So here’s fun thing bouncing round the nerdier corners of the internet in a “LOL, what” kind of a way:

Architecture practice PLP is soon to reveal their concept design for CarTube, a revolutionary solution for transportation in cities such as London.

“CarTube”? A car, and yet also, a tube? Whatever could it mean?

The concept combines two existing modes of transport – automated electric cars and mass public transit – into a single, seamless underground road system.

Users will be able to book a CarTube trip in their own cars or shared public cars through a smartphone app.

There will be an underground transport network that moves cars in a continuous flow at a steady speed, increasing transport capacity, relieving congestion and freeing up public realm above ground.

Lars Hesselgren, Director of Research at PLP will officially unveil CarTube at a conference on the 2nd December at the Institution of Mechanical Engineers (IMechE) HQ in London.

I would say that I have some questions for Lars.

In some ways it’s a bit cruel to do a sanity check something like this, because it’s so obviously incapable of withstanding it. Indeed, it was probably never intended to: my suspicion with these things is always that the real point of the exercise was to mock up a pretty picture in the hope of free publicity. (Possibly not the kind of free publicity I am offering right now.)

But what the hell, let’s do it anyway:

1) It’s quite difficult digging tunnels in London because there’s so much stuff already under the ground (electrics, gas, sewers, the actually existing Tube). At Tottenham Court Road, the Crossrail tunnels run between two existing bits of tube architecture, with under a metre of clearance.

So I’m going to go out on a limb and guess that there probably isn’t enough space under London’s streets to create significant network of TubeCar tunnels, thus rendering the whole thing a bit silly.

2) That specific point on the Victoria Embankment, courtesy of Sir Joseph Bazalgette, contains one of central London’s most important sewers. So it’s probably not the best place to start.

3) While we’re at it, it also contains the District and Circle lines. You almost certainly couldn’t put the CarTube there, is my point here.

4) Why are the cars underground so tiny? Do they get miniaturised as they go through the portal? Is that it? Is this the bit of the plan they’re going to reveal at their press conference this week?

5) While we’re talking about portals, I’m guessing there probably isn’t enough space on the surface in London to create them either.

I mean, on this mock up, they’ve put the entrance to the tunnel on the site of an existing road, thus implying that we wouldn’t be losing any more space to car traffic. Except that, in this parallel universe, roads clearly still exist to do the first and last leg or your journey, or you wouldn’t need a portal in the first place. Soooo… where are the portals going to go? Which roads will stay and which will go? Will there be an enquiry?

6) Come to that, where are all the vehicles that aren’t part of the CarTube system meant to go? Are they just banned from Westminster now? Parliament is still going to need goods deliveries. Are they all meant to take the CarTube? Is the Prime Minister’s car?

7) To be fair, maybe I’m being unfair with all these questions, and this is actually just a nice plan to make the Victoria Embankment into a park. By ripping up the Circle line.

8) In the real world, this is where the east-west cycle superhighway runs. They’ve ripped that up, too. Great work, guys. Fantastic work.

9) Bit worried about those people cycling on that narrow path, shared with pedestrians, without any barriers stopping them from falling in the Thames, too.

10) That said, in this fantasy world, every bridge can be a garden bridge. Look how garden-y Westminster Bridge is! If we did this at least we wouldn’t have to build the actual Garden Bridge, I guess. So that’s something.

Jonn Elledge is the editor of CityMetric. He is on Twitter, far too much, as @jonnelledge.

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