Designers Neglect the Driver
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Research Workers Criticize Layout of Vehicles : Eight Problems Requiring Research Examined at Conference: £2,000m. Spent on Road Transport in 1954 VEHICLE, designers were this week accused of concentrating entirely on mechanical features and neglecting the driver.. Faults in vehicles militating against safety and convenience in driving were listed under seven main headings. "Why is the man regarded as so unimportant?" a.doctor asked.
The critics were speakers in a symposium on "Human Factors in Road Transport," organized by the Ergonomics Research Society and held at Bristol University. It opened on Monday evening and closed yesterday. It was designed to bring together specialists and research workers in engineering, science, medicine, motoring and transport.
The great research effort needed to raise efficiency in road transport and to promote safety at higher speeds was emphasized. Eight problems requiring research were outlined and the American approach to the problem of making the vehicle fit the driver was explained.
Problems Requiring Research •
IN presenting the opening paper, Mr. 1G. Grime (Harmondsworth) said that it was estimated that in 1954 nearly £2,000m. was spent on the transport of goods and passengers by road. This represented about a tenth of the country's total expenditure, and was about four times greater than expenditure on rail transport.
Road accidents alone were calculated to cost over £75m. a year and to result in about 5,000 deaths and 250,000 casualties. " The . r oad transport business will thus repay a very large research effort to improve its efficiency and to promote safer operation at higher, speeds," he said.
In presenting the following list of problems on which research was required, Mr. Grime emphasized the importance of studying night traffic conditions in towns:— (I) New lighting systems, such as polarized light; glare, and visibility under adverse conditions.
(2) Street-lighting installations, particularly as regards the influence on vision of the pattern of light and shade on the road surface.
(3) The general design of vehicles to give the best visibility by day and night.
(4) Signalling devices, traffic signs and road markings, particularly in towns.
(5) Simplification of driving controls.
(6) Design of roads to reduce monotony, as well as the seating, springing, noise, vibration, temperature and humidity of vehicles.
(7) Protection of occupants of vehicles.
Designing Vehicles to Fit Drivers.
FOR six years, Harvard School of 1 Public Health has been conducting extensive research into the designof vehicles to fit the drivers, with the object of improving operational efficiency and safety, Mr. Ross A. McFarland (Boston) said that precise measurements Were made of the driver's area of lorries and buses, and body measurements of -about 400 drivers were taken. The two sets of data were correlated, and applied to practical situations. Drivers at Work were studied.
"Thirteen truck and nine bus models were evaluated in relation to (I) fixed limits of the working spacc, (2) human sizing, (3) seating, (4) controls, (5) visibility from the cab, and (6) instrument panels and switches," said Mr. McFarland. "Many 'design errors' were found in relation to sizing requirements and insufficient adjustability of the seat was common.
"Visibility, especially to the side and rear, was a serious problem. Controls, in a number of instances, were poorly located for ease of operation, and in some models the instruments could not be read from the usual driving position."
A mock-up cab was devised, permitting nine different adjustments of the seat, steering wheel and foot controls. Fewest errors were made when subjects were allowed to find the combined setting of the adjustments which was most comfortable for them individually.
An " activity " analysis of bus driving was made, operating errors made by drivers in routine bus work were analysed, eye movements of drivers were studied, and critical incidents and near-accidents on long-distance bus and lorry operations were examined.
Seven Common Faults in Vehicles
nR. W. F. Floyd (Department of 1--/ Physiology, Middlesex Hospital Medical School), took up Mr. McFarland's theme and listed seven inadequacies in the design of vehicles which affected operation and control. Common faults were:—
• (1) Pedals and levers often out of reach of more than 5-10 per cent. of the population; (2) controls wrongly or badly placed for safe operation; (3) controls too heavy in operation; (4) seat adjustment insufficient and the posture of the driver unsatisfactory; (5) working space for the driver inadequate; (6) restricted vision to the front, sides or rear; (7) instruments not easily visible.
