Lasting performance

By: 3M

By the end of 2006, the Missouri Department of Transportation (MoDOT) significantly improved 2,200 miles of its highest-volume roads under the state's Smooth Roads Initiative (SRI). "The project impacts a large percentage of drivers in Missouri," said Assistant State Traffic Engineer Mike Curtit, "and features safety enhancements in a visibility system that includes wider and brighter lane stripes and signs, rumble stripes and delineation of guardrails and barriers as well as better pavement."

Missouri voters approved the initiative in November 2004 to pay for aggressive road enhancements by redirecting funds to MoDOT. At the same time (January 2005), a snow-plowable raised pavement marker (RPM) was kicked up and caused a traffic injury. The incident prompted action. "We looked closely and found many loose RPMs so we began the search for an alternative system," said Jim Brocksmith, a technical support engineer at MoDOT. "The decision was to use 6-in.-wide 3M [Stamark] 380 tape on lane lines and epoxy-painted into milled rumbles at road edges."

"We were looking for a product that did well with daytime and nighttime presence, would perform better on wet nights and be durable enough to last for years," said Curtit. Of the nearly four million lineal feet of pavement marking tape MoDOT installed, about 25% is wet-reflective to provide that added performance. The current lanemarking application is grooved into specifications so the agency expects long life—up to eight years.

MoDOT weighed several factors that included performance and brightness as well as durability for a favorable life-cycle cost. Extra durability also improves safety because crews are not out as often.

"I know the cost to put down a stripe," said Brocksmith, "but what are the savings associated with increased safety, and what are the costs saved by motorists avoiding traffic disruptions?" Assessing the overall impact across the product life-cycle convinced MoDOT personnel that the cost is feasible and the system will save money over the life of the product.

"Don't let the up-front cost drive you away from using a more durable product," said Curtit. "It's an investment in your marking system that can be well worth it if it's applied on the right roadways—high volume, major facilities."

Missouri had the largest drop in traffic-related fatalities in 2006 of any state in the nation— down by 161 compared with 2005. A large part of the reduction is attributed to engineering advances such as the installation of median guard cable on the interstates, rumble stripes, smoother pavement, better and brighter signing, striping and reflective markings to help keep drivers on the road.