The safety requirements that led Toyota, Honda and other Japanese carmakers to falsify certification tests may be overly stringent and outdated given advancements in automobile design and technology, fueling calls for their review.

Despite revisions since the standards were enacted in 1951, regulations haven’t kept up with the times, Takaki Nakanishi, an analyst at Astris Advisory Japan, wrote in a report. Although Akio Toyoda, chairman of Toyota, apologized earlier this week for failing to take proper steps, he also pointed to gaps between tests carried out in the field and the procedures required during the certification process.

As government officials raided Toyota’s headquarters on Tuesday, the carmaker halted shipments of three cars: Corolla Fielder, Corolla Axio and Yaris Cross. Even so, the latest round didn’t include warnings over operational safety. There doesn’t appear to be any evidence of an "organizational cover-up at this stage” by the manufacturers, according to Nakanishi.