The brother and mother of a Japanese tourist couple who died from injuries suffered in a van rollover accident have filed a wrongful death lawsuit against several travel companies and the van's driver.

Makoto Hoshino, a younger brother to Junji Hoshino, and Masako Kimura, mother of Junko Hoshino, are suing Canyon Transportation, Inc., Canyon Transportation Charter Services LLC and Western Leisure, Inc, all Utah corporations. Also named as defendants are Japan-based Nippon Travel Agency Company, Ltd., and its U.S. subsidiary, California-based Nippon Travel Agency America, Inc., as well as van driver Yasushi Mikuni.

The Hoshinos, Japanese residents, came to the United States on vacation in August 2010. Their vacation package included a stay in Las Vegas that was followed by a four-day tour of national parks in southern Utah and northern Arizona, according to the lawsuit filed in 3rd District Court last week.

The couple died on Aug. 9 when the van they were traveling in with 12 other tourists hit a median north of Cedar City on Interstate 15, and rolled two-and-a-half times, the complaint states.

Junko Hoshino was ejected from the van and her husband, Junji Hoshino, was partially ejected. Both died from their injuries.

The lawsuit claims both branches of Nippon Travel failed to ensure safety through the other contracted companies. Attorney Terry M. Plant, representing Nippon Travel Agency America, Inc., said, "There is no evidence that my client as a travel agent had any involvement in this horribly unfortunate accident and we believe that the court will so rule when the facts are put before it."

At the time of the accident, neither Western Leisure nor Canyon Transportation had the required licenses to conduct interstate transportation, the lawsuit states.

Those two companies also hired an inexperienced driver, 26-year-old Mikuni, to do double duty as the tour guide and driver, which left no time for him to rest, the lawsuit alleges. The companies also are accused of failing to investigate the Mikuni's background.

The lawsuit claims that from the start of the day, Mikuni was extremely tired and drank energy drinks and chewed caffeine gum to stay awake. He also was reported to have had marijuana in his system while driving the tour group and failed to wear needed corrective lenses.

Attorneys representing Canyon Transportation and Western Leisure could not be reached for immediate comment.

In May, Mikuni pleaded guilty to three counts of operating a vehicle causing injury or death, all third-degree felonies.

The family members are seeking an unspecified amount in damages. The lawsuit marks the third filed against the companies and drivers in Utah state court.