Three university professors have suggested why people keep tripping over an 'optical illusion' cycle lane near Bristol. Psychology experts from Bristol and Cardiff universities visited Keynsham after months of complaints about the new lane and markings.
Professors Nick Scott-Samuel (University of Bristol), Ute Leonards (also Bristol) and Simon Rushton (Cardiff) are interested in the human visual system, so took time out to head to the High Street after reading about people who have injured themselves there.
Prof Scott-Samuel, whose field is experimental psychology, said the many media reports about the ‘optical illusion’ cycle lane piqued their interest. Having had a first-hand look, they identified various factors about the human visual systems which could factor into people falling in that area.
Read next: Work planned at 'optical illusion' street where people keep tripping over
Prof Scott-Samuels said their findings indicated that while the design of the cycle lane complies with current government guidance on cycle lane infrastructure, it does not take into account how the visual system works to guide movement, using processes such as depth perception. Between the road, the cycle lane and the kerb, the surface may look flat, but there are height differences.
They also found that: “Two common cues used by the human visual system to segment surfaces are how dark or light they are, and their surface appearance - how rough or smooth”. It is these variations which can signal edges.
They also said the layout of the cycle lane is inconsistent with regard to the outer and inner edges of the kerb. They said as a pedestrian sees a raised kerb on the far side of the cycle lane, this raises the expectation of a similar kerb on the near side of the cycle lane.
They added: “These expectations are fundamental when it comes to planning one's movements, as people look on average two paces ahead of where they are going to step. The cycle lane is about two steps wide, meaning people will look at the opposite side of the lane just before they step on the lane itself.”
They predicted that pedestrians are more likely to fall when they cross from the pavement. This would be because the step is obvious in one direction but not the other.
With regard to possible solutions, they said: “The best solution would be to put dropped kerbs on both sides of the cycle lane. An alternative, cheaper approach might be to add white lines to both sides.” They added that these solutions should help to reduce pedestrian confusion caused by the presence of different boundaries on either side of the cycle lane.
Read next: Bristol man falls foul of Keynsham's 'optical illusion' cycle lane
Keynsham’s High Street cycle lane opened in March 2022, following nine months of work to rejuvenate the town centre. Keynsham South councillor Alan Hale used a freedom of information (FOI) request in April, which revealed 59 people had sustained injuries by then since the new lane opened.
A spokesperson for Bath and North East Somerset Council said remedial works would be carried out on the High Street between June 5-24, but specifically to repair paving slabs and replace damaged bollards. After these works are completed a Stage 4 Road Safety Audit with regard to the cycle lane will follow.
Councillor Paul Roper, cabinet member for economic and cultural sustainable development said: “Alongside the audit, the council will undertake a design review over the summer to assess whether additional enhancement can be made to reduce trips and falls further.”
Read next:
