Roads in Ehime That Close in Heavy Rain and Typhoons: Advance Closure Sections and Rain and Wind Rules on Expressways

On Days of Heavy Rain or Typhoon, Roads Close When Rainfall or Wind Speed Reaches a Standard

Some roads in Ehime are closed to traffic in heavy rain or typhoons before landslides or rockfalls happen. Road managers call this system “advance traffic restriction” (事前通行規制). The Ehime Prefecture page explains it like this.

事前通行規制とは、豪雨や地震などの異常気象時に、土砂崩れや落石等の恐れのある箇所を被害が発生する前に通行を規制することです。

Translation: “Advance traffic restriction means restricting traffic at places where there is a risk of landslides or rockfalls, before damage occurs, during abnormal weather such as heavy rain or earthquakes.”

Even after the rain stops, a road does not always reopen right away. This article takes in turn the roads managed by the prefecture, the national roads managed by the national government, the expressways and the Shimanami Kaido, and lists the standards for closing and the pages to look at during a trip.

The people who set the standards differ by type of road. The manager can also change on the way to one destination. When a forecast comes out, look up the roads you plan to use in the tables in this article.

National and Prefectural Roads Managed by Ehime Prefecture: 56 Abnormal-Weather Restriction Sections

The Ehime Prefecture road maintenance division page has a table of “advance traffic restriction sections in Ehime Prefecture.” There are 2 kinds of sections.

事前通行規制を行う区間には、一定の降雨量等に達した場合に通行規制する「異常気象時通行規制区間」と、気象・現地の状況等を判断して危険が予想される場合に通行規制する「特殊通行規制区間」があります。

Translation: “The sections where advance traffic restriction is carried out include ‘abnormal-weather restriction sections,’ where traffic is restricted when a certain amount of rainfall or the like is reached, and ‘special restriction sections,’ where traffic is restricted when danger is expected after judging the weather and conditions on site.”

The first kind, abnormal-weather restriction sections, number 56, and the page says this about the standard.

規制基準の一項目が基準に達した場合に通行規制します。

Translation: “Traffic is restricted when one item of the restriction standard reaches the standard.”

The “restriction standard” in the table has 3 columns: hourly rainfall, continuous rainfall and other. Even if hourly rainfall and continuous rainfall are not both reached, the restriction applies when any one item reaches its standard.

How to Read the Numbers in the Table

The hourly rainfall and continuous rainfall columns do not show a unit. The prefecture’s page for the Ishizuchi Skyline has this.

時間雨量40mm若しくは連続雨量200mmの降雨が観測された場合、通行止めを行いますのでご注意ください。

Translation: “Please note that the road will be closed if rainfall of 40 mm per hour or 200 mm of continuous rain is observed.”

The numbers are the same as in the row of Prefectural Road 12 from Tsuchigoya to the Wakayama Kanmon gate (hourly rainfall 40, continuous rainfall 200), so this article reads them as mm. The update date of this Ishizuchi Skyline page is April 1, 2021.

The national roads managed directly by the national government (Routes 11, 33, 56, 192 and 196) are not among the 56 sections in the prefecture’s table. They are covered in the next section.

10 National Road Sections (Sections Managed by the Prefecture)

The national roads managed by the prefecture that are listed are sections of Routes 197, 319, 378, 379 and 494. In the table, the section column gives the city or town in English, followed by the section as written on the page.

