Question: I’m curious about the sign on Pali Highway just past the start of Old Pali Road, going to Kailua, that says, "Trucks and buses use center lane from 5 a.m. to noon." What’s with that? Also, why is the maximum speed limit going down the Pali into Kailua 35 mph when the minimum speed in the opposite direction on the same road is 40 mph?

Answer: Bad vibes!

That’s the reason for the directive that trucks and buses stay the middle course while heading toward Kailua on Pali Highway.

It began many years ago when residents whose homes abutted the highway in that area complained about vibrations disturbing them, said Tammy Mori, spokeswoman for the state Department of Transportation.

They blamed the "phenomenon" on heavy trucks and buses.

"The DOT studied the issue for some time (but) could not pin the source of the perceived vibrations," Mori said.

To try singling out specific potential sources, the department decided to have a trial period restricting trucks and buses from using the far right lane during certain times of day to see whether there was an improvement in the situation.

"We are still evaluating the situation," Mori said.

If it’s determined that the restrictions aren’t resolving the problem, the signs will be removed, and the trucks and buses will be allowed back into the far right lane.

As for the speed limit in the Kailua-bound lanes on the Windward side of the Pali Tunnel, Mori said it was lowered to 35 mph from 45 mph "many years ago" because of accidents occurring in the downhill direction, especially at the hairpin turn.

The department conducted speed studies to evaluate the appropriate safe-driving speed in both directions along that stretch of highway.

Town-bound it was determined 45 mph was appropriate because it was uphill and drivers could better control their vehicles.

Kailua-bound, however, drivers were less able to control their vehicles at the higher speed as they headed downhill, Mori said. That was especially true in their response time to correcting their vehicles if they began to deviate from their lane.

Question: I live in Kaneohe, where they recently installed vine landscaping along Kahekili Highway, between Likelike Highway and Haiku Road. I notice that some of the vines have already died and a whole bunch of other vines are turning yellow. There’s something wrong – either they’re not being maintained with no water, or something’s killing them. Can someone check on this to make sure the plants are going to survive?

Answer: The state Department of Transportation is aware of the dying vines and trying to determine the problem, said spokeswoman Tammy Mori.

"The plants are being watered in appropriate amounts, so that does not appear to be the underlying issue," she said. "We are working with the contractor to investigate the problem, as the stress on the vines does not appear to be readily apparent."

Online, Long Time

The Board of Water Supply has been offering online bill payment for much longer than the two years quoted in a recent column (see hsblinks.com/2hj).

It actually began offering the service to 150,000 customers way back in 2001, a spokeswoman clarified.

Write to "Kokua Line" at Honolulu Star-Advertiser, 7 Waterfront Plaza, Suite 210, 500 Ala Moana Blvd., Honolulu 96813; call 529-4773; fax 529-4750; or e-mail kokualine@staradvertiser.com.