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February 21, 2007

Why "road pricing" is a bad idea

Here in the U.K., our government has been making noises about “road pricing”, by which they mean a new tax based on the number of miles of road (and the types of road) that you travel using your car.

They claim that this will reduce congestion, however in order to appreciate the real effect of such a scheme you must keep in mind that:

  • Most Britons live away from where they work. This a result of industry consolidation, and of government policies such as the promotion of out-of-town shopping and industrial estates.
  • Congestion happens primarily during “peak periods”, i.e. the times at which people travel to and from work.
  • There is often little or no public transport provision to get people from residential areas to company premises. Even where there is public transport, it often takes a tortuous route, meaning that it takes much longer than travelling by car.

In other words, most of the people affected by road pricing will have little choice other than to pay the tax.

Not only that, but here in the U.K. we already have a pay-by-the-mile road taxing scheme, in the shape of one of the most extreme fuel taxing regimes of any country in the world. Not only does the government take around 50 pence per litre for unleaded petrol, but we actually pay VAT on the fuel tax!. So, of the typical 95 pence per litre we get charged for unleaded petrol today, around 14 pence is VAT, then there’s another 50 pence of fuel duty on top of that, so our government takes 64 pence of the money we pay for every litre of fuel. That’s a whopping 67.5% of the cost of petrol here.

Let’s consider for a moment what that means; say your car does 30 miles per gallon. There are 4.546 litres in an Imperial gallon (not a U.S. gallon, so please don’t try to correct me :-)), so that works out at an effective tax rate of about 10 pence per mile (more for a gas-guzzler). And all this without complicated vehicle tracking systems, extra paperwork, extra loopholes, or indeed any new laws from government.

So, if we effectively already have a by-the-mile charging scheme, why does the government think its new “road pricing” idea is the way to go? Put simply, because the public has already protested at the exorbitant taxes placed on fuel. Our government knows it would never get away with hiking the rate to the kinds of levels that it would like.

And in any case, raising fuel duty or imposing road charging schemes is unlikely to do very much to prevent congestion. Most of the people creating the congestion are simply trying to get to work, and they will continue to try to get to work under almost any conceivable tax regime. Public transport is not fit for purpose; from an employer’s perspective, it cannot deliver employees to the company’s offices reliably and on-time. From an employee’s perspective, it is dirty, unreliable, slow and often late; try to use such a service to get to many jobs in the U.K. and you would be sacked. Indeed, the situation is so bad that in Newbury, Vodafone runs its own bus services!

Increasing fuel duty or creating an expensive-to-operate road pricing scheme in the U.K. can therefore have only one result: inflationary pressure on the pound. The idea that it will have any significant effect on congestion is laughable.

February 14, 2007

PDFs and NSToolbar

One of the nicest new features in OS X 10.5 (Leopard) is resolution independence. Not only does this pave the way for a zoom feature that doesn’t pixellate as you zoom in, providing a better user experience for partially sighted users, but it also means that as display panel resolutions climb, the Mac OS X UI will stay a usable size and will just start to look much nicer.

So, Apple are trying to encourage developers to make their apps resolution independent. The problem with that, of course, is that it means everything must scale nicely (even to non-integer scale factors), and bitmaps just don’t do that easily. As a result, they’re suggesting that we draw several sizes of bitmap and stick them together into a multi-resolution TIFF.

That’s one way to go, certainly, but it does multiply the effort somewhat; drawing icons is hard enough without having to draw them several times at different scales and detail levels.

Anyway, some of us would rather use vector graphics where possible. (There have been some remarks about this already from the “you should use bitmaps” camp, which was later clarified after some criticism; it isn’t my intention to go into the pros and cons here).

So, away you go, changing your icons for vector graphics (probably PDF, on Mac OS X). For me, this was all working wonderfully, until I hit a stubborn problem. One of my toolbar icons, which looks like this

Go

was being rendered with a white square behind it whenever it was disabled or highlighted; i.e. like this

Go (Disabled) with a nasty white square behind it

This, of course, looks really bad, and I couldn’t work out why it only affected some icons and not others. Anyway, if you’re struggling with the same problem, a workaround is to call -setAlpha: on your NSPDFImageRep, giving the argument YES. The result in my case is that the problem went away:

Go (Disabled)

For people inside Apple, I’ve filed a bug report: rdar://4996913.