No, I don't mean exponentials - as a mere economist, I can just about manage them!

It just that, in writing a report, they will typically write 'The system needs 28 no. point ends' when it actually needs 28 point ends.

There was an example in a magazine I was reading today - a building was being protected from earthquakes by 'using 292 nos. pendulum seismic isolators'.

This seems odd. Can some engineer - or some teacher of engineers - tell me what the rationale is, please?

An IATA official has recently been quoted as saying that, 'A slot management system is indicative of a failure of governments or airports to invest in adequate infrastructure to keep pace with airline demand.'

Should governments and airports always invest to meet airline demand?

Consider the issue of de-peaking. Until recently, airlines worked on a hub-and-spoke basis, scheduling large numbers of flights in and out of hub airports in 3-4 waves each day - early morning, lunch time, late afternoon, and evening. They all connected with each other and then flew off again.

Surprise, surprise - this caused overloading of facilities at peak times and under-utilisation out of those peaks. What did airlines do? Why, they de-peaked at key airports.

Aircraft still came into hub airports in those waves, but their departure was sometimes re-scheduled so that the peak load on check-in and baggage staff was reduced.

So - by IATA's argument - airports should have invested in capacity for the peak caused by the historic hub-and-spoke operation when that became fashionable. They would, of course, then have been left high and dry by the subsequent de-peaking, having invested in long-life assets which the users no longer wanted!

Consider the fact that aircraft are mobile assets and airports are not. Some airlines will - rightly - try a route for a season or two to see if they can make money out of it. If they can't, they pull out. So what should the airport do? How much should they invest for an operation which might not last beyond tomorrow?

And consider the impact of frequent flights by small aircraft or less frequent ones by larger aircraft (an issue studied, incidentally, in ACRP Report 31, available on the TRB web-site).

If an airline schedules a 50-seat plane every half hour instead of a 100-seat plane every hour, it takes up twice as many slots for the same number of passengers. OK, on this one you could argue passenger convenience - all other things being equal, people prefer frequency. But is it really worth it - is it a good use of scarce runway and slot capacity?

Is it worth increasing capacity - as IATA suggests - for this kind of thing?

To me, the killer argument here is that of San Diego. This is the busiest single runway airport in the United States, handling 17 million passengers a year. It has spent much time, money and effort looking for ways to increase capacity because, it is said, it's full.

But look across the Atlantic, to Gatwick - the busiest single runway airport in the world, handling exactly twice as many passengers! The key difference is aircraft size.

The predict and provide policy - predicting demand then providing infrastructure to meet it - has been discarded in other areas. How much does IATA need to catch up with this? Because another leading IATA manager has been quoted as saying that airports should use their charging system to re-distribute traffic - a peak charge signals the cost of the additional infrastructure needed for the peak.

A colleague recently moved from the aviation industry to the rail industry. The key difference he noticed was that the former was always planning for growth, whereas the rail industry was planning for a steady state.

This led me to wonder what the aviation industry would look like if it wasn't always growing! I have as yet come to no conclusions, but there was an interesting presentation at the TRB Annual Meeting in January which showed that air passenger growth might be slowing significantly.

And, logically, it cannot continue. In my lifetime, fares have continued to drop in real terms, and this has led to the growth in air travel we have seen. Can this go on?

Your thoughts would be appreciated!

I was very interested to read 'The New York City pedestrian safety study & action plan', published by the Department of Transport this month - see the New York City web-site.

Headline facts are that
pedestrians are 10 times more likely to die than a motor vehicle occupant in the event of a crash,
pedestrians accounted for 50% of traffic fatalities in 2005-2009,
36% of crashes resulted from driver inattention,
27% of crashes where pedestrians were killed or seriously injured occured when a motorist failed to give way,
80% of crashes which kill or seriously injure pedestrians involve male drivers, and
79% involve private cars.

New York City is relatively safe as American cities go - there are 3.49 traffic fatalities for each 100,000 of population (compared with Atlanta at 10.97 and Detroit at 10.31). But London has 2.10 and Stockholm 1.23. Since national fatality rates are 12.2, it must be pretty deadly out in the sticks!

Since 2004, the number of traffic fatalities in New York City has been lower than in 1910 - which is impressive!

Pedestrian fatality rates were 1.8/100,000 of population in 2008 - again much lower than Atlanta (11) and Los Angeles (7.6).

Vulnerable road users - pedestrians, cyclists and motor-cyclists - accounted for 71% of the city's traffic fatalities.

A telling quote from the report is that, 'Drivers can usually be expected to behave in ways appropriate for their own safety but may not always have the same commitment to the safety of people outside vehicles'.

A disproportionate number of pedestrian crashes in Manhattan were on major 2-way streets.

Wide roads also accounted for more pedestrian crashes - this reflects much other research which shows that widening roads reduces safety.

74% of crashes involving pedestrians were at intersections (it's 24% in the rest of the USA). Nearly half were at signalled intersections: 57% of these occurred when the pedestrain was crossing with the signal.

