Evaluating the Impact of Improved Roadway Lighting on Nighttime Driver Behavior and Pedestrian Safety
Project Description
Nighttime crashes involving pedestrians and bicyclists remain a significant safety concern, with 76% of pedestrian fatalities occurring in low-light conditions. Insufficient roadway lighting exacerbates visibility challenges, increasing crash risks for vulnerable road users (VRUs). Research indicates that enhancing street lighting can reduce pedestrian injuries by up to 50%; however, many urban corridors remain inadequately lit, leaving pedestrians and cyclists at heightened risk.
While improved roadway lighting is widely recognized as a potential countermeasure to enhance safety, existing studies rely primarily on crash data, which often lack the granularity needed to isolate its direct safety effects. Despite its intuitive benefits, empirical evidence quantifying the real-world safety impacts of lighting improvements remains limited. Understanding how enhanced lighting influences crash rates, driver behavior, and pedestrian perceptions is essential for guiding infrastructure investments and policy decisions.
This study aims to evaluate the safety effects of improved roadway lighting by analyzing changes in nighttime crash rates, driver behavior, and pedestrian perceptions. With support from the City of Milwaukee, corridors within the Pedestrian High-Injury Network (HIN) will be identified as study sites. Using a before-and-after observational study design combined with surveys, this research will examine the relationship between enhanced street lighting and safety outcomes for VRUs.
The research seeks to answer the following questions:
How does improved roadway lighting impact VRU nighttime safety?
Diminishing returns effect: Does the initial reduction in nighttime crashes decline over time as behavioral adaptation and other risk factors emerge?
Spillover effect: Do safety benefits extend beyond the treated area, or does the intervention inadvertently shift risk to other locations or behaviors?
What behavioral changes occur among drivers and VRUs in response to improved lighting?
How do road users perceive the effectiveness of increased roadway lighting in terms of safety and comfort?
By addressing these questions, this study will generate data-driven insights into the role of roadway lighting in improving nighttime safety. Findings will inform policy and infrastructure decisions while supporting Milwaukee and other cities in their efforts to create safer, more accessible urban environments for VRUs.
Outputs
Both quantitative and qualitative analyses under the before-and-after observational study framework will be performed. This study will compare treatment sites (where lighting improvements occur) and control sites (similar locations without changes) to assess the impact of lighting enhancements on nighttime safety.
Quantitative Analysis
Illuminance measurement: compare before and after the roadway lighting improvement projects.
Crash Data Analysis (where available): Compare nighttime crash rates, severity, and crash types before and after lighting improvements. Given the short evaluation period, surrogate safety measures will supplement crash data.
Behavioral Analysis:
Driver behavior: Assess vehicle speeds and yielding compliance at pedestrian crossings using radar speed detectors and manual observations.
Pedestrian behavior: Observe crossing compliance, midblock crossings, and gap acceptance to evaluate changes in risk-taking behavior.
Surrogate Safety Measures (examples may or may not include):
Conflict analysis (where feasible): Identify near-miss incidents through field-based observations.
Post-encroachment time (PET): Measure pedestrian-vehicle interaction gaps to assess potential safety risks.
Pedestrian hesitation/delay: Evaluate whether improved lighting reduces pedestrian hesitation before crossing.
Qualitative Analysis
Public Perception Survey:
Signs with QR codes will be placed near study sites to collect driver and pedestrian feedback on visibility, safety perceptions, and behavioral changes.
Survey responses will be analyzed to determine whether perceptions align with observed behavioral changes.
Data Feasibility Considerations
Crash data: Availability depends on reporting timelines; short-term impacts will rely on behavioral and surrogate safety measures.
Speed and yielding data: Feasible using existing traffic sensors, radar detectors, or manual field observations.
Conflict and pedestrian behavior data: If video-based analysis is unavailable, trained field observers will document interactions.
By integrating illuminance data, crash data, behavioral observations, and public perceptions, this study will generate data-driven insights to assess the safety effects of improved roadway lighting.
Outcomes/Impacts
This study will generate actionable insights into the safety effects of improved roadway lighting, contributing to data-driven decision-making for urban transportation safety. The key deliverables and outcomes include:
Comprehensive Technical Report
A detailed analysis of the safety impacts of improved roadway lighting, incorporating crash data (where available), behavioral observations, and surrogate safety measures.
Evaluation of the before-and-after effect on driver and pedestrian behavior, highlighting key findings from both quantitative and qualitative analyses.
Data-Driven Recommendations for Policymakers and Transportation Agencies
Practical guidelines for lighting investments based on empirical findings.
Insights into optimal lighting strategies for enhancing pedestrian and bicyclist safety in urban environments, particularly for high-risk corridors like those within the Pedestrian High-Injury Network (HIN).
Presentation Materials for Outreach and Stakeholder Engagement
Tailored presentations and visual data summaries to communicate findings to local agencies, city planners, and community stakeholders.
Engagement materials to support decision-making for future infrastructure improvements.
Survey Insights for Human-Centered Safety Improvements
Public perception data on how lighting improvements affect nighttime travel comfort and perceived safety.
Identification of potential unintended consequences such as spillover effects or diminishing returns over time.
Policy Contributions to Vision Zero and Proactive Safety Strategies
Evidence-based support for Vision Zero initiatives by demonstrating how lighting improvements align with pedestrian and bicyclist safety goals.
Potential recommendations for integrating lighting enhancements into broader urban safety planning to reduce nighttime crashes and improve overall road safety.
By delivering these outputs, this study will provide critical insights to help cities like Milwaukee make informed decisions on roadway lighting improvements to enhance nighttime safety for VRUs.
Dates
12/1/2025 to 11/30/2026
Universities
University of Wisconsin Milwaukee
Principal Investigator
Yang Li
yangli22@uwm.edu
https://orcid.org/0000-0001-5358-7835
Project Partners
City of Milwaukee
Research Project Funding
Federal: $60,005
Non-Federal: $29,999
Contract Number
69A3552348336
Project Number
25UWM02
Research Priority
Promoting Safety