Route	Office in charge	Section	Length	Hourly rainfall	Continuous rainfall	Other
National Route 197	Yawatahama	Yawatahama: 八幡浜市大平～八幡浜市大平	0.5km	40	200	－
National Route 319	Shikokuchuo	Shikokuchuo: 四国中央市金砂町平野山～四国中央市具定町	4.5km	40	200	－
National Route 319	Shikokuchuo	Shikokuchuo: 四国中央市金砂町柳瀬～四国中央市金砂町柳瀬	1.3km	40	200	－
National Route 378	Yawatahama	Yawatahama: 八幡浜市大釜～八幡浜市真網代	1.0km	40	200	－
National Route 378	Seiyo	Seiyo (Akehama): 西予市明浜町田之浜～西予市明浜町狩浜	17.6km	30	200	Wind speed 15m/s
National Route 378	Ozu	Ozu (Nagahama): 大洲市長浜町須沢～大洲市長浜町須沢	1.0km	40	200	－
National Route 379	Chuyo	Tobe: 伊予郡砥部町川登～伊予郡砥部町川登	6.0km	40	200	－
National Route 494	Chuyo	Toon: 東温市問屋～東温市河之内（郡境）	13.2km	30	100	－
National Route 494	Kumakogen	Kumakogen: 上浮穴郡久万高原町笠方（黒森峠）～上浮穴郡久万高原町笠方（小網）	2.5km	40	200	－
National Route 494	Kumakogen	Kumakogen: 上浮穴郡久万高原町笠方～上浮穴郡久万高原町渋草	4.5km	40	200	－

The row for National Route 378 in Akehama, Seiyo (Tanohama to Karihama, 17.6 km) has a wind speed of 15 m/s in the “Other” column. This is a section where both rainfall and wind speed are standards.

