Edbear
22nd July 2007, 13:18
Height Kills
By Andrew Bent
The traffic engineer was quite pleased with himself, he had finally managed to stop the local bus drivers trying to take their double deckers under the low bridge under the railway, so Councillor Prescott might finally concede that he knew what he was doing. But as he entered Prescott's office he saw that the councillor was in an ominously thoughtful mood.
'I see we've had a reduction in accidents in Railway Terrace' said Mr Prescott, 'Yes' said the engineer, anxious to demonstrate his success, 'You see I did a survey and found that the maximum safe height under the bridge was 12'2", so I arranged for some warning signs to stop anyone taking a vehicle more than 12' high...'
But the Councillor had already lost interest. 'I've been studying some statistics' said the Councillor (the engineer winced, Councillor Prescott's grasp of mathematics was notoriously shaky) 'and it seems that when those new warning signs went up the average height of vehicles using Railway Terrace fell by 9 inches', 'Well, yes..' replied the engineer, 'and accidents dropped by 18%' continued the Councillor triumphantly'. The traffic engineer tried to figure out where this was leading, 'Do you realise what this means? Every inch of average height reduction leads to a 2% reduction in accidents! All we have to do is alter the warning signs to read 11' and accidents will drop by another 24%!'
His head spinning, the traffic engineer tried to reason with the Councillor, 'but if a 12 foot vehicle can get through perfectly safely, what is the point in imposing extra restrictions?' Councillor Prescott was having none of this, 'you don't seem to understand, Height Kills, if every inch of height reduction causes a 2% drop in accidents, surely we must have a height limit reduction program, let's speak to the bus company and see if they can lower the single deckers somehow.'
The traffic engineer thought quickly, there was no point in trying to explain the facts, Councillor Prescott always regarded knowledge of road traffic and accident causation a fatal disqualification for making decisions on the subject, but there was a possible way to turn the situation to advantage. 'There is another low bridge, under the disused railway in Beeching Close, where lorries do sometimes get stuck, but I haven't had the funds to tackle the problem before, I suggest that should be the first priority for the height reduction program'. Councillor Prescott agreed and the traffic engineer set off for Beeching Close with measuring rod in hand.
At first it wasn't clear why there was a problem at this particular bridge, there was already a height restriction of 7 feet, so why on earth were drivers ignoring it? After an examination of the bridge the reason became clear, the maximum safe height was over 14 feet. On receiving a recommendation that the 7 foot height limit was unrealistic and should be raised, Councillor Prescott was apoplectic, 'lorries are getting stuck because they are too high' he yelled, 'surely the limit needs to be lowered'. The engineer tried to point out that it was precisely because the limit was obviously ludicrous that it was being ignored, and that raising the limit would increase compliance, but the Councillor did not understand. 'In Railway Terrace, reducing the height reduced accidents, therefore Height Kills' he argued, 'surely raising the limit in Beeching Close will increase average heights, therefore increase accidents,' 'But it isn't the average height that matters' the engineer tried to point out, 'a 14 foot limit will be taken seriously and will reduce instances of excessive height, therefore reduce accidents, whether the average goes up or down is totally beside the point'. 'But Height Kills' bellowed the Councillor, 'no it doesn't' the engineer bellowed back, of course he should have said 'not necessarily' but this is not an easy thing to bellow.
'How can you say height didn't cause this?' Councillor Prescott produced a press photo of the mangled remains of a double decker wedged under the Railway Terrace bridge and dropped it on the desk with the air of one producing the ace of trumps. 'The point was that the height was excessive for the situation, it is excessive height that causes the problem, not height itself' the engineer protested, but the Councillor wasn't listening, 'I've already decided to introduce a height reduction program, reducing all existing height limits by a foot, if this succeeds in reducing heights, I'll introduce a host of new height limits, if it doesn't I'll reduce the limits further until it does....'
The engineer stopped listening; once Councillor Prescott had made up his mind, there was no point in giving him the facts.