These defects probably resulted from design engineers not having precise and adequate information on the shape, size and capabilities of human. beings. Eye position should be the critical factor in determining design. The . position and design of the steering wheel and pedals should rank next in importance.
Dr. Floyd criticized the high temperatures in some commercial vehicles. When the ideal vehicle had been designed in the manner which he recom. mended, it would, he said, be necessary to test a prototype by means of a biological trial. Measurements and tests on' driver behaviour would have to be studied.
".Such a procedure has probably never been used by the motor industry in this country, but the counterpart mechanical trial is carried out with the utmost thoroughness by every leading manufacturer on every new model before production." said Dr. Floyd. "Why is the man regarded as so unimportant in this man-machine relationship?"
What Causes Fatigue?
DRIVING was not physically exhausting and was, technically, fairly simple. There were, however, factors which induced fatigue, said Mr. H. Y. Groenewegen (Utrecht), who mentioned that the Netherlands Driving Time Act stipulated a maximum driving period of five hours without rest.
The constancy of the task of driving and the position of the body made for monotony and fatigue, and aggravating conditions were had weather, the boredom of a monotonous road, variation in sunlight and shadow, and "individual displeasure with other road users."
Fatigue factors of individual vehicle designs were not of great importance to private motorists, but could be serious to professional drivers. General health and mental disposition of drivers were important. People should not be allowed to drive when fatigued by a bad night's sleep, or distracted . by personal worries.
Drivers ought to know the signs of over-fatigue, such as ideas that there watt something wrong with the vehicle. that it was slowing down, was difficult lo drive or was making more noise than usual. With increasing fatigue it became harder to steer a true course and the vehicle seemed to pull to the left or right.
A motive, such as the desire for overtime pay, could make a driver continue when he had reached a state of fatigue, but the accident risk was clearly higher. Sleepiness was personal and a driver alone was responsible. for whatever accident -might occur, Employers were nevertheless responsible arid should not press men to obey excessive demands.
How Driving Taxes Energy
ASSUMING that a heavy-lorry driver covers -1,100 miles a week at 25 m.p.h., his energy expenditure at work would be 7,392 calories, compared with 5.710 for a clerk and 11,870 for a miner, said Mr. 3. G. Fletcher (Hampstead), who detailed the muscle output required its driving various vehicles.
Six persons drove different vehicles and their average calory output was found. Driving a car involved an outPLO of 2.24 calories a minute, a 1-ton lorry 3.16, a heavy motorcycle 3.39. and a fork-lift truck 3.92.– Traffic conditions altered energy expenditure,and driving a small car absorbed more energy than driving a more powerful car under comparable conditions. Value's varied from 1.42 calories a minute in driving a large car on the open .road to 3.19 in driving a small car in a city centre during rush
hours.
Heavier Weights, Less Work
IF a vehicle was loaded with fairly heavy I individual units, less energy was spent by men in unloading than if the load comprised many more lighter units, indi-. cated Mr. E. A. Muller (Dortmund). He and three colleagues had investigated energy expenditure by men unloading stones from a vehicle and piling them. and found that if a load comprised 4-lb. stones, twice the amount of .energy was used as for .a load of 28-1b_ stones.
This was because fewer individual movements were involved in shifting the load of bigger stones. It was easiest to pick up a weight when it was between 1 ft. 6 in. and 3 ft. from the ground. Mr. Miller concluded that if big stones of low specific gravity, instead of normal bricks, were used for building. six men could be replaced by one.
Psychology to Reduce Accidents?
pSYCHO-TECHNICAL examinations of drivers had reduced accidents in Belgium, claimed Mr. R. Beirlaen• (Brussels)-.. Over two years ago, the Touring Secours Organization estab
fished a centre for psychological consultation for use by all vehicle drivers.