46 Prefectural Road Sections

Route	Office in charge	Section	Length	Hourly rainfall	Continuous rainfall	Other
Prefectural Road 5 (川之江大豊線)	Shikokuchuo	Shikokuchuo: 四国中央市新宮町馬立辺地床～四国中央市新宮町馬立辺地床	7.6km	40	200	－
Prefectural Road 6 (高知伊予三島線)	Toyo	Niihama: 新居浜市別子山葛龍尾～新居浜市別子山登美野	3.3km	40	200	－
Prefectural Road 9 (大野原川之江線)	Shikokuchuo	Shikokuchuo: 四国中央市金生町切山～四国中央市金生町石ノ口	4.5km	40	200	－
Prefectural Road 12 (西条久万線)	Toyo	Saijo: 西条市中野丙（中野大橋）～西条市西之川乙（大宮橋）	20.7km	30	200	－
Prefectural Road 12 (西条久万線)	Kumakogen	Kumakogen: 上浮穴郡久万高原町土小屋～上浮穴郡久万高原町若山関門	18.1km	40	200	－
Prefectural Road 13 (壬生川新居浜野田線)	Shikokuchuo	Shikokuchuo: 四国中央市土居町天満～四国中央市土居町天満	4.8km	40	200	－
Prefectural Road 13 (壬生川新居浜野田線)	Shikokuchuo	Shikokuchuo: 四国中央市土居町野田～四国中央市豊岡町長田	0.9km	40	200	－
Prefectural Road 17 (北条玉川線)	Chuyo	Hojo: 北条市儀式風早橋～北条市庄府（郡境）	4.0km	40	200	－
Prefectural Road 17 (北条玉川線)	Imabari	Imabari: 今治市玉川町竜岡字原田～今治市玉川町竜岡字葛谷	2.0km	40	200	－
Prefectural Road 20 (松山北条線)	Chuyo	Matsuyama: 松山市長井方乙1551の1 ～松山市客	1.9km	40	250	－
Prefectural Road 28 (長浜保内線)	Yawatahama	Yawatahama: 八幡浜市日土町森山～八幡浜市日土町川辻	3.0km	40	100	－
Prefectural Road 30 (宇和三瓶線)	Seiyo	Seiyo (Mikame): 西予市三瓶町津布理～西予市三瓶町津布理	1.0km	40	100	－
Prefectural Road 32 (肱川公園線)	Seiyo	Seiyo (Nomura): 西予市野村町予子林～西予市町野村町予子林	7.0km	30	200	－
Prefectural Road 34 (平城高茂岬線)	Ainan	Ainan: 南宇和郡愛南町外泊～南宇和郡愛南町高茂岬	8.0km	40	200	－
Prefectural Road 36 (野村柳谷線)	Seiyo	Seiyo (Nomura): 西予市野村予子林～西予市野村町大野ヶ原	38.4km	30	200	－
Prefectural Road 36 (野村柳谷線)	Kumakogen	Kumakogen: 上浮穴郡久万高原町西谷（郡境）～上浮穴郡久万高原町西谷（中久保）	5.5km	40	200	－
Prefectural Road 47 (新居浜別子山線)	Toyo	Niihama: 新居浜市立川町（生子橋）～新居浜市別子山弟地	26.0km	40	200	－
Prefectural Road 126 (上猿田三島線)	Shikokuchuo	Shikokuchuo: 四国中央市富郷町寒川山～四国中央市富郷町豊坂	12.7km	40	200	－
Prefectural Road 137 (金子中萩停車場線)	Toyo	Niihama: 新居浜市星越町（金子橋）～新居浜市萩生	2.8km	40	200	－
Prefectural Road 142 (石鎚伊予小松(停）線)	Toyo	Saijo: 西条市小松町大字石槌字堂藪～西条市小松町大字石槌字黒川	3.1km	30	200	－
Prefectural Road 142 (石鎚伊予小松(停）線)	Toyo	Saijo: 西条市黒瀬～西条市氷見	2.8km	30	200	－
Prefectural Road 147 (石鎚丹原線)	Toyo	Saijo: 西条市小松町大字大郷字開～西条市小松町大字石鎚字湯浪	3.2km	40	200	－
Prefectural Road 152 (寺尾重信線)	Chuyo	Toon: 東温市山之内～東温市藤之内	3.6km	40	200	－
Prefectural Road 153 (落合久万線)	Toyo	Saijo: 西条市丹原町鞍瀬～西条市丹原町明河	10.6km	40	200	－
Prefectural Road 178 (湯山高縄北条線)	Chuyo	Matsuyama: 松山市九川字池田甲249-1 ～松山市横谷（横谷橋）	14.9km	40	200	－
Prefectural Road 195 (興居島循環線)	Chuyo	Matsuyama (Gogoshima): 松山市泊町甲203 ～松山市泊町甲421の1	3.7km	40	200	－
Prefectural Road 195 (興居島循環線)	Chuyo	Matsuyama (Gogoshima): 松山市門田町～松山市門田町	1.1km	40	200	－
Prefectural Road 196 (河中平井（停）線)	Chuyo	Matsuyama: 松山市川の郷（川の郷橋）～松山市小野町（源ヶ谷橋）	8.0km	40	200	－
Prefectural Road 204 (長井方堀江線)	Chuyo	Matsuyama: 松山市長井方乙1551の1 ～松山市東大栗町	3.3km	40	200	－
Prefectural Road 206 (上怒和元怒和線)	Chuyo	Matsuyama (Nuwa): 松山市上怒和～松山市上怒和（小学校）	0.9km	40	200	－
Prefectural Road 207 (三坂松山線)	Chuyo	Matsuyama: 松山市窪野町（改良終点）～松山市窪野町（市道分岐点）	2.2km	40	200	－
Prefectural Road 210 (美川川内線)	Chuyo	Toon: 東温市井内上～東温市井内下	2.6km	40	200	－
Prefectural Road 234 (大洲保内線)	Ozu	Ozu: 大洲市西大洲山辺～大洲市西大洲安場	1.0km	－	－	Kanogawa Dam discharge 1,000t/s, water level 4.7m
Prefectural Road 234 (大洲保内線)	Yawatahama	Yawatahama: 八幡浜市日土町瀬田～八幡浜市日土町尾之花	3.5km	40	100	－
Prefectural Road 234 (大洲保内線)	Yawatahama	Yawatahama: 八幡浜市日土樫の木～八幡浜市日土町川辻	1.0km	40	100	－
Prefectural Road 248 (瀬田八多喜(停）線)	Yawatahama	Yawatahama: 八幡浜市日土町瀬田～八幡浜市日土町瀬田	3.6km	40	100	－
Prefectural Road 252 (双岩停車場和泉線)	Yawatahama	Yawatahama: 八幡浜市釜の倉～八幡浜市谷	3.5km	40	100	－
Prefectural Road 298 (深浦港線)	Ainan	Ainan: 南宇和郡愛南町深浦～南宇和郡愛南町垣内	1.2km	40	200	－
Prefectural Road 300 (高茂岬船越線)	Ainan	Ainan: 南宇和郡愛南町高茂岬～南宇和郡愛南町武者泊	6.0km	40	200	－
Prefectural Road 302 (皿ヶ嶺公園滑川線)	Chuyo	Toon: 東温市大字明河624 ～東温市大字河之内	6.9km	40	200	－
Prefectural Road 328 (柳谷美川線)	Kumakogen	Kumakogen: 上浮穴郡久万高原町大字西谷～上浮穴郡旧柳谷村・旧美川村村境	9.5km	40	200	－
Prefectural Road 332 (篠山公園線)	Ainan	Ainan: 南宇和郡愛南町（旧一本松国有林69林班）～南宇和郡愛南町正木御在所	12.8km	40	200	－
Prefectural Road 338 (岩城弓削線)	Imabari	Kamijima (Yuge): 越智郡上島町弓削三ツ小島～越智郡上島町弓削太田（弓削大橋）	0.6km	－	－	Motorcycles: wind speed 15m/s; vehicles: wind speed 25m/s; freezing
Prefectural Road 338 (岩城弓削線)	Imabari	Kamijima (Yuge, Ikina): 越智郡上島町弓削佐島～越智郡上島町生名（生名橋）	0.5km	－	－	Motorcycles: wind speed 15m/s; vehicles: wind speed 25m/s; freezing
Prefectural Road 338 (岩城弓削線)	Imabari	Kamijima (Ikina, Iwagi): 越智郡上島町生名～越智郡上島町岩城（岩城橋）	1.5km	－	－	Motorcycles: wind speed 15m/s; vehicles: wind speed 25m/s; freezing
Prefectural Road 339 (粟井浅海線)	Chuyo	Matsuyama: 松山市萩原字すべり石甲393 ～松山市萩原字柿成	1.5km	40	200	－

