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NEXCO EAST Niigata Regional Head Office (Niigata Chuo-ku) is, E8 Hokuriku Expressway between Oyashirazu wisdom tooth IC from Asahi Asahi Interchange (IC), it will be carried out renovation work of the tunnel.
The work to be carried out this time is an invert installation work to prevent the board blistering of the Shiroyama Shiroyama tunnel (Out-bound
During the construction period, the upper and lower lines will be consolidated on In-bound line (toward Toyama), and face-to-face traffic will be restricted throughout the day, with one lane on each side. It is predicted that there will be no traffic congestion due to construction work.
In addition, when switching to face-to-face traffic restrictions throughout the day, we will close night traffic on June 1 (Tuesday), so please detour to National Highway No. 8.
We apologize for the inconvenience caused to our customers, but during the construction, the number of lanes that can be driven will be reduced from 2 lanes to 1 lane. Please.
Renewal work is necessary to use the Expressway We will do our best to minimize the inconvenience to our customers, so we ask for your understanding and cooperation.

1. Construction overview

2. Restricted sections and detours

Hokuriku Expressway Asahi IC-Etchusakai PA, maximum of about 4.5km will be regulated.

When closing, please make a detour to general national highway No. 8.

<Time required>

	Expressway use	Use of National Highway 8
Asahi IC-Clairless IC	About 14 minutes	About 23 minutes

3. 3. Regulation period

Four. Outline of construction regulations

For tunnel invert construction, the section of 2 lanes on each of the upper and lower lanes will be reduced to 1 lane each In-bound line side, and face-to-face traffic restrictions will be enforced throughout the day.
During the one day before the start of the two-way traffic regulation (Tuesday, June 1st), the upper and lower lines will be closed at night to switch lanes to the two-way traffic regulation. In addition, at the end of the two-way traffic regulation, we will close the upper and lower lines at night for the work of switching to the day and night continuous lane regulation for one night (Friday, October 29 (scheduled)).

■ All-day face-to-face traffic restrictions (June 2nd to October 29th)

Five. Request when using

1. The construction section will be subject to face-to-face traffic restrictions of approximately 4.5km throughout the day. Since the number of lanes will be reduced from the current two lanes on each side to one lane, please make efforts for safer driving and go out with plenty of time.
2. Since the lane width is narrow in the two-way traffic restricted section, please observe the regulated speed when driving, secure the inter-vehicle distance, and be careful about rear-end collisions. In addition, the lanes will change significantly before and after the two-way traffic regulation section, so please follow the local information signs.
3. Vehicles for construction work may enter and leave the area around the construction site, so please be careful when traveling ahead.
4. During the construction period, we will provide construction regulation information using road information boards and road signs and call for caution to drive safely. Before riding, please check the above information before riding safely.
5. ​Please refer to Attachment-2 [PDF: 232KB] for the adjustment of the transfer fare due to the closure of the night traffic section (Asahi IC-Oyashirazu IC). We will not adjust the transfer fare due to the detour of the two-way traffic restricted section (Asahi IC-Etsuchukai PA).

6. Overview of invert installation work

Invert construction is Expressway renewal project, and by installing an invert, the tunnel is closed to increase the yield strength, prevent deformation such as uplift and subsidence, and improve stability.

State of invert installation work (example of Out-bound

Expressway renewal project

More information on the Expressway renewal project