WEST LEBANON — Motorists on Interstate 89 Northbound near Exit 20 in West Lebanon should expect delays through Thursday as crews work to reroute lanes onto a new bridge spanning the Connecticut River. The two-lane highway will be down to one lane beginning at the Exit 20 northbound ramp and continue through the Vermont state line, according to a news release from the New Hampshire Department of Transportation. The Exit 20 northbound on ramp will stay open. “Rolling roadblocks will be required to complete the work,” according to the release. “Road users should remain alert while traveling through the construction zone and obey all posted signs,” according to the release.