Failure Knowledge Database / 100 Selected Cases

The fire disaster in the Tokyo-Nagoya Nihon-zaka tunnel
July 11th 1979

Shizuoka Prefecture

Masahiko Kunishima・Kenichi Horikawa（*１）
On July 11th 1979, at around 18:40, on theline (bound for Nagoya) of theTokyo-Nagoya highway, a fire disaster occurred in Nihon-zaka tunnel at a location
400m from the exit of the tunnel as a result of a collision between four big trucks andtwo small passenger cars, and the fire expanded to the cars behind. Due to this disaster,seven persons died as their cars burned, two persons were injured, and 173 cars caught
fire. Furthermore, damage of the tunnel itself and of the equipment for fire
extinguishing had occurred. Finally, the disaster caused the major transportationartery connecting Tokyo and Nagoya to be shut down temporally, resulting in a major
confusion of the regional transportation network.
１．EventAt around 18:40 July 11th 1979, on the Nagoya-bound line of the Tokyo-Nagoya
Highway, in the 2045m long Nihonzaka-Tunnel at a location 400m from the Yaizu-side
exit, a large truck with an Osaka license plate number collided with a large truck with aNagoya number from behind.

The passenger cars behind the truck and another large

truck also collided with the first two trucks. It was thought that a fire had broken out
from one of the passenger cars, and that the fire first expanded to all five trucks andcars, filling the inside of the tunnel with black smoke.
The driver of the car behind the location of the accident put his car into reverse andmade a space of at least 70m from the fire, but the fire expanded and engulfed thefollowing cars including his car.

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Failure Knowledge Database / 100 Selected Cases

Figure１：The location of Nihon-zaka（日本坂） tunnel

Figure 2

The location of Nihon-zaka tunnel（Source: Highway and car. The researchcommunity of highways, Nihon-zaka tunnel’s fire disaster and its aid actions.）
２．Course
In the truck and cars that collided and caused the fire, there were three passenger car

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Failure Knowledge Database / 100 Selected Cases

drivers and one truck driver. The drivers of the other cars tried to rescue them, but it
was impossible because of the fire and smoke. So they walked to the Nihon-zaka
parking area 3km from the place of the accident and informed the officials there of theaccident.
３．CauseThe second large truck (B) ( please see Figure 1) collided with the first truck (A) frombehind, and the following two passenger cars (C) and (D) collided with the truck (B) one
by one. Next, the sixth vehicle, truck (F), collided with the fifth vehicle, passenger car(D), at a speed of about 100km. Because of these circumstances, the passenger cars werecrushed between the trucks, then a crack was made on the gasoline tank, and the fireand explosion occurred due to an electric circuit short.
The cause of the first collision was the sudden braking of truck (A), due to the latenessof the traffic jam. The truck stopped just touching a van and a truck located in front of it.
The traffic jam was caused by a small accident where two trucks had collided close tothe Yaizu-exit. These two trucks were quickly moved away, but not before a traffic jam
was generated around the exit. Truck (A) braked suddenly 100m away from this trafficjam, and the following truck (B) collided with truck (A) from behind. In addition, before
this accident, a traffic accident had occurred in this tunnel close to the Shizuoka-side.
After the occurrence of the accident close to the Yaizu side, the alert on the entrance wasactivated, but about 80 cars and trucks still entered into the tunnel after that activation.
Actions in a highway accident occur on the scale of minutes and seconds.
Please look at Picture 1 showing the condition of the disaster location after the fire.
Yaizu-side exit

Shizuoka-side exit

Direction of trafficLarge truck（Ａ） passenger car （Ｃ） Large truck (plastic)（Ｅ）
Large truck（Iron 10t）（Ｂ） Passenger car（Ｄ） Large truck（plant oil）（Ｆ）
Figure 3 Sketch of the location of the disaster (Source: Fire disaster Japanese academyof fire disaster “The fire disaster of Nihon-zaka tunnel)

