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Effect of Improving the Visibility of the Traffic Path on Vehicles Speeds and Safety at Work Zones
- Author / Creator
- Ahmed, Mohammed N S
Because of the documented mobility issues and safety risks associated with work zones, extra attention is required when designing the layout of traffic control devices. Current traffic accommodation guidelines at work zones have certain limitations that potentially cause driver confusion and is often ineffective at reducing speeds. This study conducted a comprehensive review of frequent safety problems around work zones to identify common types of collisions and the major factors contributing to collision occurrences. The study then outlined different combinations of highly reflective and visible intervention materials from 3M Canada that were implemented at several work zones. These intervention materials, such as temporary reflective tape, removable black mask, and other fluorescent and highly reflective materials, were used to better demarcate the desired traffic paths for drivers as they passed through work zones. Finally, the impact of these interventions on traffic safety was evaluated in order to understand the relationship between improving the visibility of the traffic path and vehicle speed at work zones.
Prior studies indicate that speeding and inefficient traffic control devices are the main factors impacting safety around work zones. Therefore, a particular aim of this project was to evaluate the impact of 3M intervention materials in different combinations on vehicle speed through work zones. To do so, the study monitored before and after speeds at nine construction sites in the City of Edmonton (COE) during the summer months of 2019. These treatment sites were chosen in collaboration with COE’s Traffic Operations group. Sites were also chosen as controls to account for confounding factors in the before and after analysis. This represents an experimental, observational study design to assess the effect of work zone interventions on driver speeds.
The results showed that increasing the visibility of the traffic path at work zones using the combinations of 3M high reflective and visible products led to significant vehicle speed reductions at the treatment sites that ranged between 4.7 to 11.6 km/h. The effectiveness of the interventions was either unidirectional or bidirectional, depending on the placement of the interventions. In addition, an improvement in drivers’ speed limit compliance was observed in the ‘after’ period. Furthermore, the outcomes showed that observed vehicle speed reductions during working hours were higher than the values in non-working hours. A traffic conflict analysis revealed that there were no near misses or accidents during the test period, further indicating that the installed intervention materials did not cause any traffic issues or conflicts. Results found in this study can greatly assist traffic safety agencies to optimize the use of traffic intervention materials at work zones and provide more details about the effective use of the reflective control devices.
- Graduation date
- Fall 2020
- Type of Item
- Master of Science
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