ALBANY — The state will erect a safety barrier to reduce the number of wrecks that end up on Century Drive in Albany after they happen on Interstate 5.

A 3-foot-tall concrete slab will be installed on the east side of northbound I-5 parallel to Century Drive between the north Albany and Viewcrest interchanges, said Shon Heern, project manager for the Oregon Department of Transportation based in Corvallis.

The installation will occur in conjunction with a long-planned upgrade to southbound Interstate 5 to take place from the north Jefferson exit to exit 234B, the Highway 99E exit in Albany.

The $25-million project by Hamilton Construction Co. of Springfield started Monday night, he said. Crews are doing some freeway widening at the south Jefferson exit and are restriping a bridge near the exit to narrow the lanes so north and southbound traffic can be diverted onto the bridge. Detouring traffic will allow unimpeded work on that stretch of the freeway.

Traffic is being restricted to one lane at night while that work is done, Heern said.

During the entire project, lane restrictions will occur only at night to minimize traffic tie-ups. All work is expected to be completed in June 2006. Most of the improvements will happen during the 2004-05 summer construction seasons. However, the work zone will be active year-round.

Drivers in both directions can expect lane closures, short detours and narrowed lanes. Day and night work is anticipated.

The scope of the project includes repairing or replacing 14 bridges, and that accounts for more than half of the project cost, Heern said.

New ramps will be built southbound at the south Jefferson interchange, and southbound on-ramps will be built at the Ankeny Hill and Millersburg interchanges.

The southbound Hoefer Road exit will be closed permanently, and a new frontage road will be constructed on the west side of I-5 from Hoefer Road to the Dever-Conner interchange.

On the freeway, crews will grind up 6 inches of worn pavement, put it back in place and then top that with another 6 inches of paving, Heern said.

During the project, traffic will be diverted around some work zones by using the temporary lanes in the median. Those lanes already are in place.

The lanes, built to carry traffic during a similar northbound project, were not constructed to the standards needed to carry continuous freeway traffic loads, he said.

Consequently, the detour lanes cannot be used for any future freeway widening project. Once current work is completed, the lanes will be ground up and left in place.

A 6-foot-wide portion of that roadway, however, will be left. Eventually, a cable barrier will be strung along that lane to reduce cross-over wrecks.

Funds from the Federal Highway Administration and the Oregon Transportation Investment Act are paying for the restoration.

For the latest information on road work, watch for message boards along the freeway or go to www.tripcheck.com for updates.

Similar improvements to northbound I-5 were completed in 2001. Work on that $19.6 million, 6-mile upgrade started in 1999. The work included removing the asphalt that covered the concrete roadbed.

The concrete had been poured without any rebar and in panels, so with increased truck traffic and heavy loads, the roadbed had started to rock, creating cracks in the asphalt.

The project also included the closing of the Hoefer Road interchange (Milepost 237). The ramps were taken out and a new bridge was built on Higbee Road to provide a way in and out during periods of high water.

Farther north, the north Jefferson interchange was rebuilt with a new bridge and ramps.