Yesterday I tested Lothian Buses' claim that 20mph restrictions would cause their services to become commercially unviable.
They say the number 38 "can only be operated with financial support from the council, therefore any increase in operating cost would have to be passed to the council for an increased subsidy."
I rode the number 38 at 7pm (so outside rush hour) from the top of Esselmont Road west towards the canal and Slateford.
Here's a sample of the heady speeds I was travelling at:
25-26mph : 22s
23-24mph : 36s
20-22mph : 1 minute 45s
<= 20mph : 7 minutes 52s
22 seconds at 26mph would take 28.6 seconds at 20mph
36 seconds at 24mph would take 43.2 seconds at 20mph
105 seconds at 22mph would take 115.5 seconds at 20mph.
The absolute worst case scenario would see an increased journey time of 24.3 seconds even if the 20 zone was extended to cover the route of the number 38 for three miles (far longer than is actually proposed).
In reality of course, the bus often had to wait at traffic lights. If it got to the lights a couple of seconds later this would have no implication on journey time, it would merely have had to wait less time for them to change.
The actual distance involved is well under a mile, so we might expect a "cost" of something like 8.4 seconds.
Does the 20mph proposal really sound like something that would bring an entire bus service to its knees - or is it just a cynical knee-jerk reaction from Lothian buses without bothering to calculate the tiny effect the proposals they've scuppered would actually have?
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