In the row for Prefectural Road 234 from Nishi-Ozu Yamabe to Yasuba in Ozu, there is no rainfall standard, and the “Other” column has a Kanogawa Dam discharge of 1,000 t/s and a water level of 4.7 m. This is a section that closes depending on the dam’s discharge and water level.

The 3 rows of Prefectural Road 338, the Iwagi-Yuge Line (Yuge Bridge, Ikina Bridge and Iwagi Bridge), have no rainfall standard and show wind speeds of 15 m/s for motorcycles and 25 m/s for vehicles, and freezing. For these 3 rows, the standards are wind and freezing, not rain.

Of the roads covered in other articles, these 2 relate to the prefecture’s table.

The road to the foot of Mt. Ishizuchi: The Saijo side of Prefectural Road 12 (Nakano Bridge to Omiya Bridge, 20.7 km) is in the table.
The road to Shimonada Station: For National Route 378, the rows for Yawatahama, Seiyo and Suzawa in Nagahama, Ozu, are in the table, and no row in Iyo is listed.

22 Special Restriction Sections

The second kind, special restriction sections, has no rainfall standard. The prefecture’s page says this.

気象・現地の状況等を判断して危険が予想される場合に通行規制します。

Translation: “Traffic is restricted when danger is expected after judging the weather and conditions on site.”

The list has National Route 197 (Oku (大久) to Natori (名取), Ikata Town, 3.7 km), National Route 378 (Anai, Yawatahama; Shuki, Mikame, Seiyo), National Route 441, and 18 prefectural road sections. Prefectural Road 256, the Sadamisaki-Misaki Line (Nosaka to Sadamisaki, Ikata Town, 3.0 km), which goes to the lighthouse at Sadamisaki, is also here. This road is covered in the article on Misaki Port to Sadamisaki Lighthouse.

Because no rainfall figure is given, you cannot estimate in advance from a standard. On days of heavy rain or typhoon, check on the day whether a restriction is in force.

National Roads Managed by the National Government: Continuous Rainfall Set by the Matsuyama River and National Highway Office

National Routes 11, 33, 56, 192 and 196 are managed directly by the Ministry of Land, Infrastructure, Transport and Tourism. Of Routes 11 and 33 managed by the Matsuyama Daiichi National Highway Maintenance Branch of the Matsuyama River and National Highway Office, the sections closed because of rain are as follows.

