[well OT] Tour of Brtiain Cycle Race

There can be local byelaws that enact speed restrictions, and those can be applied to classes of "vehicle" that are not called up the in national legislation. (so they could also apply to bikes, horses etc)

I wonder if there is a mobile phone app for a speedometer? Otherwise how would a cyclist or a horse rider know they were going too fast?

There are now dedicated GPS devices for cycles route mapping, speed, etc. However, you can still buy old-fashioned cycle computers. You attach a tiny magnet to a spoke, a detector to one of the front forks, and these days it talks wirelessly (rather than running a cable) to a display on your handlebars showing speed, max speed, distance, etc. You do need to measure the o/d of your tyre and enter that.

Any mobile phone with GPS can tell how fast it's going

Circumference.

Shame there is not a formula that the software could use to convert one into the other...

It’s more accurate to measure the circumference though if only because it’s longer and small errors will have a lesser effect on accuracy of the bike computer. An error of diameter will be multiplied by Pi whereas an error of circumference won’t be multiplied.

Usually done my marking the tyre and road where they meet and then rolling the wheel one full revolution and measuring the flat distance on the ground.

Tim

It might involve something odd - like µ

Indeed. Then we wouldn't have all this bollox about 'rolling radius' for wheels that are not perfectly round.

It is in fact impossible when your wheel dies not have a constant diameter. Only perfect circles have that.

What is the diameter of your waist?

It depends

It might have been reported by the media as speeding, but it would have been charged as the offence of riding furiously, under Section 28 of Town Police Clauses Act 1847.

The same section also makes it an offence to drive cattle furiously, although I've never seen any cattle on the road move faster than at a slow amble.

What about those wossnames in Spain?

British cattle are noted for being much more docile than Continental ones. They generally have a lot more contact with humans, so have been bred for docility.

certainly is, I've several.

It is high time that the law was changed so that all the relevant rules that apply to motor vehicles apply to bicycles, in the interests of having a level playing field and being seen to do so. So speed limits, one-way streets, stopping at red traffic lights and zebra crossings with people on them. I'd also like to see it made an offence to overtake a vehicle on that side that it is indicating to turn (usually the LHS), so a car which is indicating to turn left and is in front of a cyclist has priority over a cyclist wanting to turn left, but the HC has already been altered to

What is the legal situation if a cyclist is found to be over the legal alcohol or drug limit for motorists? Can he be given points on his driving licence if he has one, or are those offences on bikes immune from licence points? I've always wondered.

I think if it was my motorbike I'd have one fitted even if it was not a legal requirement and even if it was not authentic, so I was able to obey speed limits. Not being legally required to have one seems a *very* poor excuse, IMHO. Maybe I'm just too law-abiding for my own good ;-)

We have the "sense" you request in my country. for a guarded turn.

I've erased my long rant on the topic, but if you think about it, neither option is all that good. And part of the problem, is "abuse of feature" and "expectations". The "law" may seem simple, yet humans have all sorts of shortcomings, and it's those shortcomings that affect outcomes.

To give an example of human foibles, in the Drivers Handbook (you know, that thing they give you, that you're supposed to read :-) ), it says on a four lane highway, where there are two lanes in one direction of traffic, "two cars are not supposed to drive parallel to one another", and "keep to the side, except to pass". We have to explain protocol to people, because they're too stupid to realize "hey, if I drive parallel to that other driver, I'm holding up traffic". It is these sorts of details, explaining the obvious to people, which is the crux of neither guarded turn idea being all that good. That's what my rant was about. My "state diagram" for bicycle driving.

I don't really want to explain all the nuances, and things that have happened to me, because you'll think I'm a loon.

The law may wish to do certain things, but for practical reasons, the penalties possible are different for cyclists. You can be fined. That much seems certain. By charging you with something that cannot be enforced though, and causing you to appear before a magistrate, they could convict you of "careless and inconsiderate cycling". I don't understand why they could not issue a breath test.

I did hear tale of someone getting their car written off by a cow - He was following down the road a little bit to close to a heard on its way to miking. One decided sit on the front of the car!

The main reason seems to be the working the the road traffic act of 84. It gives a long list of *motor* vehicles of various classes and what speed limits apply in various cases. Cycles are simply omitted from the list.