According to the 2005 Urban Mobility Report of the Texas Transportation Institute, traffic delays from roadwork in the United States cost $US6.3 billion and were responsible for 370 million lost man hours.

A survey conducted in 2002 by the Ontario Ministry of Transportation in Canada, found that road congestion cost businesses in the Toronto region approximately $US2 billion a year in lost time and productivity, primarily due to delays caused by truck deliveries.

But this is not just a North American phenomenon. In Japan, the time loss attributable to traffic congestion is as much as 30 hours per person annually. Worldwide, traffic disruption due to utility maintenance or roadwork has reached a stage where it affects not the functioning of entire national economies.

Recently, two New York based gas distribution companies, Keyspan Energy Systems and National Grid, adopted a new technology for gaining access to their underground plant that has wide application for other utilities worldwide. It is called keyhole coring and reinstatement and allows repair work from the surface of the road using long handled tools through an 18 inch keyhole cored through the pavement. The result is better service for customers, reduced traffic disruption and a safer work environment. It also results in significant savings to the utilities from reduced paving budgets and less damage to the road surface.

The process, which involves a specially designed truck-mounted or skid-steer-mounted coring unit from Utilicor Technologies that cores an 18 inch diameter hole through all kinds of asphalt, asphalt-concrete and reinforced concrete road systems and sidewalks, enables crews to vacuum excavate and view subsurface activity, or repair underground plant from the road surface using long handled tools. It was developed by Enbridge Gas Distribution of Toronto in the early 1990s and has been in use there for more than 15 years.

After the underground repair has been completed, the hole is backfilled to the level of the base of the pavement and the core or ‘coupon’ that was originally cut from the pavement, is reinserted back into the road surface where it is permanently bonded by a special proprietary adhesive called Utilibond™, that creates a bond stronger than the original pavement, and is able to support a single axel weight of more than 50,000 pounds.

Rotary coring facilitates utility access and is a key cost-saving element in the growing trend to keyhole technology. It also has direct application to other utility service and trenchless operations including: test holes; service drops and shallow splice pits; daylighting and bore-gel blow-out holes; and inspection holes for pipeline integrity and subsurface utility engineering.

Rotary coring and reinstatement can literally pay for itself within six to eight weeks from paving budgets and cost savings on road cut fees. One-stop, same-day coring and pavement reinstatement means improved logistics for both the utility and its contractors, with simplified crew scheduling, no temporary patching or repaving and no repeat site visits.

In New York City, Keyspan Energy Systems got the go-ahead in March from the NYC Department Of Transport for an extensive keyhole coring and reinstatement program employing state-of-the-art Utilicor Technologies’ coring equipment and its permanent pavement-reinstatement, bonding compound, Utilibond.

“Our crews have been using the Minicor skid-steer coring attachment and Utilibond on a pilot basis for more that a year now, and have achieved impressive results. We have seen increased customer satisfaction. No more jack-hammers, no debris left behind to dispose of and no waiting for paving restoration. At the end of the day the only thing left to mark our presence is a small circle in the pavement that is almost invisible,” say Gerry Lundquist and George Mirtsopoulos of Keyspan Field Operations.

Because this is a faster and less intrusive process, it results in fewer complaints from municipalities about unsightly road cuts, sunken patches or weakened or failed roads and can be a source of positive community relations. It also allows municipalities to redirect scarce repaving budgets from small hole utility repair sites to pothole repair and major resurfacing requirements. It is a reliable, field-proven process with zero reported failures in more than 15 years and over 50,000 successful corings and reinstatements in tough urban climates.

Easy and simple to operate, the coring unit is physically less demanding than other pavement cutting methods. It eliminates the need for jackhammers, hand digging and backhoes and the reinstatement process is also simpler. Easy opening, pre-measured plastic pails means no more awkward measuring and mixing from fragile paper bags.

Trenchless rehabilitation procedures have revolutionised the utility construction industry. The process of keyhole coring and reinstatement takes that rehabilitation to a whole new level – the road surface. Like microsurgery, keyhole or small hole technology was introduced along with vacuum excavation to access underground plant with minimum surface disruption - and it is a technology whose time has come can mean that it is no longer relevant.