Pedestrians are more likely to be killed or seriously injured when crossing with the signal than against it, although crossing against the signal is more likely to be fatal.

Driver inattention was a factor in 36% of crashes: these were more than twice as likely to be fatal than others. Driving while using a mobile phone is more dangerous than drunken driving.

Speed is also an issue. A pedestrian struck at 40 miles/h is 4 times more likely to die than one struck at 30: one struck at 30 is 6 times more likely to die than one struck at 20.

As a result of the study, an action plan has been drawn up. High-crash corridors are to be identified and targeted, and countdown signals are to be installed at more crossings. The State legislature is to be pressed to allow more red light cameras (only 150 are allowed at the
moment) and speed cameras (currently illegal in New York City).

The city's target is to halve traffic fatalities between 2007 and 2030: they are currently a bit ahead of traget, with 256 fatailites in 2009.

The rail connection to Bangkok's Suvarnabhumi Airport opened today - and it looks good, with a choice of an Airport Express or a commuter train as well as in-town check-in facilities at the Airport Express's downtown terminal.

I had a look at the airport's web-site to see how well the link was publicised - after all, it could bring both business and prestige to the airport.

I went to www.bangkokairportonline.com then clicked on Transportation then on Airport Express - and got details of the express bus service into the city!

You have to click on Rail Link to get any information about the railway - and that is badly out of date. Full service is expected in early 2010! There are no links to the airport railway (note to searchers - it's on www.bangkokairporttrain.com).

Sad - and a waste of a valuable resource for the airport.

There are debates about what an Airport Express really is - express laundry? express coffee?

In Bangkok, it's the four bus routes who got in first with the brand name. In Chicago, it's the minibus (or shared-ride van) service.

It's a pity - from the customer information point of view - that we can't standardise on this!

Probably the best name is the one in (Wien) Vienna. The stunning airport express there is called the City Airport Train - what could be clearer than that?

A colleague has made the interesting suggestion that it may be time to rethink how classes of service on trains are described or branded. He comments that the standard of accommodation on many first class train services is similar to premium economy on an aircraft.

He also speculated that occupancy might rise if the service was branded Premium or Business Class, since most companies have a travel policy which is aimed at finding the best business class service.

In addition, he raises the question of airlines which offer a rail service as a complimentary feeder service between airport and specific domestic destinations for certain fare types. Should this be a premium rail service for a premium air traveler? This is likely to depend on the traveler profile and the policy of the individual carrier.

Fascinating stuff!

As an economist, I approve of the concept of providing a number of classes and therefore a number of prices. It helps to maximise revenue, and it improves customer choice.

However, one needs to be culturally aware - in particular, of what to call the two classes.

In Japanese trains, there is Ordinary Class and Green Class. On some, you pay less if you have to stand: you can also have a compartment in Green Class which costs more than the ordinary Green Class, effectively making 4 classes.

On the Dubai Metro there is Gold and Silver Class.

I'm glad the UK rail network changed form Second Class to Standard Class: the argument was that you shouldn't be calling 80% of your passengers "second class"!

Heathrow Express had a big debate about what to call its classes: they decided on First and Express (and the term 'Express' was my idea!). First and Business was decided against, on the grounds that lots of people weren't travelling first class and were not travelling on business!

Amtrak provides coach and business class on the Acela Regional trains, and business and first on the Acela Express.

I was fascinated to learn recently about the Club Car on New Jersey Transit. A group of people pay to have a dedicated car attached to one peak train each way: the car has more comfortable seating and more leg-room than the average commuter car. Passengers pay their fare to NJT and a supplement for travel in the Club Car. You can pay by the day or for a month.

Moving on to the second point, I'm pretty sure that those airlines which offer complimentary rail travel in conjunction with a flight only offer first class. I also understand that the take-up of rail is good - at one stage, people like Virgin Atlantic and Emirates were offering their preferred passengers a choice of a limo or Gatwick Express to London, and most chose the train because of its reliability.

On both the Stuttgart and Cologne to Frankfurt and the Brussels Midi - Paris CDG air-rail code shares, all rail travel is in first class.

One reason for the unpopularity of the short-lived code-share between SN-Brussels and Thalys on the Paris Gare du Nord - Brussels Airport sector was that rail travel was in Confort-2 class and not Confort-1.

I'm not sure what happens on other rail-air code-shares.

It was also interesting to see that American Airlines now offer what they call Express Seats! Customers can buy seats in the first few rows of Coach, including bulkhead seats. In addition to sitting in the front of the main cabin, the Express Seats option also includes being in Group 1 of General Boarding, providing the benefit of being among the first Coach customers to board the plane. Express Seats can only be purchased at airport Self-Service Check-In machines between 24 hours and 50 minutes before flight departure, on flights within the United States, Puerto Rico and the U.S. Virgin Islands.

This has been done by Ryanair for a while - passengers can pay a priority boarding fee to be among the first to board - and therefore to have the best choice of seat. I do not know whether there is any limit on the number sold - could everyone buy priority boarding?

So what do you think? Should first class rail be re-branded? To what?