Route	Restriction section	Length	Restriction condition
National Route 11	Saijo (Tanbara, Shikawa) to Toon (Kawanouchi): 西条市丹原町大字志川～東温市大字河之内	5.8km	Continuous rainfall 300mm
National Route 33	Kumakogen (Nakatsu, prefectural border) to Yanaigawa: 久万高原町中津（県境）～柳井川	6.1km	Continuous rainfall 250mm
National Route 33	Kumakogen (Yanaigawa to Nakakuroiwa): 久万高原町柳井川～中黒岩	7.6km	Continuous rainfall 250mm
National Route 33	Matsuyama (Kubono-cho) to Tobe (Sensoku): 松山市窪野町～砥部町大字千足	12.9km	Continuous rainfall 250mm

Source: 松山河川国道事務所/事務所紹介/出張所紹介/道の管理について (checked on October 13, 2026). The table is the “advance traffic restriction map” on the “About road management” page of the Matsuyama River and National Highway Office. The names “Ehime Prefecture,” “Kamiukena District” and “Iyo District” are left out of the section names.

For National Route 33 on the Matsuyama Side, Two Pages Say Different Things

On the National Route 33 page of the MLIT road information system, the row for the Matsuyama side is written differently.

Section	Restriction condition
Matsuyama (Kutani-cho) to Tobe (Sensoku): 松山市久谷町～砥部町千足	Continuous rainfall 300mm, or continuous rainfall 170mm and hourly rainfall 50mm

The office’s page gives “Kubono-cho, Matsuyama, to Sensoku, Tobe” as 250 mm of continuous rainfall, and the system’s page gives “Kutani-cho, Matsuyama, to Sensoku, Tobe” the condition above. The starting place name of the section and the standard are both different. Neither page shows an update date, and it could not be confirmed which is current. The current standard on the Matsuyama side has not been confirmed. For the 2 sections in Kumakogen Town (Nakatsu to Yanaigawa, Yanaigawa to Nakakuroiwa), both pages agree on 250 mm of continuous rainfall.

For the rows of National Route 33 in Kumakogen Town, the road information system page gives the reason as “連続雨量250mm　又はパトロールにより危険と思われる時” (continuous rainfall of 250 mm, or when patrol judges it dangerous). Even if the standard is not reached, a road may close if a patrol judges it dangerous. The advance-closure information page of the Shikoku Regional Development Bureau also has an explanation to the same effect.

(2) 連続雨量が規制基準雨量に達しない場合でも、パトロールにより危険と判断される場合は、通行止めとなる場合があります。

Translation: “(2) Even when continuous rainfall does not reach the restriction standard rainfall, the road may be closed if it is judged dangerous by patrol.”

Even After the Rain Stops, Reopening Is Late

The Matsuyama River and National Highway Office writes the steps for reopening like this.

雨が止んで2時間後に通行規制区間内をパトロールし、安全が確認され、さらにその後の気象条件等を考慮したうえで通行規制を解除します。ただし、夜間の場合は十分な安全確認が出来ないため、夜明けを待ってからパトロールを行います。

Translation: “Two hours after the rain stops, a patrol is made within the restricted section, and after safety is confirmed and later weather conditions are also considered, the traffic restriction is lifted. However, at night, sufficient safety confirmation cannot be done, so the patrol is made after waiting for daybreak.”

If the rain stops at night, the restriction is lifted the next morning or later. Even if you see the rain stop in the evening and set out, the road is not always open.

National Routes 56, 192 and 196

The National Route 56 page of the Shikoku Regional Development Bureau system lists 4 rows in Ehime (Takagushi (高串), Uwajima, to Tachimajiri (立間尻), Yoshida; Tachima (立間), Yoshida, to Igaue (伊賀上), Uwa; Shinzato (信里), Uwa, to Kitatada (北只), Ozu; Nakayama-cho (中山町), Iyo, to Ohira (大平)). The National Route 192 page has a row from Shimoyama, Kawataki-cho, Shikokuchuo, to Hakuchi, Ikeda-cho, Miyoshi City, Tokushima Prefecture. The continuous rainfall column is “-” in all of them, and the reason column says only “preventive traffic restriction section” (予防的通行規制区間).

