Thumbnail photo: Jaime Matteoli, Caltrans' Last Chance Grade corridor manager, and Caltrans District 1 Director Matt Brady visit with Japan's Ministry of Land Infrastructure, Transport and Tourism during a recent visit. | Photo courtesy of Chris Howard. Above: Caltrans chose a 1-mile long tunnel out of several alternatives for rerouting U.S. 101 around the slide at Last Chance Grade. | Image courtesy of Caltrans District 1 Jaime Matteoli returned from his Japan trip excited about the ongoing collaboration he hopes to have with his counterparts at that country’s Ministry of Land, Infrastructure, Transport and Tourism. Matteoli said he hopes to gain some wisdom from the lessons his colleagues across the Pacific have learned as Caltrans begins refining its design for the 1-mile long tunnel at the Last Chance Grade landslide south of Crescent City. But he called the trip special for another reason: The Japanese people still remember the role a handful of Del Norte High School students played in bringing a 20-foot fishing vessel home to Rikuzentakata two years after the 2011 tsunami. “To stand by Kamome and visit the site of Rikuzentakata — it was on our way past the tunnel project in the Sanriku expressway — I felt proud of our community, proud of the youth,” Matteoli told Redwood Voice Community News on Monday. “It all started with young people providing an act of kindness to the people of Japan. We heard from many people, including the vice minister of MLIT, who expressed gratitude for their support.” Matteoli, Last Chance Grade corridor manager, and Caltrans District 1 Director Matt Brady visited Japan with Del Norte County supervisors Chris Howard and Darrin Short for about 10 days, returning home on Nov. 20. Matteoli noted that while the United States has built more than 500 highway tunnels, Caltrans has only built two in the last 20 years. “Japan has over 11,000 highway and road tunnels constructed,” he said. “They’re very good at constructing them and maintaining them. The high numbers provide a lot of lessons learned. We were particularly interested in tunnels built in seismically active areas and in tunnels with complex geology, which we have at Last Chance Grade.” That complex geology includes earthquakes, landslides and a high groundwater table, Matteoli said. The coastal stretch of U.S. 101 about 10 miles south of Crescent City has been plagued by landslide activity for decades. Nearly a year and a half ago, Caltrans decided that building a 6,000 foot tunnel around the landslide was the preferred alternative out of seven, though that carries a $2.1 billion price tag. Construction is expected to start in 2031. The proposed tunnel would be the longest Caltrans has ever constructed, according to a June 13, 2024 news release announcing the project. Howard described the geological similarities between the Del Norte Coast and Japan’s Tohoku Region — the epicenter of the 2011 Great East Japan Earthquake — as uncanny, especially when it comes to slope stability. It was this similarity, and the knowledge that Caltrans representatives had been looking to Europe for insight into tunnel building, that prompted Howard to introduce Matteoli and Brady to Rikuzentakata delegates Futoshi Toba, Akihiko Ito and Kyoshi Murakami at a Rural County Representatives of California meeting last year in Sonoma County. According to the Del Norte County District 3 supervisor, Japan had just finished rebuilding the Sanriku and National Road 350 highways that included 18 tunnels, many of which were about 2 miles long. “We just don’t do this in the U.S. anymore and we have a lot to learn,” Howard told Redwood Voice. “And so that’s where this idea was hatched that we really need to look at our counterparts and so we spent the last year and a half developing a pathway for that visit to take place.” Howard said it was thanks to Murakami and his connections with the Japanese central government that allowed the meetings between Matteoli, Brady and officials at the MLIT to take place. Matteoli said he and Brady visited the Tokyo Outer Ring Road project, which includes two tunnels. Constructed in an urban setting, Matteoli said that he and Brady visited because the boring machine the project uses may be an option for the Last Chance Grade project. Another tunnel Matteoli and Brady visited near Fukushima is using a sequential excavation method of construction Caltrans is proposing to use for the tunnel at Last Chance Grade. That project dealt with similar groundwater issues as well as varying hardness levels of the surrounding rocks. Japan also had to come up with a way to mitigate for sound since the tunnel is near homes, Matteoli said. “They built sort of blast doors that would dampen the noise,” he said. “It’s interesting for us because we have noise concerns with sensitive species in the area, so seeing that tunnel was hugely relevant.” The Last Chance Grade tunnel project will be going through its value engineering process starting next year. According to Matteoli, this means that Caltrans will be looking at ways to improve the current design as well as to find potential cost savings. The insights he and Brady gained in Japan will be useful. One lesson Matteoli took from a tour of Shin-Kyutai Tunnel on the Sanriku Coastal Road is the construction of a smaller tunnel that could be used for emergency vehicles and to facilitate evacuation of the tunnel itself. Caltrans has proposed running a smaller parallel tunnel alongside the larger Last Chance Grade Tunnel, Matteoli said. This would allow engineers to do geotechnical investigations during construction. Caltrans now has the idea of making a “pilot tunnel” a permanent feature of the structure. “You could use it to accommodate bicycles and pedestrians,” he said. “You could have a pilot tunnel used for emergency response and evacuation capacity similar to the Sanriku Coastal Road. We will explore those design alternatives in the value engineering process next year” According to Short, their most recent visit to Japan comes as the nation puts a lot of its resources toward increasing trade with the United States. The sister city relationship between Crescent City and Rikuzentakata included some economic investment — SeaQuake Brewing made Kamome Ale and Rumiano Cheese created Kamome Dry Jack — but the new relationship between Caltrans and the Ministry of Land Infrastructure Transportation and Tourism is a new chapter, Short said. “We’re just going to do our best to keep trudging along and try to foster those relationships,” he said.