An electronic tollbooth system used on expressways was restored Monday after causing massive headaches for drivers and congestion at tollgates over the weekend due to a malfunction.

The Electronic Toll Collection (ETC) system, which electronically collects tolls, experienced technical glitches that were felt across toll roads in Tokyo, Kanagawa, Shizuoka, Yamanashi, Aichi, Mie and Gifu prefectures on Sunday, with Nagano added to the mix earlier Monday, affecting a total of 106 locations.

However, at around 2 p.m. on Monday, the ETC system was restored for all tollbooths after Central Nippon Expressway, the expressway operator, made emergency fixes.

The glitch began on Sunday morning, when payment using the ETC cards at tollbooths could not be completed, trapping vehicles behind the lowered gate bars.

This caused massive traffic congestion across central Japan on Sunday, which was compounded by the fact many people were returning from spring break or outings over the weekend.

Normally, gate bars at tollbooths rise after payment is automatically made via an ETC card reader inside the vehicle. During the ETC malfunction, the expressway operator kept the bars raised as a temporary measure and drivers were instructed on its website to pay the fee online later via a QR code found on the site.

“It is highly regrettable to have caused such trouble to users, and the transport ministry has asked the Central Nippon Expressway Company to promptly investigate the cause of the problem ... and take measures to minimize the inconvenience to affected users,” Chief Cabinet Secretary Yoshimasa Hayashi said on Monday. “We would like to instruct them to ensure that similar problems do not occur again.”

According to the company, the cause of the glitch remains unknown, although it is thought to be related to repair work on the ETC system in preparation for implementing a late-night discount on the expressways that started on Saturday.

It is the first time such a large-scale problem involving the ETC system has occurred since Japanese expressways were privatized in 2005.