(CBS) - In the wake of repairs to a sinkhole along the eastbound lanes of Route 422 in the King of Prussia area, PennDOT is planning nighttime and overnight lane closures there starting tonight for tests beneath the road surface.

PennDOT's Gene Blaum says for the next seven nights, one lane of traffic along Route 422 - sometimes eastbound, sometimes westbound - will be closed from 9 p.m. to 5 a.m. between the First Avenue interchange and the Pennsylvania Turnpike overpass in Upper Merion Township.

He says this will give road crews the ability to continue the investigation into areas under the road surface in the vicinity of that huge sinkhole which opened up on Oct. 1 and was repaired:

"Using radar and other devices to determine where voids are existing underneath the road surface. This will be followed up in early November with some drilling into the pavement and into the earth underneath the pavement."

Last weekend, Blaum says crews injected grout material underneath sections of the roadway to fill in voids that had been discovered during ongoing inspections after the sinkhole was repaired.

Reported by Mark Abrams, KYW Newsradio