[sustran] motorcycles and congestion

[Pascal Desmond]

>Does anyone have any statistics about motorbikes and passenger car
>equivalents, or passengers per hour per meter of road width?  I'm trying
>to get some idea of the role motorbikes play in congestion.
>
>thanks
>Walter Hook
>ITDP

Hello Walter

And to everybody else who participates in sustran (If memory serves me
correct, I haven't sent a msg to sustran before).

I'm a transport activist in Lancaster, England (with Transport 2000 North
Lancs.), and I work on the journal World Transport Policy & Practice,
edited by John Whitelegg. I hope you all like my signature - this is my
activist's hat. I have a different one which I use in relation to the
journal.

Anyway, mo'bikes. A couple of years ago I had the dubious pleasure of being
torn into by the local motorcycle lobby who pointed out how little
congestion they cause. I responded with one of those occasional flashes of
pure genius that afflict us all only too infrequently.

I asked them if they were familiar with the 2-second rule ('only a fool
breaks the two second rule' takes approx 2 seconds to say - you watch the
vehicle in front pass e.g. a streetlamp and then speak aloud 'only a fool
breaks the two second rule'. If you reach the streetlamp before you finish
speaking, then you're too close to the vehicle.).
Naturally, the motorcyclists keep back more than 2 seconds from the vehicle
in front 'That's why we're still alive'

Doing 30 mph means that they will cover 30 yards in 2 seconds. It's
actually 29.33 yards. Plug them into a spreadsheet (there's one tab between
each column of data) - it is basically 1760 / 3600 * 2. The metric numbers
aren't quite so amenable.

vehicle speeds and the 2 second rule.

speed in mph
	distance in yards travelled in 1 hour
		distance in yards travelled in 2 seconds

			speed in kmh
				distance in metres travelled in 1 hour
					distance in metres travelled in 2
secs


10	17600	9.78	10	10000	5.56

20	35200	19.56	20	20000	11.11

30	52800	29.33	30	30000	16.67

40	70400	39.11	40	40000	22.22

50	88000	48.89	50	50000	27.78

60	105600	58.67	60	60000	33.33

70	123200	68.44	70	70000	38.89

80	140800	78.22	80	80000	44.44

To all intents and purposes, you can say that speed in miles per hour is
the same as the number of yards covered in 2 seconds.

Sticking to the 30 mph example, they agreed that in reality they would stay
back 40 yards to allow for the unpredictability of car driver behaviour. I
pointed out to them that if that is true then, even though they have a very
small footprint when stationary, they take up more roadspace than a car
when in motion. Funnily enough, they've never raised the argument that
motorcycles create less congestion with me since.

Kind regards,
Pascal.

"Never doubt that a small group of committed citizens can change the world,
indeed it is the only thing that ever has." - Margaret Mead, (1901-78)

Thanks to the legal eagles at the RAC, here is a very nice piece of the law
(sadly, unreferenced):
"There is a fine of up to £2,500 and as many as 9 penalty points available
for any motorist who drives through a puddle and splashes pedestrians".
It is advisable that anyone who gets splashed should have at least two
independent witnesses, and have one of the nice, shiny CCTV cameras
pointing at you Š and don't forget that
"Police are required not to show 'favour or affection' towards some and
'malice or ill-will' towards others" (Police Act 1964, section 18 and
Second Schedule).