Thousands worldwide are killed each day
in road accidents.
About 700 are child pedestrians, most of them just trying to cross
The main purpose of this website is to minimise these figures. It presents innovative ways to do so based on rectifying visual errors by drivers and pedestrians.
Trained as a civil and mechanical engineer, I became traffic
engineer for a regional council. Given the remit to analyse
and prevent road accidents, my suspicion that many involved visual error introduced me to a fascinating
interface between engineering and psychology that was largely
Creating products based on patents for visual innovations enabled me to become an independent road safety consultant and to develop ideas that led to a doctorate in psychology at Aberdeen University. This unusual professional mix has produced significant advances in understanding why road accidents occur and how to prevent them.
I identified such errors as prime causes of road accidents in the course of research carried out since the 1970s. They are documented in several papers, notably those linked to this page. By bringing them together I hope to encourage further development and application, because the huge potential for making roads safer, especially for pedestrians, is largely untapped. Initially, however, my focus was on accidents at rural bends.
I had noticed that as clusters of accidents developed on accident
maps, anomalies became apparent. One was that sharp bends often had
fewer accidents than gentler ones on the same road, leading to the
discovery that the shape of a bend rather than its severity could
determine its accident rate.
The reason is that a flaw in bend design causes drivers to misjudge the curvature of a bend, maintain excessive speed, and crash. Why this occurs, and how it could easily be rectified, is the theme of the paper "The case of the left-hand bend". Confirmation is provided in “A remedy for accidents at bends”.
Child's-eye view through original guardrail....
That insight into the importance of perception led to another
discovery. Although pedestrian guardrails significantly reduce
accidents, their benefit is reduced if they block visibility, especially for children. The scale of this problem in Britain could explain why we used to have the worst record in Europe for deaths and injuries to child pedestrians.
....then after replacement by Visiflex®
No guardrail provided satisfactory visibility so I invented one that did. In its original form, Visirail®, it became the most widely used in Britain because its casualty savings were so great. Early research and development is covered in the paper “Pedestrian guardrails and accidents”.
While it is obvious that improving visibility is
beneficial, why high-visibility guardrails reduce accidents by as much as 80% was
more puzzling. Seeking an explanation, I identified another
visual hazard. Pedestrians frequently cross streets
diagonally, but doing so can make them blind to traffic from one
side. Accident analysis affirmed that this is a key
factor in the majority of pedestrian accidents.
The reason that high-visibility guardrails prevent most accidents, therefore, is that they discourage diagonal crossing, as discussed in “A clearer vision for pedestrian guardrails”. This paper presents further development in guardrail design, culminating in the replacement of Visirail by Visiflex®. It also challenges the naïve claim that removing guardrails will reduce casualties because pedestrians will be more careful. This is nonsense, as can readily be demonstrated. Casualties would escalate by up to 400%, depending on type of guardrail. See "Guardrail Debate".
Research findings from my 1988 and 2007 papers clarify how best to use guardrails to prevent casualties. Design procedures are proposed in “Creating Safer Streets”. Any feedback on their use and effect would be welcome, to firstname.lastname@example.org.
Child pedestrians are not at risk only because of concealment, of
course. A more subtle visual error by drivers could be the principal
cause of collision with children.
That line of enquiry took me into the fascinating world of optic flow, the perceived motion of objects as an observer moves relative to them. Computer simulation at Aberdeen University revealed how our innate ability to interpret optic flow gives automatic warning of impending collision, but is unreliable for drivers. They have to rely instead on judgment of distance, but this is distorted by a visual illusion. Drivers tend to perceive child pedestrians as taller people, further away, which delays braking and increases risk.
The paper “Misperception of time-to-collision by drivers in pedestrian accidents” presents this hypothesis, shows that it causes more than half of all child pedestrian casualties, and suggests remedies. A review of the paper in New Scientist, “Deadly illusion brings death on the roads”, is an easy introduction.
More information about this research and its application is provided by my doctoral thesis "Safety implications of driver misperception in road accidents involving child pedestrians".
I have become convinced that visual errors are a critical factor
in most road accidents. Few road users or highway
professionals are aware of them, however, so there is neither public
concern nor government action to resolve
A further problem is that officialdom tends to lack enthusiasm for research that is liable to expose mistakes. So although the hazards highlighted in this website have been aggravated by errors and omissions in British design codes, these have not been rectified.
Equally irresponsible is the current trend to give precedence to architectural fashion over accident prevention, such as removing guardrails to prettify streets. Failure to check such absurd proposals by rigorous safety audits highlights the chronic need for a national research body empowered to investigate and improve road safety, as exemplified by the original Road Research Laboratory.
To close on a lighter note, pedestrians may avoid road accidents by switching to alternative modes of travel. Regrettably one which I developed ("Mountain Sailing"), although fast, free and carbon-neutral has yet to pass a safety audit.
The difficulties of working as an independent researcher were
greatly alleviated by my association with Aberdeen University.
Their encouragement to pursue radical research is much appreciated.
The backing of my patent licensees Hugh Logan and Danny Mackay has
also been invaluable.
Above all, “the Lord was my support. He brought me out into a spacious place”. His input to my work has been extraordinary, as outlined in "The Light in the Tunnel".