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Comment by mbrookes | Hacker News Reader

3) Are typically petrol (gas) rather than diesel, and are often hybrids (less pollution).

Edit: Not significantly smaller, as pointed out below 4) Are typically more compact than a black cab - take up less road space

So no, it's not about congestion in that sense. What the author appears to be suggesting is that there are more cars on the road plying for the same trade, and the more journey miles taken in an Uber, the more idle time a black cab will spend waiting to be hailed - either congestion on the road, or congestion in the taxi ranks.

However, if that were the true ulterior motive, that could be applied to any car service that competes with black cabs, not just Uber.

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> 4) Are typically more compact than a black cab - take up less road space

I thought "that can't be right, black cabs aren't all that big". And a quick search suggests that a Prius and a TX4 black cab are pretty much the same length - 454cm (Prius) vs 458cm (cab).

The black cab is 18cm wider, which may make a difference, although length seems the more significant dimension here. And black cabs are much taller of course.

Huh, seems perception is not always reality. Thanks for fact checking!

18cm could make a difference navigating some of our narrower streets, but my mental image was that there was a more significant difference than there actually is.

I've edited my original comment.

5) Don't drive in bus lanes (black cabs can and do drive in most bus lanes; other cars cannot, regardless of number of passengers).

How is this an argument against black cabs? Bus lanes in my city are usually empty. Allowing cars on bus lanes would actually lower congestion.

For the record, London is a city where for some major routes, there's buses every 2-3 minutes. They're a major part of the public transport infrastructure in London. Bus lanes in much of the city centre are never empty.

The simple answer, then, is that black cab drivers are tested on successfully fitting in with the flow on bus lanes so that they don't slow down buses, and minicab drivers are not.

Also for the record, here's a quote from a different post by the same parent:

> 3) I used to drive to and from work every day. Part of the journey took me along the A4/M4 towards Heathrow. There was a traffic jam every day, going home from work (towards Central London). This busy road had a bus lane. I don't recall ever seeing a bus going past me in that lane, but plenty of black cabs did. I don't see why a black cab should get to skip past the rest of us waiting 20 mins in traffic.

Perhaps there are some bus lanes in London that are very very underused and should be turned into regular lanes. Perhaps the people in charge of roads have discovered that if they were to remove that bus lane, the result would be congestion further into the city in a location less able to handle it than a motorway. Perhaps, for operational reasons, the buses absolutely need to be able to bypass traffic on the motorway.

As for black cabs, perhaps it would be a complete hassle to implement a "no black cabs" rule for that one road just to avoid upsetting people who chose to drive into London.

There's all sorts of potential reasons for that bus lane existing - and there's a very good chance that if someone were to file a FOI request with TfL, they have a report on the potential results of removing that bus lane.

> Perhaps the people in charge of roads have discovered that if they were to remove that bus lane, the result would be congestion further into the city in a location less able to handle it than a motorway.

It's a well-known controversial bus lane, which became a political issue. Anyone complaining about it loses my respect on HN, as they didn't look at the traffic engineering problem, just the Daily Mail hate.

The motorway is 3 lanes until the final stretch into London, which has two lanes. The width reduction isn't at a junction, so the extra lane didn't help traffic flow -- it just caused congestion and collisions by making drivers merge. The lane was ended at the preceding junction's slip road, and a bus lane continued for the spare length. This improved journey time for buses (a minority of vehicles, but a decent proportion of people), and also improved journey times for cars!

But, the sight of the bus lane annoyed the Tories, so they got rid of it.

https://en.wikipedia.org/wiki/M4_bus_lane

https://waronthemotorist.wordpress.com/2010/11/22/the-m4-bus... is where I first heard about it (I lived in London at the time, but didn't have a car.)

Sounds about right. Major roads in the UK tend to be remarkably well-engineered, and if you can think of doing something to them, there is almost definitely a document explaining the exact repercussions of doing that and how much it'd cost.

"Allowing cars on bus lanes would actually lower congestion."

That's an argument to get rid of bus lanes, not to allow some protected class of cars to be permitted to use them.

Anyway, bus lanes aren't about reducing congestion overall, but reducing the congestion faced by users of buses.

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