APRIL- MAY 2022
How to cure tunnel vision PCM treatments are used to reduce crash risk by improving driver speed behaviour, alertness and lane discipline within tunnels
T
he purpose of the study was to investigate and evaluate the application of low-cost perceptual countermeasure (PCM) treatments in tunnel environments as a means of improving driver speed behaviour and lane discipline within tunnels, thereby reducing crash risk. The project involved a systematic literature review and stakeholder consultation and an experimental study conducted in a virtual reality driving simulator. The review identified 33 PCM treatments that had been demonstrated as having a behavioural effect on driver speed behaviour and/or lane discipline. Stakeholder consultation complemented the literature review in outlining the
advantages/disadvantages of these PCMs, particularly in terms of ease of implementation, cost, maintenance, and applicability to a tunnel environment. Based on the outputs of the literature review and stakeholder consultations, three PCM treatments were selected for evaluation in the virtual reality driving simulator – a striped wall pattern, rumble strips (Edgeline and Centreline), and Pacemaker Lighting. The experimental study, involving 102 participants, conducted in a virtual reality driving simulator was designed to investigate whether the application of PCM treatments had any impact on drivers’ speed or lateral control in road tunnels and to determine what
drivers’ opinions were of the proposed PCM treatments. The findings revealed that, as implemented in the simulated tunnel environment, the three PCM treatments evaluated had little or no positive effect in either maintaining drivers’ speed or lane position in the simulated tunnel environment. This does not mean, however, that they were ineffective as treatments, given that there is previous evidence which demonstrates that one of the treatments (Pacemaker lighting) has been found to be effective in a real tunnel environment, and that rumble strips are effective on real open roads. Further research is recommended to determine whether certain critical pro-
posed modifications to the experimental design utilised in this study would make these PCMs more effective in inducing positive changes in driving behaviour in the virtual tunnel environment. Subjective feedback from study participants indicated that none of the PCMs evaluated were perceived to compromise their safety. On the contrary, evidence from this study indicates that the tunnels treated with PCMs were rated as being significantly more visually interesting, more attractive, induced less boredom and less sleepiness (striped wall patterns), and were significantly more memorable (Pacemaker lighting), compared to the untreated tunnels.
Sidewall striped patterns
preliminary evidence of the efficacy of installing wide to thin stripes along a tunnel wall in reducing speed although this finding has yet to be replicated. Across the ratings, the stakeholders indicated that this was a mid-range treatment with respect to modifying speed. The cost and maintenance associated with this treatment might be high
depending on how it is implemented. It was deemed suitable for a tunnel environment. Additional comments from the stakeholders suggested
that considerations would need to be made regarding the painting and cleaning of the tunnel walls with this treatment.
A single simulator study by Manser and Hancock (2007) found that when drivers were exposed to wide to thin stripes on a tunnel wall, they reduced their travelling speed. This effect was further attenuated when the stripes on the wall had texture added to them. This finding provides 40 infrastructurenews.co.nz