The Matsuyama River and National Highway Office page explains preventive traffic restriction sections as sections for heavy snow.

大雪時に大規模な立ち往生が発生するおそれがある山間部の峠などの区間を「予防的通行規制区間」として指定しています。

Translation: “Sections such as mountain passes where large-scale stranding may occur in heavy snow are designated as ‘preventive traffic restriction sections.’”

Because they are not rain standards, they are not in the rain tables of this article. National Route 196 was not in the route list of the road information system. Whether these 3 routes have advance traffic restrictions based on rainfall has not been confirmed.

Expressway Rain: The Matsuyama Expressway and the Imabari-Komatsu Expressway

NEXCO West Japan says that closures for rain, earthquakes and strong wind are made at standard values set for each section.

降雨・地震・強風（異常気象等）により災害が発生するおそれがあるため、区間毎にあらかじめ設定した規制基準値に達した時点で通行止めを実施します。

Translation: “Because disasters may occur due to rainfall, earthquakes and strong wind (abnormal weather and the like), a closure is carried out when the restriction standard value set in advance for each section is reached.”

The standard values are published in the PDF “Advance traffic restriction standards for abnormal weather and the like” (as of August 14, 2026; written as “R8.8.14” in the PDF). The rows in Ehime are as follows.

Road	Section	Continuous rainfall	Combined rainfall (continuous rainfall and hourly rainfall)
Matsuyama Expressway	Kawanoe JCT – Doi IC	350mm	250mm and 40mm
Matsuyama Expressway	Doi IC – Iyo-Saijo IC	350mm	270mm and 40mm
Matsuyama Expressway	Iyo-Saijo IC – Kawauchi IC	300mm	250mm and 40mm
Matsuyama Expressway	Kawauchi IC – Matsuyama IC	“－” (no rainfall standard value written)	“－”
Matsuyama Expressway	Matsuyama IC – Iyo IC	200mm	180mm and 40mm
Matsuyama Expressway	Iyo IC – Uchiko-Ikazaki IC	160mm	140mm and 40mm
Matsuyama Expressway	Uchiko-Ikazaki IC – Ozu IC	190mm	140mm and 40mm
Matsuyama Expressway	Ozu-Kitatada IC – Seiyo-Uwa IC	180mm	130mm and 40mm
Imabari-Komatsu Expressway	Iyo-Komatsu JCT – Imabari-Yunoura IC	300mm	250mm and 40mm

Source: 異常気象等による事前通行規制基準 (NEXCO West Japan; as of August 14, 2026, written as “R8.8.14”). The entry ramp toward Takamatsu at Iyo-Komatsu JCT (continuous rainfall 200mm, combined rainfall 160mm and 25mm) in the PDF is left out. The PDF calls the route the Imabari-Komatsu Road (今治小松道路).

The PDF notes explain continuous rainfall and combined rainfall like this.

（注１）　連続雨量とは、雨の降り始めから降り終わりまで2mm/ｈを超える雨が6時間以上の中断を伴わず継続した場合の累積雨量をいう

Translation: “(Note 1) Continuous rainfall means the accumulated rainfall when rain exceeding 2 mm/h continues from the start of the rain to the end without a break of 6 hours or more.”

（注２）　組合せ雨量とは、連続雨量とその時点における時間雨量の組合せで定められる雨量をいう

Translation: “(Note 2) Combined rainfall means the rainfall set by a combination of continuous rainfall and the hourly rainfall at that time.”

For example, between Matsuyama IC and Iyo IC, besides when continuous rainfall reaches 200 mm, it also meets the closure standard when continuous rainfall exceeds 180 mm and hourly rainfall reaches 40 mm or more.

The row for Iyo IC to Uchiko-Ikazaki IC has a “※” mark. According to the PDF note, this is a section where emergency repairs were made after past slope disasters, and a provisional standard value lower than usual is set. The lowest continuous rainfall that appears in the table for the Matsuyama Expressway, 160 mm, is this section.

The row for Ozu IC to Ozu-Kitatada IC is not in the table. The standard for this section could not be confirmed.

