An in-pavement crosswalk flashing light is to be operating in Kalihi in the next couple of months, the first of two midblock crosswalk safety demonstration projects scheduled this year.

Although long-planned, the projects come at a timely juncture. Two pedestrians were killed on O'ahu roads in the first three weeks of 2010.

The in-pavement flashing light will be installed along North King Street near the Kapālama Post Office, said Wayne Yoshioka, the city's transportation services director.

A notice to proceed was recently issued for the project, Yoshioka told members of the City Council Transportation Committee last week. The project is expected to cost less than $50,000.

How long it will be operating depends on the type of data the department gets back, Yoshioka said.

The state Department of Transportation tried an illuminated in-pavement crosswalk demonstration project along Pali Highway near Jack Lane in 2000. But while state transportation officials found the result mostly positive, they removed the in-pavement lights in favor of a full-scale traffic signal a year later.

The city, meanwhile, is selecting a contractor to put an overhead beacon flashing signal at a crosswalk in McCully fronting the South Beretania Street Times Supermarket near Hau'oli Street.

Installation of overhead beacons cost between $100,000 and $200,000, Yoshioka said.

The Transportation Committee pushed out a resolution urging Yoshioka's department to give more consideration to installing in-pavement flashing lights at nonsignalized crosswalks.

Yoshioka said he has no problem with the resolution but views it as unnecessary because his department is already conducting the demonstration projects.

He noted that some studies have shown overhead beacons are more effective than in-road signals, at least in some circumstances.

"The indications we're getting right now is that even though they're a little bit more expensive, the overhead ones are tending to operate a little bit better than the in-pavement ones," Yoshioka said.

The literature he's read states that overhead flashing signals tend to be more visible in all types of road conditions, while in-pavement signals may be obscured from motorists in heavy traffic, Yoshioka said.

"But it's not an either/or," he said. "I can see us using both of these tools."

Data gathered from the two projects will be used to determine when it might be appropriate to use either type of "traffic calming" device in other parts of the island, Yoshioka said.

With either device, pedestrians would have to press a button to trigger a signal. The city could have chosen that the signals be triggered by stepping into the crosswalk but national research suggests "having a pedestrian consciously push a button to actuate the signal is more likely to make the pedestrian check the street before entering the crosswalk," Yoshioka said.

Hawai'i Kai resident Natalie Iwasa expressed concern about in-pavement lighting in a letter to the council about the resolution.

"A disadvantage of in-pavement lighting is that pedestrians may have a false sense of security," she wrote. "Rather than spending thousands of dollars on these types of control devices, please consider increasing education and enforcement efforts," Iwasa wrote.