LITTLE ROCK, Ark. (AP) - Arkansas highway officials will close a major interstate ramp for 15 minutes at a time so crews can put down grass seed.

The work will be done Sunday morning at the Big Rock interchange in west Little Rock. The ramp between northbound Interstate 430 to eastbound I-630 will close off and on through the early morning.

Construction crews are rebuilding the intersection at a cost of $124 million - adding flyover ramps where there is now a cloverleaf. The grass seed will cover much of a hillside where workers uncovered a huge rock that gave the intersection its new name.

The interstate crossing is the state's busiest intersection. Work is expected to continue into 2014.

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