Prevent or Punish: JJ Leeming

Sherlock Holmes’ quick eye took in my occupation (with the red-haired man, writes Dr Watson), and he shook his head with a smile as he noticed my questioning glances. “Beyond the obvious facts that he has at some time done manual labour, that he takes snuff, that he is a Freemason, that he has been in China, and that he has done a considerable amount of writing lately, I can deduce nothing else.”
Mr. Jabez Wilson started up in his chair, with his forefinger upon the paper, but his eyes upon my companion.
“How, in the name of good-fortune, did you know all that, Mr. Holmes?”

Holmes’s powers of observation were always a surprise.

“Your hands, my dear sir. Your right hand is quite a size larger than your left. You have worked with it, and the muscles are more developed.”
“Well, the snuff, then, and the Freemasonry?”
“I won’t insult your intelligence by telling you how I read that, especially as, rather against the strict rules of your order, you use an arc-and-compass breastpin.”
“Ah, of course, I forgot that. But the writing?”
“What else can be indicated by that right cuff so very shiny for five inches, and the left one with the smooth patch near the elbow where you rest it upon the desk?”
“Well, but China?”
“The fish that you have tattooed immediately above your right wrist could only have been done in China. I have made a small study of tattoo marks and have even contributed to the literature of the subject. That trick of staining the fishes’ scales of a delicate pink is quite peculiar to China. When, in addition, I see a Chinese coin hanging from your watch-chain, the matter becomes even more simple.”
Mr. Jabez Wilson laughed heavily. “Well, I never!” said he. “I thought at first that you had done something clever, but I see that there was nothing in it after all.”

Holmes was put out. He knew his scrutiny was acute and that, as often as not, it provided information overlooked by the most studious. Deep knowledge relieved him of the tedium of prejudice – pre-judgement on the basis of received wisdom or faulty logic. “I begin to think, Watson,” said Holmes, “that I make a mistake in explaining. ‘Omne ignotum pro magnifico,’ you know, and my poor little reputation, such as it is, will suffer shipwreck if I am so candid.”

JJ Leeming was in the Holmesian mould. He would have agreed that “Omne ignotum pro magnifico - every unknown thing is taken for great,” by those who knew no better. He was ruled by observation, logic and working under Lt-Col G T Bennett, the County Surveyor of Oxfordshire, was among the first to apply them to a study of road accidents, Bennett realised that the established view — even in the 1930s — about the culpability of drivers for accidents was not based on the facts. Such was no more acceptable then, than today. The only people who took any notice were other traffic engineers. Malcolm Heymer reviewed JJ Leeming’s 1969 book Road Accidents, Prevent or Punish for the Association of British Drivers (ABD). My copy, about which I wrote at the time, I fear was lost in my last move. I thought everyone had forgotten the great engineer. Fortunately the ABD has not and Leeming should be read by anyone with an open mind on road safety.

Leeming was County Surveyor of Dorset, believing that road accidents should be analysed critically and dispassionately. His conclusions, like those of Holmes in the view of Mr Jones of Scotland Yard, were viewed with suspicion. “You may place considerable confidence in Mr. Holmes, sir,” said the police agent loftily. “He has his own little methods, which are, if he won’t mind my saying so, just a little too theoretical and fantastic, but he has the makings of a detective in him. It is not too much to say that once or twice, as in that business of the Sholto murder and the Agra treasure, he has been more nearly correct than the official force.”

The great detective had an exact opinion of Mr Jones: “He is not a bad fellow, though an absolute imbecile in his profession.” In the view of Establishment Jones’s, accidents were caused by the wilful misdeeds of drivers, who must be punished. Leeming knew that this culture of blame led to making true contributory factors difficult to establish. Jumping to conclusions, he claimed, resulted in failures to address real problems when he took over in Dorset.

He gave an example: “Two men left a public house. Although not actually drunk, the landlord thought they had had enough and did not think the driver incapable. They drove a few miles to Warmwell Cross, where the driver, paying no attention to a Halt sign, collided with a lorry. Both men were killed.”

Most people would ascribe the accident to drink-driving and give it no further thought. Leeming decided that a traffic engineer had to establish all factors, without ascribing blame. A factor, he said, was something that could have altered or prevented the accident and he identified five; Chance, Human Error, Road Layout, the Law, and Drink.

Chance: Obviously if the lorry had not been on the main road, the accident would not have happened, despite the car driver's Human Error. Road Layout: investigation into other accidents at the same place revealed what had already deceived drivers. The crossing lay over a crest and although a stop line and HALT markings were painted on the road, the incline made them virtually invisible to approaching drivers. Anybody familiar with the area — Leeming and his staff — knew the junction, so never had to rely on spotting the markings. Strangers were caught out, sometimes fatally. Law: Leeming included this for two reasons. Firstly the regulations concerning Halt signs at that time meant that they were not placed at the junction itself, nor did they tell drivers the distance to the junction. Secondly, and more important, was the pressure on police to charge drivers with offences — from failing to obey Halt signs to causing death by dangerous driving. This had prevented Leeming from discovering the trap earlier, so he organised an experiment involving police, to observe drivers’ behaviour. Those who failed to stop at the sign were pulled up and talked to Leeming's staff. Local press unfortunately ran a story complaining that erring drivers were going unpunished and the experiment was abandoned after a day, but not before drivers had provided vital clues about the invisibility of the sign. The junction was improved and there was a dramatic reduction in accidents.

Whether the collision would have happened had the driver not been drinking is anyone's guess but it showed how importent it was to look beyond the obvious.

Leeming had not been entirely immune from conclusions about driver blame. When he moved to Dorset in 1946 he assumed, like almost everybody, that skidding accidents were due to bad driving, dismissing claims about road surfaces as mere excuses. However, following complaints about a series of bends with a bad accident record, he examined the road surface, discovering that bitumen had risen to the top, covering the aggregate, so it became slippery when wet. Although still unconvinced, he had the surplus material planed off. The accidents stopped. Even then he thought it an isolated case.

Another incident convinced him. There were complaints about skidding on asphalt surfaces laid by new machines. The materials used weren’t new, the method of laying was. Leeming assumed the skids were due to bad driving, but when they became frequent he investigated: “I discussed it with a senior member of the police. He dismissed it all with a remark, ‘good drivers don't skid’. Later I received a phone call from another policeman, who said I must do something about the surface. One of their cars had skidded and was a write-off. I could not resist murmuring that good drivers don't skid, and it was not well received. Even the police are human; he had not heard what his colleague had said.” Further examination of the road surface showed, once again, how the bitumen had risen to the top due to a vibration bar fitted to the new machines. A reduction in the bitumen content of the mix cured the problem. Leeming found other counties with similar problems so began experimenting with surface dressing on sharp bends with poor accident records. The results were dramatic. His conversion was complete.

Leeming became a firm believer in not jumping to conclusions about the causes of accidents, or the value of accepted solutions, without a rigorous study of the facts. In his chapter on statistical methods, he quotes G K Chesterton: “A man of science isn’t trying to prove anything. He’s trying to find out what will prove itself.” Leeming was always meticulous about including all results and data available on any issue he was investigating, even if some of the data pointed in a different direction from the rest.

As we know only too well, many reports on road safety (and other) issues have started with an assumed conclusion, and data has been selected to fit a conclusion. Leeming was scathing about propagandists who misused statistics by comparing different things and hoping people did not notice that they were being duped.

Nothing to do with safety really but a nice picture. Number one daughter at Le Mans, 1930s.