3Failure Knowledge Database / 100 Selected Cases

Picture１ The condition 1240ｍ from the Shizuoka-side Exit (Source: Highway and car.
The research community of highways, Nihon-zaka tunnel’s fire disaster and itsaid actions)
４．Immediate Action
This accident occurred in a tunnel that was equipped with a disaster-prevention facilityof rank A. The actions of the administration offices related to this accident were asfollows.
18:39 the vehicle accident was recognized.
18:39 From the emergency call in the tunnel to the Control office in Kawasaki,
information was made available that a fire accident from a vehicle collision hadoccurred. The information was passed on to the fire fighting department ofShizuoka. At the same time, the control room of Shizuoka also recognized theaccident from the alert bell and it observed the fire on the ITV system due to thefire occurrence alert. Each of the fire prevention facilities were operated in thefollowing order; display of the "Do not enter" alert on the alert board of the tunnel
entrance, activation of the sprinklers as well as all of the lights and ventilation
fans.
Around 19:05 A malfunction of the ITV and the lights was shown in the controlroom.

After this time, only the ventilation fan for escaping was working. All otherfacilities, including lights and fire extinguishers, were not functioning because the4Failure Knowledge Database / 100 Selected Casescables were burnt; the fuses were blown out and so on.
Around 19:45 The pump was restarted by hand in the east ventilation tower.
Around 19:50 The patrol car arrived at the site of the accident and started to leadthe evacuation.
Around 20:05 The 170t of water in the main tank was exhausted.
Around 21:30 208 passenger car drivers in the tunnel were rescued and moved into
the Shizuoka control office.
５．Countermeasure
From July 14th, the investigation of the accident was started, and improvementsof the fire extinguishing facilities and the regulations inside the tunnel were begun.
These operations were completed around August 8th to September 5th. For theelectric circuits of a quarter of the lights, the escape leading lights and thesprinklers, fire-proof cables were installed. This measure was not required by theregulations at that time, but was installed as a drastic measure in this case. *10
water taps for extinguishing fires were installed for every 200m of the tunnel.
Before this accident, these were installed only on the entrance and exit.
*Self-powered exit lights that can shine for 30 minutes after a loss of power were
installed in three places, and escape leading lights were installed in eight places.
*Two alert boards (one is 700m ahead of entrance, the other is at entrance ) wereinstalled. According to the regulations, one alert board 200m ahead of the entrance
was enough. *The speed limit in the tunnel was fixed at 70km/h. *Lane changes inthe tunnel were made illegal. *Distance confirmation sign and it on the road weremade. *For the alert, thin pavement on the entrance were made.
６．Sequel
Repair costs paid for this tunnel disaster and the costs for the improvement of thedisaster prevention equipment are totally 3.4 billion yen. And profit reduced by thesuspension of traffic caused by this accident was estimated 3.3 billion yen. If we could
prevent the disaster by effective disaster prevention equipment, as the result, theinvestment would become the effect of plus.
７．Knowledge
This vehicle accident would not have occurred, or at least would have been muchsmaller, if the trucks and cars had maintained space between the vehicles and if theother cars had obeyed the alert on the tunnel entrance. Considering that there are a lot5

Failure Knowledge Database / 100 Selected Casesof trucks that contain dangerous and inflammable materials, the ability to prevent all
accidents by improving the fire prevention facilities is limited. In fact, this accident had
occurred in a tunnel with a ranked fire prevention facilities. In addition to the hardware
side of fire prevention, the software side of it, such as increasing the sense of caution of
the drivers, is also important.
（*１）Graduate school of Frontier science, the University of Tokyo＜Reference＞
Nihon-zaka tunnel disaster and its civil responsibilities.
Kazurou Kunii, Jurist Yuuhikaku １９７９．１０
Nihon-zaka tunnel’s fire disaster and its aid actions
The research community of highways. Highway and car. １９７９．１２
Repair of the Nihon-zaka tunnel
Toshitaka Samezima, Kimiaki Akai, Norio Yamada
Japan society of civil engineering １９８０．０４
Lesson from the Nihon-zaka tunnel disaster
Motokazu Hoshi Highway and car The research community of highways
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