Its objects were ,(1) to show drivers their own capabilities, with a view to taking safety measures to compensate for possible deficiencies; (2) to select professional drivers in such a way that the averaee skill was higher, and those unsuited to driving were directed towards other trades; (.3) to advise people before starting to learn to drive; and (41 to help drivers Who had had many accidents to discover the reasons. as well as possible remedies.
Individuals who submitted themselves to the, lest had been helpedand accidents had been avoided, Mr.eBeirlaen said.
Reducing Injuries from Steering Columns
THE need for spreading the blow, or for redesigning the steering system to avoid severe injury to a driver by impact with the steering column in a serious 'accident, was emphasized by Mr. H. J. H. Starks (1-larmondsworth).
He also referred eo the importance of affording better protection for the occupants of vehicles, both by the provision of protective padding and by avoiding sharp projections, such as instrument knobs and other controls, .hard • seathacks, and so on.
How to Improve Visibility
DEALING with driving visibility, Mr. R. A. F. Fosberry (Nuneaton) said that even in daylight with clear conditions. the driver's view was restricted by the construction of the vehicle. An American method of. obtaining data before preparing suggested . minimum requirements, was to use two lamps placed to correspond with the average driver's eyes. Visibility was assessed. by the extent cif the shadows cast by body pillars, the -bonnet and the other obstructive parts.
New Experiments with Indicators
T-WCI new series of experiments 'with signals by the Road Research • Laboratory Were describedby Mr. A. Crawford (Harmondsworth). The first was to decide whether the semaphore direction indicator was as' effective as the high-intensity light signal, and whether the light signal, if it were chosen, should flash. The second series concerned the best position for the indicator on a vehicle in relation to the stop lights and headlights.
It was found that drivers responded most quickly to amber flashing indica-. . tors on door pillars. White indicators at the front and red indicator: -at the rear produced the 'slowest -reaction.
No firm conclusion had been reached on experiments to compare the relative merits of direction indicators illuminated by a steady light or by a flashing light of equal intensity. A rear indicator was found to become less effective as it was moved nearer to the stop light. An indicator was ,most effective when about 18 in. above the headlights.
.Coloured Beams to
Fight Dazzle
HE proposal made La long time ago
that the roads should be•iljuspinated by white light reconstituted by the :convergent'beams Of car 116adlights, complementary colours,' was mentioned by Mr. A. Wisner (France), when dealing with the problem of dale. With presefa limited techniques. he said; a coloured headlight could. -be Obtained only by filtration of part of _the 'White light emitted by 'the filament: A 'great deal of energy_ waS thus. wasted, .
It was possible that. one daY,, headlights would .he. made to emit in blue and yellciw.' When that time came the proposed solution of the dazzle problem might be more acceptable to engineers.
Better. Lights to' Cut Dazzle
QOME drivers are . dazzled because 1.--) their own headlights "are so poor that moderate glare discomforts them. The dazzle problem can -be substantially alleviated if deteriorated lamps are replaced or restored.
Mr. R. L. Moore (Harmondsworth) made this observation and contended that advances in headlamp design would confer fewer benefits than improvements in maintenance and the aim of existing equipment. .
One Headlight Sufficient
SPEAKING as an ophthalmologist. Mr'. B. Rosengren (Goteborg) had these observations to make on the solution of the glare problem:—
Dark glasses are of no use. A dark or non-transparent plate on the' windscreen may serve its purpose, but does not completely solve, the problem. Polarized light might be a possibility if universally applied, but this would be difficult to put into practice. Moreover. luminance would be much reduced. Yellow lights are not satisfactory. The nearest possibility seems to be a sharp demarcation of the cone of light from the headlamp. One headlight should be sufficient.
Effects of Vibration
MECHANICALLY, the human hod, was not a simple mass, but a damped system of masses and springs, said Mr. D. Dieckrnann (Dortmund), Who described the effects of vibrating people sitting or standing on a platform. The platform vibrated at frequencies of up to 100 cycles a second.
At five cycles a second the whole body oscillated at maximum resonance. The head showed additional resonances in a range of frequencies from 20-30 cycles a second.