal Ah Yat testified during Fitzwater's trial that he was parked on the roadside at 11:20 p.m. when a group of motorcyclists passed him "at an extremely high rate of speed."

Ah Yat pursued the motorcycles, and when he attempted "to pace them" using his speedometer, three of the bikers sped away but the officer was able to clock Fitzwater at 70 mph, according to court files.

Ah Yat said he checked his speedometer "at least three times" to confirm the speed.

The officer testified the accuracy of the cruiser's speedometer had been checked in August 2006 by a firm hired by the Honolulu Police Department. After calibration, the firm supplied a "speed check card" to be kept in the vehicle verifying the work had been done. The checks are valid for a year, Ah Yat said.

Fitzwater's public defender objected to the introduction of the speed check card, arguing that it was "inadmissible hearsay" unsupported by firsthand evidence of the calibration test.

State District Judge David Woo overruled the objection, saying he was "not gonna make any groundbreaking rules on that point until the Supreme Court rules on it."

The Intermediate Court of Appeals upheld Fitzwater's excessive speeding conviction, but the Supreme Court, in a 4-0 decision written by Justice Mark Recktenwald, overturned it. Justice Simeon Acoba wrote a separate opinion, concurring with the outcome but dissenting from some of the majority's reasoning.

The high court found that the speed check card should have been accompanied by supporting testimony or paperwork authenticating the accuracy of the police cruiser's speedometer.

Last year's decision similarly required police and prosecutors to produce additional verification of the accuracy of laser guns used in excessive speeding cases.

Ah Yat initially tried to use a laser gun on Fitzwater and his fellow motorcyclists but said he couldn't get a reading "because they were too small and because there were trees in the way."

In criticizing the laser gun decision last year, Carlisle called it "much to-do about nothing."

At the time, he said the ruling would "open the floodgates" to more litigation by people cited for excessive speeding, tying up the court system and costing taxpayers more money.