Great Western Coffee Shop

Except the Lorry in the picture is not the offender. That was a lorry carrying an excavator. That will be a very expensive insurance claim.  I think the driver may well have some explaining to do to Kent police as well. 

No warning signs of a height restriction that I can see on street view.

The truck with excavator was in the hard shoulder.

Is it one of these smart motorways allowing hard shoulder running?

I drive down that stretch of the M20 a fair amount and there is no smart motorway system there so if someone was  on the hard shoulder they should have been treating it as such. It does look like it happened just before the M26 turn off but again no reason for someone to have been in the hard shoulder really unless they had an issue with their vehicle.

The bbc reported it was being driven on the hard shoulder.

Is it a fairly new foot bridge? looked to have construction fencing on it

...
No warning sign is required if the height of the bridge is over (IIRC) 5.5m (16ft 6in).
...

A.3 Unsigned bridges with 16’-6” (5.03m) or more headroom
A.3.1. Bridge deck is designed or has been assessed as able to resist vehicle impact forces,
current at the time of the surfacing works, as advised/agreed by the bridge owner:
(a) if existing headroom is 16’-6” (5.03m) or more allow reduction to 16’-9” if sought.
(b) if existing headroom is between 16’-9” (5.1m) and 16’-6” (5.03m) then no reduction
is allowed and efforts should be made to increase it to 16’-9”.
A.3.2 Lightweight structures not capable of resisting current impact forces as advised/
agreed by the bridge owner:
(a) if existing headroom is greater than 17’-9” (5.41m) allow reduction to 17’-9” if sought.
(b) if existing headroom is between 17’-9” (5.41m) and 16’-6” (5.03m) then no reduction
is allowed and efforts should be made to increase it to 17’-9” or as high as possible
and at least to 16’-9” if lower than this.
A.3.3 Relevance of different clearances:
A.3.3.1 Chapter 6 of TD 27/05* specifies headrooms, including additional provision for
sag curve compensation (S), for new construction and maintenance as follows:

• 16'-6” (5.03m) + S is the standard minimum maintained headroom below which all
  bridges should be signed.
• 17'-5” (5.30m) + S is the standard design headroom over the accessible highway
  for new bridges designed to resist current impact forces and for those built since
  the earlier version of TD 27 came into force in 1996.
  
• 18'-9” (5.7m) + S is the standard design headroom over the accessible highway
  for new lightweight structures, ie, those not designed to resist impact forces, and
  for those built since the earlier version of TD 27 came into force in 1996.
  
• 17'-9'’ (5.41m) + S is the equivalent minimum maintained headroom for new
  lightweight structures and those built since the earlier version of TD 27 came
  into force in 1996.
  
• Design headroom is provided for structures at construction and allows for
  subsequent limited surfacing overlays for maintaining the highway beneath.
  
• Maintained headroom is that minimum which must not be reduced at any time
  and which will consequently determine, along with other local issues, the
  possibility of overlaying.
  

A.3.3.2 The CSS suggests that highway authorities should over time aim to make 16'-9”
(5.10m) the minimum maintained headroom for all bridges prior to signing due to
confusion in drivers’ minds that 16’-6” (5.03m) represents the safe vehicle height for
unsigned bridges rather than the actual minimum headroom.

- and not just because 5.5 m isn't 16'6".

I'm pretty sure TD 27/05 is no longer in force, having been replaced by something or other, though I imagine its content is still valid.

*TD 27/05 is: ‘Cross Sections and Headrooms’ in DMRB Volume 6 ‘Road Geometry’, Section 1, Part 2, (February 2005) London: TSO for Highways Agency

I'm starting to have doubts it's actually hit.....

There is an overhead gantry at the same height a few yards earlier. Surely the excavator would have hit that first?

Also the breaks in the bridge look to be clean breaks, I would think being hit would give a broken area not clean.

