A subcommittee in the United States Senate will be probing how the National Highway Traffic Safety Administration handled the recall for the faulty ignition switches of General Motors.

The hearing, which will be held next week on Sept. 16, will be led by Senator Claire McCaskill.

Possible reforms that can be made to laws governing vehicle and highway safety will also be explored in the hearing, just as Congress is working on a long-term transportation funding bill.

McCaskill, who serves as the chairman of the consumer protection subcommittee of the Senate Commerce Committee, has already previously questioned top executives of GM over two hearings held last summer, including CEO Mary Barra.

McCaskill questioned why it took GM over a decade to issue a recall order for 2.6 million cars that had defective ignition switches, which have been linked to 13 fatalities. The ignition switches can be accidentally jostled out of the correct position, which potentially disables the airbags of the vehicle even during a car crash.

A former country prosecutor, McCaskill has been one of the most vocal critics of GM amid the crisis revolving around the defective ignition switches. Last month, McCaskill proposed a bill that will elminate the cap of $35 million on civil penalties that could be fined upon companies that are found in violation of vehicle safety laws, increase the funding of the NHTSA twofold, and make it possible for executives of car companies that delay recalls leading to deaths to be imprisoned for life.

Several other bills have also been introduced since GM issued a recall order for its faulty ignition switches, which look to solidify the capability of the NHTSA to serve as the safety watchdog for the automobile industry.

The hearing on Sept. 16 will have NHTSA acting administrator David Friedman again in the line of fire of McCaskill's questioning. Friedman had already been part of previous hearings on the issue when he testified in hearings held earlier by Congress.

McCaskill said that she will be examining the ability of the NHTSA in the identification of vehicular safety issues, along with the role that the agency played during the recall of GM's defective ignition switches.

"I'm interested in the capability NHTSA has to get at problems. They've obviously missed some big ones," said McCaskill in an interview with The Detroit News. "The part of NHTSA that is responsible for monitoring issues like [GM] - they haven't even asked for an increase in staff and cars have gotten a lot more complicated."