50/50....
going at that speed and overtaking a car with a junction approaching so soon?
As David's Mother says she wants motorcyclists to slow down (and in this case give more time to react and avoid the hazard).
But then again the car driver turning across the path, how could they not have seen the bike (or even apparently the car David overtook) approaching...regardless of whatever speed it was travelling?
As David's Mother says, she wan's car drivers to spend more time looking or checking for bikes!
I doubt many people can gage the speed of a narrow fronted bike travelling near 100mph from the front, i think the speed becomes more obvious as the bike gets nearer/ passes, who knows
Yes the speed gets a lot easier to judge the closer it gets, but its a lot more complicated than that and you might be surprised that a hell of a lot of people can, and very accurately, can judge the speed of a fast moving small vehicle (especially if they are exposed to it a lot, ie driving at speed themselves).
Its called Binoccular (or visual) Disparity and relies on the ability of the eyes/brain to calculate the speed of an object moving towards you by judging how quickly it changes in size from one moment to another. The bigger the object, the easier it is to calculate its speed if it is going fast as it as the changes in size are more obvious. Especially if there are two points relatively far apart on the vehicle (eg a trucks headlights) that get further and further apart from each other as it gets closer.
But, as you say motorbikes present a problem due to their very small size....when you have to make a fast decision.
Also apparently this causes a problem with unmanned level crossings in America with trains with only one light on the front....lots of accidents at night because people try to beat the train across but can't accurately judge their speed.
However, if you sit and give it a bit of time it becomes easier to judge (as the object has got closer).
So if in doubt...wait and see!
Interestingly enought the ability to use binoccular disparity to judge a vehicles speed is MAJORLY underdeveloped in children all the way up to late teens....which is why speed limits around schools are so reduced
http://www.bbc.co.uk/programmes/p0190msm
This ability also reduces as you get elderly......and also some people just can't grasp the skill at all.
One of the reasons I think a lot of people are on the road with a valid car licence that actually shouldnt be, and that a speed judgement test should be part of the driving test AS WELL AS an eyesight test.