Reported no arrests made, would this not be procedure for causing such an incident unless they thought the driver wasn't at fault.

this photo shows the details of a possible construction company carrying out work. Was there a known weakness in the bridge already to be undergoing work?

The piece that fell was a separately-made beam that was dropped in place on bearing ledges (at the "clean breaks" that were clearly visible e.g. on Street View). Thus (as noted earlier) it was just pushed off its ledge and fell.
 

The bridge sloped across the road and may have been a little lower over the hard shoulder (though it's not supposed to be and probably wasn't when it was new either).

But even if a roadful of structures are all supposed to be a single regulation height, you'll find one is the lowest and that's the one that gets hit first.

Currently the gantry and that footbridge would have higher minimum clearances than solid bridges, specifically to avoid the additional hazard of bits falling on the road. I'm not sure that was the case when the footbridge was designed.

From their signage, the contractors were working on the parapets, so presumably not the bridge itself.

I was also wondering about it being a new footbridge for the same reason but reading about it online they are/were working on it to make the barriers either side higher to stop people being able to throw things over onto the motorway.. So it can't be that new then

This bridge appears to consist of 2 cantilevered sections which meet in the middle: from the pictures the intact section looks undamaged so presumably, from the structural point of view, could remain in place for the time being.  However, it may be distracting for motorists approaching it!

The low loader with the digger on it was presumably travelling at quite low speed as it was on the hard shoulder, and the digger does not seem to have moved much on the trailer.  The impact was close to the strongest part of the bridge.  I’m just surprised that the bridge came of worst in this impact – I wonder whether the quality of construction may turn out to be an issue.

One doesn't know what the diggers arm was doing/angle at which it collided with the bridge.....

13.7 All moveable assemblies such as jibs, brackets, booms and cabs etc. must be left in the position recommended for transportation by the manufacturer and must be secured to prevent movement relative to the main body of the machine.

13.4 High loads may endanger bridges etc. over roads, so when these are carried it is essential that the driver know the exact height of the load, and the width of the load at that height.

After all the Highway Code is only a code of Practice and failing to observe that does not go down well in Court in the event of an accident. 

Many of the rules in the Code are legal requirements, and if you disobey these rules you are committing a criminal offence.

Highway England’s chief highway engineer, Catherine Brookes, said: “Safety remains Highways England’s top priority. We worked hard last weekend to reopen the M20 as soon as it was safe to do so and I would like to thank drivers for their patience while we did this. The remaining section of the bridge has been assessed and is safe for traffic to pass underneath with a temporary 50mph speed limit.

“We naturally need to remove it under safe controlled conditions this weekend. We will use the closures to carry out as much work as possible, including barrier repairs, resurfacing and litter-picking. We will start planning the replacement in due course.”

For completeness: when the span fell it broke its back over the dumper truck it landed on. So there's no question of just popping it back in place.

I wonder whether it will ever be replaced. It was part of a footpath along what was a lane, but the next bridge either side is not far away, so it only serves a few houses on either side. There's no obvious destination apart from those houses, so it's not clear why that right of way had to be preserved.

Man due in court over M20 bridge collapse

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The bridge came down on to traffic on the M20 on one of the busiest travel weekends of the year

A 63-year-old man will appear in court following the collapse of a pedestrian bridge on the M20 during last August's bank holiday weekend.

The bridge fell on to the London-bound carriageway of the motorway just after midday on Saturday 27 August.

The man from Darlington has been issued with a summons to appear before Maidstone magistrates on 17 February.

He will face charges of dangerous driving and causing serious injury by dangerous driving.

He will also face three counts of criminal damage.

A motorcyclist suffered broken ribs when the bridge came down. No one died.

The collapse happened between junctions four and three, near the junction with the M26 which links the M25 London orbital with the M20.

The road, which is the main route to the Channel Tunnel and Port of Dover, had to be closed while two large cranes worked to clear the debris.

The road was closed again the following weekend for the remains of the partially collapsed pedestrian bridge to be removed.

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No one died in the collapse but a motorcyclist was hurt