A brilliant piece of planning

[ARWadsworth]

[The Natural Philosopher]

Like er if we had anywun of enny intellgence we could like er look at the photothings eeven wivout an Ipad and that and work it out sinetifickly, but no one can do sinenc ennymore since the sinenc marster got blown up in a trrist attak

[js.b1]

A brilliant piece of planning in Switzerland in the tunnel.

- Emergency lane tarmac has no rumble bars.

- Solid concrete square-on wall at the end & attached to a mountain.

- Relatively poor lighting re dark-to-light adaptation.

- Concrete wall is painted green which is one of the worst colours in poor light with a "horizon" formed by not painting the top part, so creating the illusion of a dark road with light concrete tunnel above. Why not bright freakin dayglo orange?

- The solid square-on wall has no light reflectors on it.

- The square-on wall has no crush barrier, like 5ft of aluminium honeycomb crush (or even 10ft of coca-cola cans).

Ok, perhaps the bus snagged a kerb pulling the wheel, or a lorry moved into its lane pushing it over.

Whatever.

There should have been a crush barrier like UK Highway's Agency have on the back of trucks. Over-rider design to prevent a side-slip into the other lane, and big enough to absorb a head-on from a 89,000lb truck. Alternatively a crash barrier to deflect as the UK does around motorway concrete pylons (having found a loaded tanker had enough kinetic energy to shear the mounting to the top overpass creating the risk of a much larger secondary road accident).

[ARWadsworth]

That was the second route for Diana.

[js.b1]

Did wonder how tunnels affected the wireless trigger of the Carbon Monoxide cylinder :-)

[John Williamson]

There *is* no emergency lane, just refuges. There is a raised curb about two feet out from the tunnel wall.

go to:-

use street view to enter the tunnel and see what the driver would have seen.

Irrelevant in this case, as it happened after dark.

During the day, the first part of the tunnel is brightly lit, then it gets darker as you go further in, and finally the level of lighting increases as you approach the exit.

Possibly because dayglo orange is the colour of choice there for hi-visibility vests, and they stand out better against green walls. I have had no problems at all drivng through these tunnels.

It's also a pretty good simulation of driving along a road lined with tall hedges in daylight.

As it is recessed from the tunnel wall, why would it need them?

Okay, who's going to pay for the extra holes? To safely slow the coach down, it would have needed about 20 metres of crush barrier, not five feet, and even that would have been marginal. You're proposing fitting this to many thousands of safety refuges at a (guesstimated) cost of at least half a milion Swiss Francs each.

Or the driver had a heart attack, or... We don't know what happened, and I'm not going to go knocking on the Pearly gates to find out. That's the only way to interview any reliable witnesses in this case, unfortunately.

The only vaguely sensible suggestion in that lot is the deflector, and you've got to balance the many smaller accidents that it would no doubt cause by deflecting out of control vehicles back into the traffic lanes, after they had diverged slightly from the correct line.

In many journeys through tunnels of this and similar designs in Switzerland and other countries, I've never noticed even a scratch on the tunnel walls. It's a pretty safe design, on the whole.

[ts]

[js.b1]

Not irrelevant, there is often a marked difference in lighting outside tunnels compared to inside.

It is well known that vehicles drift onto hard shoulders & refuge lanes. Any vehicle swerving or drifting into the refuge lane is presented with a square-on-wall.

The hard shoulder is the most dangerous part of a UK motorway, it is why the Highways Agency has bright orange trucks, bright orange lights and indicating directional arrows.

At the minimum it should have had light reflectors on the wall and angled road markings on the road, rumble strips would have been a cheap simple solution.

Rubbish. The Highways Agency uses a hinge-down honeycomb aluminium structure on the rear of vehicles to diminish impact from a UK lorry. It would need nothing like 20 metres, reducing final impact speed with the wall to

30mph would provide a reasonably survival impact for a coach load of people (dozens passengers & 1 driver) - but not a lorry (1 driver, perhaps a passenger).

Quite possibly. There should be CCTV coverage of the tunnel, but it may not cover the relevant area.

Deflectors are pretty standard, but a coach is difficult if the refuge lane is relatively short.

Going by the history of fires in swiss & similar tunnels, not.

Yes they are few per vehicle kilometres, per year etc, but there can be substantial loss of life when there is a crash.

[Tim Streater]

While Swiss roads etc are well constructed, they are poorly designed IME. I agree that retro-fitting that tunnel would be expensive, but that is just the point.

When I was first at CERN in the late 60s, the road from Geneva to CERN, past the end of the main runway of the Airport, was one lane in each direction. They gradually widened this to two lanes in each direction , almost all the way. So far so good. But then some bureaucrats must have got hold of it - they added turnoffs, slip roads, bits you can't drive on, etc, so much so that by the time I left CERN beginning of the 80s, in effect that road was ... back to one lane each way.

As I was leaving the area, they were finishing an underpass on a sort of bypass road, used by trucks from northern Europe around Geneva and on to Lyon. Again, a lot of huffing and puffing - producing one lane each way.

[Tim Streater]

Quite. What they should have done, when building it, was to taper off the wall at the end of the lay-by, so that any vehicle (like this bus) would have just scraped off the wall. And rumble strips off diminishing width to indicate that the klod should Get in Lane.

[Nightjar]

Difficult to tell whether that is true or not. There are lots of markings that could incorporate them.

Because dayglo orange is not the international colour for an emergency exit, whereas green is.

They would normally be on the Armco (see below)

The Google earth view inside the tunnel shows a single height Armco barrier that presumably was intended to provide some protection. The bus seems to have climbed over it, which is not unusual for large vehicles. Double height Armco is normally required to stop a lorry or bus.

Colin Bignell

[djc]

A refuge is not a 'hard shoulder'

On the rear of a vehicle, if hit the vehicle would move. Mountains do not.

It would need

A fire is not an impact.

[Nightjar]

That shows a refuge that slowly diverges from the main lane, before coming to an abrupt halt in a wall at right angles to the direction of travel. The deceleration lane is well marked on the road with diagonal lines, but someone following the line of the tunnel wall would hit the Armco barrier just before the end wall. Looking at its position before being removed, I would say that the bus probably climbed over that.

...

Simply building the end wall at, say, 45 degrees to the direction of travel would have had the same effect as a deflector.

I can't say I've ever found the time to study the tunnel walls in that much detail at motorway speeds.

Colin Bignell

[John Williamson]

That's the standard design. There are thousands of them in Switzerland.

The trick is that half the time, it's not me driving. ;-)

We always run those jobs with two drivers.

[js.b1]

No, it is worse, because whilst completely open to traffic it results in a square-on wall.

Coach about 45ft long, survivors in rear 22ft. To achieve a reasonable reduction in deaths the crumple zone would need to be equivalent to 12ft of coach. Not difficult for a honeycomb structure to achieve that in less than

12ft. However, it is very expensive with too many refuge to protect through Switzerland. So risk assessment fits to the 2 refuge on entering a tunnel where a driver's cognitive load is high or familiarity breeds a simple mistake (most accidents happen near home etc).

Cheapest is turning square-on concrete to a deflection-on concrete. So making the refuge sections of tunnel no worse than the rest.

Deflection barriers need care in tunnels, even K-barriers with backing interlocked blocks need space to traverse, because vehicle tilt can result in the roof line passing behind the roof line and hitting immovable concrete structures (or projections).

Cheapest is change the square-on concrete on the entry refuge's to the tunnel.

[Nightjar]

Being Swiss, the authorities probably don't expect anyone to drive into the lane unless they are planning to stop at the emergency phone. There are, after all, rules to follow.

Colin Bignell