WEBVTT REPAIRS. SHANNON: BOB HAZEN JOINS US LIVE TO EXPLAIN HOW THIS WHOLE VAN WORKS. REPORTER: YOU CAN TELL BY LOOKING AT THE TUNNEL SOME PLACES ARE NOT IN THE BEST SHAPE BUT YOU CAN'T REALLY TELL IF THEY ARE IN FACT DANGEROUS UNDERNEATH. THIS NEW TECHNOLOGY THAT WE GOT A LOOK AT TODAY WOULD LET OFFICIALS SEE UNDERNEATH THE TOP LAYER OF THE TUNNELS TO SEE WHETHER IN FACT THERE NEED TO BE MOREY PAIRS DONE WITHOUT DAMAGING THE TUNNELS EVEN FURTHER. ALL OF THESE CRACKS INSIDE THE LIBERTY TUNNEL COULD BE SIGNS OF PROBLEMS, BELOW THE CONCRETE SKIN, BUT TO SEE ANY DAMAGE UNDERNEATH YOU NEED X-RAY VISION, THAT IS A JOB FOR THE BEN TRAITOR VAN. >> THE RADAR ANTENNA IS SENDING A SIGNAL INTO THE CONCRETE LOOKING FOR THE REFLECTIONS AND ECHOES FROM THE INSIDE OF THE CONCRETE WALL, WHICH PROVIDE THE CONDITION. >> THE COMPANY AND PENNDOT SHOWED OFF THE TECHNOLOGY TO TRANSPORTATION AGENCY OFFICIALS THROUGHOUT THE COUNTRY. IT'S NEW NOT IN REGULAR USE YET. IT USES GROUND PENETRATING RADAR ON A MOVABLE ARM TO LOOK FOR DAMAGE IN THE TUNNEL. IT'S A LOT FASTER THAN THE WAY IT'S USUALLY DONE NOW. >> USUALLY YOU GET OUT THERE WITH A HAMMER AND SOUND THE WHOLE WALL AND SEE IF THERE IS ANYTHING WRONG BEHIND IT. REPORTER: WHY SHOULD YOU CARE IN PENNDOT OR OTHER LOCAL AGENCIES USE THIS? THEY COULD DO THEIR REGULAR TUNNEL INSPECTION NASA NIGHT AND NOT MESS UP YOUR COMMUTE. >> YOU DON'T HAVE TO SHUTDOWN THE LANE OR THE TUNNEL. IT'S SAFER. IT'S FASTER. REPORTER: BUT IT IS MORE EXPENSIVE. THE OLD HAMMER METHOD COST ABOUT $51,000 TO INSPECT THE ENTIRE TUNNEL, THE RADAR AROUND $100,000. THE TUNNELS HAVE TO BE INCH SUCCESSED EVERY TWO YEARS BUT I'M TOLD IF PENNDOT BUYS INTO