Honolulu’s roads affect its drivers daily, resulting in whispered curses against the city and state administrations. Sad to say, but Honolulu’s road conditions rank at the bottom in U.S. and are often worse than in developing countries. It is not that Honolulu does not have access to technology, standards, or machinery and equipment. The best of U.S. is available to Hawaii. But, something is missing.
First off, Honolulu has failed to realize that heavy rainfall here is the first culprit, which breaks down the bond between bitumen and aggregate. No matter that the best American asphalt mix proportioning is used, engineers should have realized a long time ago that the asphalt mixtures used in Honolulu are simply not dense enough for our weather conditions, which are unique in the U.S. Politicians may well point to costs to argue their way out of making denser mixes, but that doesn’t make the problem go away.
Which is why concrete has been long recommended in lieu of asphalt as a material of choice because concrete does not deteriorate under rain in the manner that asphalt does. If anything, good rain strengthens concrete as it ages. If the subgrade is built strong enough, concrete has always been known to have lower life-cycle costs than asphalt.
But the only reason this city does not use concrete in large scale is because its non-optimal politicians find concrete pavements more capital intensive than asphalt.
Yet, if Honolulu had adopted concrete as the standard for city roads 50 years ago, we would have been out of the woods by now, and would’ve had more to pay for rail or replace our aging drinking water pipelines.
But given that oil — and bitumen — could run out in about 30 years, as some predict, it is even more astonishing why we are continuing to invest in asphalt roads. It is perhaps because our elected leaders can’t look beyond their nose that they can’t look that far ahead. Yet, when the oil crisis hits, our asphalt roads will be the first to show distress. An asphalt future is simply unsustainable.
Which is why we should immediately start programs to replace asphalt roads and plan new technologies.
In the first stage, we need to use roller-compacted concrete in rural roads. The ride is quite OK, and brings expenses down.
Next, undertake a major campaign to replace less frequently used roads, driveways and parking lots with hard brick, as are used all over Western Europe. Not only do those roads look a pretty red, but they also are durable and sustainable, withstanding traffic loads efficiently. Expand brick to other roads, as we advance, and start moving the highways into concrete, bit by bit.
New technologies are inevitable in the near future — for automobiles using alternate fuels, if not driverless vehicles.
The new roads will look remarkably different: the stress on roads will be lesser as cars get smaller and lighter, meaning that roads can be cheaper. With driverless cars, traffic will be light and sparse, and so roads will be even cheaper but will use sensors and tracking stations. If we don’t start today, we will realize that 30 years pass all too soon, and then we’ll be the worse off for it.
While it is a perennial problem to make our leaders understand technology, electing good leaders is often more difficult than simply replacing asphalt with brick and concrete, which seems to be quite a problem in Honolulu, as it is.
Amarjit Singh is a civil engineering professor at the University of Hawaii-Manoa; the views expressed here are his own.
