An Irishman's Diary

TRAVELLERS on Dublin’s Dart and Luas lines will have found themselves wrestling with some profound questions this week, the following included: “If you are skating along on roller blades in a frictionless environment, will you ever stop moving?” The questions are part of a campaign to increase awareness of physics, and they come with multiple-choice answers, in this case (a) yes; (b) no; (c) need more information.

I hope I’m not spoiling it for commuters by suggesting that the answer to the skating question must be (c). Because although, of course, Newton’s first law of motion states that a body at rest will remain at rest and a moving body will continue moving in a straight line until a force acts upon it, there are many potential complications to consider.

If you tried skating in a straight line in Dublin, for example, one of the first forces likely to act upon you would be the Garda Síochána. All the more so from next week, when the humorously-titled Operation Freeflow is launched and there will be officers at every junction, causing not just roller-bladers but cyclists to turn into law-abiding citizens overnight and to pretend that they always stop at red lights, while trying not to blush.

If you do happen to skate through a light, the force will act upon you even more directly. This is especially true if you’re unlucky enough to be intercepted by a member of the Garda Dramatic Society. But either way, your interceptor will invariably start by posing his own multiple-choice question.

There is a list of these questions they learn at training college, including “Did you notice that stop sign back there?” and “Would you care to explain to me what you just did?” What they all have in common is that there is no possible answer that reflects well on you. Except maybe (c), “need more information”. And that will only buy time.

Anyway, getting back to our theoretically frictionless rollerblader, gardaí aside, there are other issues to consider. Assuming an environment free of atmosphere – air itself being a cause of friction – does the skater have an oxygen tank and breathing apparatus? Is the course ahead perfectly flat? Or are there hills that will convert the skater’s kinetic energy into gravitational potential energy, resulting in deceleration? Then we must also ask whether – even in theory – a perfectly friction-free surface to skate on is possible. Yes, yes, I know there have been exciting things done recently in nano-technology: specifically in the area of “superlubricity”, whereby crystalline surfaces are designed to minimise friction, if not eliminate it.

Indeed I hear that graphite substances are now being used to an extent anticipated by the famous Prandtl-Tomlinson Model (often misrepresented as the “Tomlinson Model”, which unfairly ignores Ludwig Prandtl’s groundbreaking 1920s work on the plastic deformations of crystals). But – oh dear – I sense I may be showing off now. My apologies, reader. Let me just reiterate that my answer is (c) and leave it at that.

FOR SOME REASON,mention of lubricity – which my dictionary defines as "slipperiness, smoothness, oiliness" – reminds me of politics. (Fun question: If you are experienced career politician and are speaking in a friction-free environment – not Tonight with Vincent Browne, obviously – could you go on for ever? Answers on a postcard, please). Which in turn brings me to an issue exercising our letter writers: whether ministerial cars should be allowed to use bus lanes.

It seems to me that this is part of a wider question that needs to be asked about such lanes. Because at a time when inefficiencies everywhere in the public sector are being challenged, the distribution of urban road space is one of the worst offenders of all.

Yes, bus lanes should be a fast way of commuting, and should be seen to be such. But when traffic in one lane is bumper-to-bumper, and the neighbouring lane is empty – as is often the case – the optimum overall flow is clearly not being achieved.

This is a problem, I suggest, that could be solved at a stroke – literally. In short, my idea is to reopen bus lanes to any drivers prepared to pay for the privilege, while pitching charges at a level that would discourage mass participation. Yes, essentially, we would thereby create first and second class road travel (or “business” and “economy” as the lanes would be officially promoted). But the same is done in air and rail, with no objections.

The users of the new business-class lane would, after all, be subsidising improved traffic flow in the economy half of the road. And to the extent that bus-lane rental facilitated genuinely urgent business – of the kind ministers are always presumed to be doing – society would benefit in other ways. As for frivolous users who paid to use the bus lanes just because they could, well, their charges would be a tax on snobbery.

Speaking of which, there used to be an expression in Ireland for those of supposed high birth: ie “the quality”. It was often used ironically, or with sarcasm, to denote also those who considered themselves a cut above, with or without justification. And this is what I mean by suggesting the problem of improving traffic distribution could be solved at a stroke.

The stroke I have in mind is the one that shares a keyboard button with the question mark: ie “/”. Strategically inserted in the existing term “Quality Bus Corridor”, it would denote a new two-tier road system, henceforth termed the Quality/Bus Corridor. The two classes of user would thus be identified. Meanwhile, another much-needed source of exchequer funds would start flowing.