Alternating one-lane traffic is directed past the new roundabout at Exit 16 as construction crews lay down an initial layer of asphalt defining the new lanes and center island of the intersection in Concord on Wednesday, Aug. 30, 2017. (ELIZABETH FRANTZ / Monitor staff)
Alternating one-lane traffic is directed past the new roundabout at Exit 16 as construction crews lay down an initial layer of asphalt defining the new lanes and center island of the intersection in Concord on Wednesday, Aug. 30, 2017. (ELIZABETH FRANTZ / Monitor staff)

The lanes and center island of the new roundabout in East Concord took shape Wednesday as construction crews added a base layer of asphalt to the graded dirt. Traffic was reduced to one alternating lane to accommodate the work and will continue into Thursday as initial paving wraps up.