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AGENCY TESTIMONY
Findings from DOT's daylighting safety performance study
0:28:07
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129 sec
Eric Beaton presents the findings from DOT's recent study on daylighting safety performance, which was conducted in response to Local Law 66 of 2023. The study reveals that while daylighting can be a useful tool, it is not a one-size-fits-all solution and may have unexpected effects on safety.
- The study found that hardened daylighting with physical infrastructure enhances safety
- Side-only daylighting showed no statistically discernible effect on safety
- Locations with restricted parking for non-traffic safety reasons correlated with higher injury rates
- The study compared data from 756 daylighted locations and nearly 8,000 historically daylighted locations
Eric Beaton
0:28:07
While widely discussed, daylighting is surprisingly poorly studied in terms of its actual effect on safety.
0:28:14
As promising as daylighting is in concept, the chair was right to require an in-depth study of the benefits of this treatment in local law sixty six of twenty twenty three.
0:28:24
Pursuant to that law, DOT recently released the first of its kind study of daylighting safety performance.
0:28:31
The study found that while daylighting is a useful tool when used properly, it is not a one size fits all solution and that indiscriminate daylighting could actually have negative effects on safety.
0:28:43
The study also found that hardened daylighting with physical infrastructure installed to prevent vehicles from occupying that space does enhance safety but that other safety interventions can also have equal or greater safety improvements.
0:28:59
The results of the study were surprising even to us but speak to the importance of doing good analysis and then being willing to update our beliefs based on what we find.
0:29:09
As part of this study, we did a few things.
0:29:12
First, we reached out to cities across the country, large and small, to see if there had ever been a real analysis of daylighting effects.
0:29:20
And we found no study that had ever looked at the effects on injuries.
0:29:24
Second, we looked at the effects before and after daylighting implementation at seven fifty six locations from 2019 to 2021 comparing against other similar intersections to account for the effects of the pandemic.
0:29:40
This effort found that hardened daylighting contributed to statistically significant injury reductions, but that side only daylighting had no statistically discernible effect.
0:29:50
Finally, we looked at nearly 8,000 locations that were daylighted historically for non traffic safety reasons such as fire hydrants and bus stops and compared again to other nearby intersections.
0:30:03
This comparison found that locations with this restricted parking were correlated with statistically significant higher rates of injuries, which held even as we looked across different geographies and different types of intersections.