Pennsylvania’s smoothest roads are in the northwestern part of the state, according to the International Roughness Index, which averages bumpy inches per mile.

PennDOT’s District 1, a six-county area that includes Mercer County, has posted the state’s best IRI scores each of the three years the index has been used to evaluate state roads.

Mercer County is a leader within the leading district. In 1999 the county had the second-smoothest state roads in the district behind Erie County, and the fifth-smoothest in the state.

Success using state money to make better roads has made the county a testing ground for new programs and developing technology that figure to make driving easier. The programs and technology are changing the way the district paints its lines, salts and paves roads, and keeps customers informed, said Jack Baker, district engineer.

What’s hot at PennDOT this year includes:

• New line-painting trucks. As well as putting more reflectors on roads and guiderails to better delineate roads, the state is using more durable line paint that contains light-reflecting glass beads. The glass beads "make the lines shine," said Baker.

  The trucks cost about $523,000 each, and carry 1,000 gallons of paint and 6,000 pounds of glass beads. They paint yellow and white lines with laser-guided help. The latex paint is heated to about 120 degrees before the beads are applied to the wet, sticky paint, which dries in less than two minutes. District crews annually paint more miles of lines than other state crews, and paint them about $8 per mile cheaper than the state average.

• Agility Program. The district’s efficiency painting lines is a reason municipalities are trading their services, such as using municipal staff and machines to cut brush along state roads, in exchange for Penn- DOT-painted lines on local roads.

  The "Agility Program," which encourages cooperation between PennDOT and local governments to cut costs and provide more services, was launched about five years ago at Sharon council chambers, said Donald L. Harpst, Mercer County maintenance manager for PennDOT.

• The state first used the zero-velocity spreader to fight snow-covered roads four years ago in Mercer County. The spreader gauges the salting truck’s speed and projects road salt the same speed in the opposite direction, dropping salt gently on the road and reducing a "bounce factor" that had wasted as much as 40 percent of the dumped salt in the past. Spreaders can be hooked up to standard salt trucks, and PennDOT is experimenting with other de-icing materials, Baker said.

• PennDOT’s Web site -- which can be found at the state site -- www.pa.us -- offers customers detailed information about current road conditions and what the department has to offer. Information about road conditions is transmitted from road sensors and camera feeds at several locations. Sensors are being developed that can improve road conditions without the help of road crews. The sensors can dispense road chemicals before a storm hits.