document: We're the same age, and we have both been assailed and corroded by the bracing weather around the Firth of Forth.
  Both have been carrying somewhat more of a load factor than is either assumed or advisable in the design spec.
  There are significant differences, though. I have not been closed until the New Year, while essential repairs are carried out.
  Nor have I become indispensible to the Scottish economy. Oh no.
  The closure of the bridge represents a significant challenge to those on both the North and South Queensferry sides, and extending a long way around.
  Hauliers use it to go north, and not only to Fife, but to Dundee and beyond, to Aberdeen and the north east.
  Likewise, they bring goods south in supply chains affecting the Lothians and beyond.
  One of those supply chains is to households, in that a lot of Christmas shopping is being done by road freight. This is by far the busiest time of year for the Amazon 'fulfilment centre' (warehouse) in Fife.
  Inbound and outbound deliveries look a lot more expensive.
  Among many others, the route is important to Diageo's gigantic bottling plant in Cameronbridge. It trucks containers of whisky and its other spirits to Grangemouth and the Clyde for export, and south to distribution depots in the English Midlands.
  Hauliers going round by Dunblane or the Kincardine or Clackmannanshire bridges face extra cost in both extra miles and traffic delays.
  That's just the commercial traffic. The road bridge has also become a vital link for workers, most commuting from northern homes to south workplaces, but some going the other way.
  Fife has some big specialist employers, including Babcock's Rosyth dockyard, Sky's contact centre, Bank of Scotland card processing at Pitreavie and the Raytheon weapons systems in Glenrothes. (The latter makes the Paveway bombs which are now being dropped on Syria by RAF Tornados.)
  The busier south-bound traffic in the morning demonstrates one of the big shifts that has taken place in the Scottish economy in recent decades: Edinburgh has been transformed from a modestly-sized city into a large travel-to-work region.
  That, in turn, has re-shaped southern Fife, as you can see in dormitory estates from Dunfermline to Dalgety Bay and beyond.
  On BBC Radio Scotland's Newsdrive, the call went out from the Scottish government for employers to be understanding of the difficulties now facing commuters who would normally use the Forth Road Bridge, or whose train services across the rail bridge face becoming impossibly busy.
  Transport minister Derek Mackay suggested altered shift patterns and car sharing. There could also be more home working.
  And that's where - in the dark days of a traffic-stricken December - there could be a silver lining to this large logistical cloud.
  Recent research shows that when people are forced to re-think their travel plans, a significant number discover that they prefer the new routes.
  This was based on the London Tube strike in February of last year, using the big data sets available from the Oyster cards, which track Londoners use of the Underground.
  The strike closed some stations, but not all. And when Shaun Larcom of Cambridge University, with Ferdinand Rauch and Tim Willems at Oxford University, compared the disrupted traveller with the undisrupted, they found that one in 20 of the disrupted travellers abandoned their old travel plans in favour of new ones.
  There are, of course, numerous explanations for this, and some which could only apply in London.  One is that distances are distorted on the design classic of London's Tube map. This is what economists call an 'informational imperfection'.
  Only when people were forced to re-think their journey did some discover they could get to their destination faster by using an undistorted map.
  These economists, in an article published by the Centre for Economic Performance, concluded it could also have a lot to do with the 'search costs'.
  That is, the hassle of finding out other means of getting to work was more costly than the advantages perceived as likely to come from doing so.
  Yet the advantages of changing their behaviour were quite high, so it is reckoned that there must be a more persuasive reason for commuters to avoid either maximising or optimising their commute.
  Instead the Londoners had been 'satisficing' - that is, opting for an outcome that is merely satisfactory, often because it is familiar, rather than striving to find the best possible solution.
  "Many London commuters failed to find their optimal route until they were forced to experiment," wrote these researchers.
  And it turns out the Tube strike had a positive outcome - possibly not what was intended by the late Bob Crow, general secretary of the RMT union:
  "The long-lasting benefits of shorter commutes are worth more than the total travel disruptions during the strike," say the economists.
  They reckon they now have evidence to back up business strategy guru Michael Porter when he offered the "controversial hypothesis that imposing a constraint on an economic system can enhance efficiency over time - as constraints force people and organisations to experiment, innovate and re-optimise."
  So while the Scottish government, local councils, ScotRail and bus operators seek out ways to handle the disruption, one suggestion is to use apps to 'nudge' people into thinking laterally and of alternatives.
  The challenge falls to individual travellers, to go Forth and re-optimise.
summary: The Forth Road Bridge and I have a sort of affinity.