Reopening After the Rain Stops

NEXCO West Japan gives this reason why it cannot announce the reopening time in advance.

地震・雨・強風・雪・霧等の異常気象に伴う通行止めの場合は、天候が安定した後においても風倒木の除去作業や除雪作業に加え、道路が安全に走行できる状態になっているかといった確認を、警察機関と弊社双方で行う必要があり、弊社だけの判断で解除できるものではございませんので、あらかじめ、解除予定時間といったものをお知らせすることはできません。

Translation: “In the case of a closure due to abnormal weather such as earthquakes, rain, strong wind, snow and fog, even after the weather has settled, in addition to removing fallen trees and snow, both the police and our company need to check whether the road is in a condition where it can be driven safely, and we cannot lift the closure on our company’s judgment alone, so we cannot announce a planned reopening time in advance.”

If heavy rain falls on a day you go from Matsuyama Airport to Nanyo or Toyo by expressway, plan your schedule on the assumption that the reopening time cannot be known. The road to Nanyo by the Matsuyama Expressway is in the article on Matsuyama Airport to Uwajima Castle.

Expressway Wind: NEXCO West Japan Uses an Average Wind Speed of 20 m/s Over 10 Minutes as a Guide

For wind, the notes of the NEXCO West Japan PDF have this.

強風については、10分間の平均風速が20m/s以上を目安とし、継続または継続が予想され、必要と認められる場合に通行止めを実施する

Translation: “For strong wind, an average wind speed of 20 m/s or more over 10 minutes is used as a guide, and a closure is carried out when it continues or is expected to continue and is judged necessary.”

This is a guide for the routes that NEXCO West Japan manages. The Shimanami Kaido (Nishiseto Expressway) is run by a different company, as the next section explains.

The Shimanami Kaido: Wind and Rain Rules of JB Honshi Expressway

The Shimanami Kaido is managed by Honshu-Shikoku Bridge Expressway Company (JB Honshi Expressway). The JB Honshi Expressway page “Requests for Traffic Safety” says this about wind on the bridges.

海峡部の橋上では、思いもしない突風や横風が吹くことがあります。

Translation: “On the bridges over the straits, unexpected gusts and crosswinds may blow.”

It then gives its policy on closures like this.

本四高速では、強風が予想される場合、早めに全車通行止めを実施しています。

Translation: “When strong wind is expected, JB Honshi Expressway closes the road to all vehicles early.”

Wind speed figures were not found on the JB Honshi Expressway pages. This article cannot say at what m/s the road closes.

Sometimes Only Motorcycles Are Stopped

The JB Honshi Expressway closure information page says this about motorcycles.

本四高速道路は、風速によって、四輪車が通行止めにならなくても、二輪車は通行止めになることがあります。現在の道路状況をご確認ください。

Translation: “Depending on wind speed on the Honshu-Shikoku expressways, motorcycles may be closed to traffic even if four-wheeled vehicles are not. Please check the current road conditions.”

The motorcycle closure information page has a column for the Nishiseto Expressway. The same company’s “Requests for Traffic Safety” page names the Akashi Kaikyo Bridge, the Ohnaruto Bridge and the Seto-Ohashi Bridge as the objects of motorcycle-only closures, and does not name the bridges of the Shimanami Kaido. On days you ride a motorcycle on the Shimanami Kaido, look at the closure information page.

In the Heavy Rain of June 2026, Closures Occurred on the Nishiseto Expressway

The JB Honshi Expressway page “Information related to closures due to abnormal weather and the like” lists notices of past closures. For the heavy rain of June 24 to 26, 2026, the notice as of 14:50 on June 25 has this.

大雨の影響により、E76 西瀬戸自動車道で通行止めの区間があります。

Translation: “Because of the heavy rain, there are sections of the E76 Nishiseto Expressway that are closed to traffic.”

The same notice says that the section from Innoshima-minami IC to Oshima-minami IC was reopened at 14:50. In the notices for the strong wind of May 1, 2026 and Typhoon No. 6 on June 2, the only route closed was the Seto-Chuo Expressway, and the Nishiseto Expressway was not included. The range of closure differs with each event, for wind and for rain, so the example here is a single case, the heavy rain of June 2026.

