rudimentary
rudimentaryは「根本の，基本の」という第一義とともに，「未発達の，未熟の」，さらには「粗末な」という意味があります。ここでは「お粗末な目視検査」という意味合いでしょう。
日本のインフラはいつの間にか劣化が進んでいることを実感させられた痛ましい事故だったことが明らかになってきました。（UG）
Japan orders tunnel inspections after Sasago collapse
Japanese media report that the ministry of land, infrastructure, transport and tourism has ordered highway operators overseeing tunnels similar to Sasago to carry out emergency inspections.
The BBC's Rupert Wingfield Hayes in Tokyo says inspections of at least 20 tunnels of a similar age and design will now be carried out.
Japanese media say that for more than 30 years the company that owns Sasago had relied on rudimentary visual inspections there, with no reinforcement or repairs since construction.
Our correspondent says the new inspections will be more intrusive.
He says the focus of the investigation into the Sasago incident will consider why an inspection just two months ago did not spot anything wrong.
Motohiro Takamisawa, from Central Nippon Expressway (Nexco), which operates Sasago, said metal rod failure could have been to blame.
"At this moment we're presuming that the top anchor bolts have come loose," he said.