By Andrew Bent
The traffic engineer was quite pleased with himself, he had finally managed to stop the local bus drivers trying to take their double deckers under the low bridge under the railway, so Councillor Prescott might finally concede that he knew what he was doing. But as he entered Prescott's office he saw that the councillor was in an ominously thoughtful mood.
'I see we've had a reduction in accidents in Railway Terrace' said Mr Prescott, 'Yes' said the engineer, anxious to demonstrate his success, 'You see I did a survey and found that the maximum safe height under the bridge was 12'2", so I arranged for some warning signs to stop anyone taking a vehicle more than 12' high...'
But the Councillor had already lost interest. 'I've been studying some statistics' said the Councillor (the engineer winced, Councillor Prescott's grasp of mathematics was notoriously shaky) 'and it seems that when those new warning signs went up the average height of vehicles using Railway Terrace fell by 9 inches', 'Well, yes..' replied the engineer, 'and accidents dropped by 18%' continued the Councillor triumphantly'. The traffic engineer tried to figure out where this was leading, 'Do you realise what this means? Every inch of average height reduction leads to a 2% reduction in accidents! All we have to do is alter the warning signs to read 11' and accidents will drop by another 24%!'
His head spinning, the traffic engineer tried to reason with the Councillor, 'but if a 12 foot vehicle can get through perfectly safely, what is the point in imposing extra restrictions?' Councillor Prescott was having none of this, 'you don't seem to understand, Height Kills, if every inch of height reduction causes a 2% drop in accidents, surely we must have a height limit reduction program, let's speak to the bus company and see if they can lower the single deckers somehow.'
The traffic engineer thought quickly, there was no point in trying to explain the facts, Councillor Prescott always regarded knowledge of road traffic and accident causation a fatal disqualification for making decisions on the subject, but there was a possible way to turn the situation to advantage. 'There is another low bridge, under the disused railway in Beeching Close, where lorries do sometimes get stuck, but I haven't had the funds to tackle the problem before, I suggest that should be the first priority for the height reduction program'. Councillor Prescott agreed and the traffic engineer set off for Beeching Close with measuring rod in hand.
At first it wasn't clear why there was a problem at this particular bridge, there was already a height restriction of 7 feet, so why on earth were drivers ignoring it? After an examination of the bridge the reason became clear, the maximum safe height was over 14 feet. On receiving a recommendation that the 7 foot height limit was unrealistic and should be raised, Councillor Prescott was apoplectic, 'lorries are getting stuck because they are too high' he yelled, 'surely the limit needs to be lowered'. The engineer tried to point out that it was precisely because the limit was obviously ludicrous that it was being ignored, and that raising the limit would increase compliance, but the Councillor did not understand. 'In Railway Terrace, reducing the height reduced accidents, therefore Height Kills' he argued, 'surely raising the limit in Beeching Close will increase average heights, therefore increase accidents,' 'But it isn't the average height that matters' the engineer tried to point out, 'a 14 foot limit will be taken seriously and will reduce instances of excessive height, therefore reduce accidents, whether the average goes up or down is totally beside the point'. 'But Height Kills' bellowed the Councillor, 'no it doesn't' the engineer bellowed back, of course he should have said 'not necessarily' but this is not an easy thing to bellow.
'How can you say height didn't cause this?' Councillor Prescott produced a press photo of the mangled remains of a double decker wedged under the Railway Terrace bridge and dropped it on the desk with the air of one producing the ace of trumps. 'The point was that the height was excessive for the situation, it is excessive height that causes the problem, not height itself' the engineer protested, but the Councillor wasn't listening, 'I've already decided to introduce a height reduction program, reducing all existing height limits by a foot, if this succeeds in reducing heights, I'll introduce a host of new height limits, if it doesn't I'll reduce the limits further until it does....'
The engineer stopped listening; once Councillor Prescott had made up his mind, there was no point in giving him the facts.