Ordinary Roads for Detours

The closure information page has this note about ordinary roads on the islands.

※E28 神戸淡路鳴門自動車道における淡路島内及びE76 西瀬戸自動車道（しまなみ海道）の島内で一般道が並行する区間では迂回が可能です。なお、一般道も通行規制が実施されている場合がありますので、あわせてご確認ください。

Translation: “* A detour is possible in sections where an ordinary road runs in parallel, on Awaji Island on the E28 Kobe-Awaji-Naruto Expressway and on the islands on the E76 Nishiseto Expressway (Shimanami Kaido). Traffic restrictions may also be in force on ordinary roads, so please check them as well.”

Restrictions can also apply to ordinary roads. In the prefecture’s table, the 3 bridges of Prefectural Road 338 in Kamijima Town (Yuge Bridge, Ikina Bridge and Iwagi Bridge) have wind speed standards (15 m/s for motorcycles, 25 m/s for vehicles). They are not standards for the main line of the Shimanami Kaido.

The road to Omishima by the Shimanami Kaido is in the article on Matsuyama Airport to Oyamazumi Shrine.

Pages and Phone Numbers to Use During a Trip

On a day when a heavy rain or typhoon forecast is out, look at these pages before you leave and at your lodging or rest stops. Do not look at the screen while driving. Have a passenger check, or stop the car and check.

What you want to know	Where to look	Phone
Traffic restrictions on prefectural and national roads	From the Ehime Prefecture page “Links on Ehime road information” (愛媛県道路情報に関するリンク), go to the MLIT road information system (Ehime traffic restriction information)	Ehime Prefecture Road Maintenance Division 089-912-2720
National Routes 11, 33, 56 (Chuyo), 192 and 196	MLIT road information system	Matsuyama River and National Highway Office 089-972-0034
National Route 56 (Nanyo)	Same as above	Ozu River and National Highway Office 0893-24-5185
Road surface conditions	Ehime Road Live Cameras (えひめの道ライブカメラ) (the Ehime Prefecture page says road conditions at 55 places in the prefecture can be seen)
Expressways in Shikoku such as the Matsuyama Expressway	NEXCO West Japan traffic information, i-Highway	NEXCO West Japan Customer Center 0120-924-863
Shimanami Kaido	JB Honshi Expressway closure information, motorcycle closure information	Shimanami Imabari Management Center 0898-23-7250
Road information in Ehime Prefecture	Japan Road Traffic Information Center	050-3369-6638

The phone numbers are the ones on the Ehime Prefecture page “Links on road information.” The overall picture of where to look for road information is summarized in Where to Check Ehime Road Information Before You Leave. Winter closures and the winter tire rules are in Before Driving Ehime’s Mountain Roads in Winter.

The Matsuyama River and National Highway Office writes this about going out in heavy rain.

豪雨などの異常気象時には、不要不急の外出や移動はおやめください。

Translation: “During abnormal weather such as heavy rain, please refrain from non-essential and non-urgent outings and travel.”

What Could Not Be Checked This Time

At what wind speed in m/s the Shimanami Kaido closes. The JB Honshi Expressway pages had no figure.
The current standard for National Route 33 on the Matsuyama side (Kubono-cho to Sensoku, Kutani-cho to Sensoku). The 2 national pages differ.
Whether National Routes 56, 192 and 196 have advance traffic restrictions that close the road by rainfall.
The rainfall standard for the Matsuyama Expressway between Ozu IC and Ozu-Kitatada IC. There is no row in the NEXCO West Japan table.
The unit of the rainfall columns in the Ehime Prefecture table. It is read as mm from the Ishizuchi Skyline page for Prefectural Road 12.
How long a closure lasts when a restriction is applied, and how long the detour takes.

About This Article

The pages listed here were opened and checked on October 13, 2026. The update date of the prefecture’s page is March 2, 2026, and the NEXCO West Japan standards are as of August 14, 2026. The 2 MLIT pages show no update date. Standards and sections may change. Please follow the signs on site and the guidance of the road managers on the day.