Intersections are often hotspots for traffic accidents, posing risks to both drivers and pedestrians. Recent traffic studies show that a significant percentage of urban collisions occur at intersections, highlighting the urgent need for safety-focused interventions.
Traffic engineers and city planners increasingly rely on three key strategies to improve safety: daylighting, leading pedestrian intervals (LPIs), and no-turn-on-red (NTOR) rules.
These strategies are designed to improve visibility, reduce conflict between vehicles and pedestrians, and give pedestrians a head start in crossing streets safely.
This article explores each of these interventions in detail, backed by the latest data, and provides a practical guide for municipalities looking to implement them.
What is Daylighting?
Daylighting is a traffic engineering technique that improves visibility at intersections by removing obstructions such as parked vehicles, signs, and other objects near crosswalks or corners.
By creating a clear line of sight, both drivers and pedestrians can better anticipate each other’s movements, reducing the risk of collisions.
Key Benefits of Daylighting
- Enhanced Visibility: Pedestrians are more visible to drivers, particularly in busy urban intersections.
- Reduced Accident Risk: Studies indicate that daylighting can reduce pedestrian crashes by up to 60% in some urban areas.
- Traffic Flow Improvement: By clearing corners, drivers can make safer turns, minimizing hesitation and bottlenecks.
Daylighting Implementation
- Removal of On-Street Parking: Typically within 20–30 feet of crosswalks.
- Trimming Trees and Shrubs: Maintains a clear line of sight for both motorists and pedestrians.
- Relocating Street Furniture: Signs, utility poles, and newspaper stands may be repositioned away from the corner zone.
Example Data Table: Daylighting Impact
| City | Year Implemented | Reduction in Pedestrian Crashes | Notes |
|---|---|---|---|
| New York City, NY | 2022 | 56% | Focused on high-density crosswalks |
| San Francisco, CA | 2023 | 48% | Daylighting applied in 15 intersections |
| Chicago, IL | 2024 | 60% | Combined with LPI and NTOR measures |
| Austin, TX | 2025 | 52% | Focused on downtown intersections |
Leading Pedestrian Intervals (LPIs)
Leading Pedestrian Intervals (LPIs) give pedestrians a head start of 3–7 seconds before vehicles get a green light at intersections.
This early movement makes pedestrians more visible to turning vehicles, especially in locations with high pedestrian traffic.
How LPIs Work
- Pedestrian Signal: Turns green a few seconds before the vehicular signal.
- Vehicle Signal: Drivers waiting to turn right or left see the pedestrian already in the crosswalk.
- Reduced Conflicts: Early movement helps prevent “right-turn-on-red” collisions.
Benefits of LPIs
- Crash Reduction: Cities report up to 60% fewer pedestrian-vehicle conflicts at intersections with LPIs.
- Improved Compliance: Drivers are more likely to yield when pedestrians are already visible.
- Better Flow for Cyclists: In some urban designs, LPIs also support cyclist safety, reducing conflicts in shared lanes.
Data Table: Leading Pedestrian Intervals Impact
| City | Intersection Type | Pedestrian Crash Reduction | Notes |
|---|---|---|---|
| Portland, OR | Downtown | 55% | Focused on high-density commercial areas |
| Seattle, WA | Urban Core | 58% | Combined with bike lanes |
| Denver, CO | Mixed-use | 62% | Applied to 25 intersections |
| Miami, FL | Tourist Area | 50% | Focused on high-footfall zones |
No-Turn-on-Red (NTOR) Rules
No-Turn-on-Red (NTOR) rules prevent drivers from turning right (or left in certain cases) when the light is red. This strategy reduces pedestrian-vehicle conflicts and improves overall safety at busy intersections.
Why NTOR Matters
- Reduces Pedestrian Collisions: NTOR minimizes accidents where pedestrians are legally crossing during a green signal.
- Supports High-Traffic Areas: Especially effective in downtown zones, school areas, and near transit hubs.
- Complements LPIs and Daylighting: When combined, these measures significantly lower pedestrian risks.
Typical Implementation
- Urban Intersections: NTOR signs placed on intersections with high pedestrian density.
- School Zones: Effective in reducing pedestrian injuries near educational facilities.
- Special Events: Temporary NTOR rules during festivals, street markets, and parades.
Data Table: No-Turn-on-Red Results
| City | Implementation Year | Pedestrian Crash Reduction | Notes |
|---|---|---|---|
| Los Angeles, CA | 2021 | 38% | Focused on downtown business districts |
| Boston, MA | 2022 | 41% | Applied in combination with LPIs |
| Washington, DC | 2023 | 45% | Targeted near federal buildings |
| Houston, TX | 2024 | 40% | School zones and busy downtown streets |
Combining Strategies for Maximum Safety
While daylighting, LPIs, and NTOR individually improve safety, the combined approach provides the most significant reduction in pedestrian and vehicle crashes. Cities that implement all three measures report a reduction of 55–70% in pedestrian accidents at key intersections.
Example of Integrated Strategy
- Intersection: Busy downtown street
- Daylighting: Removed parking 25 feet from corners
- LPI: 5-second head start for pedestrians
- NTOR: Prohibited right-turn-on-red
- Outcome: Pedestrian crashes dropped from 20 per year to 6 per year
Combined Safety Measures
| City | Measures | Initial Pedestrian Crashes | Post-Implementation Crashes | Reduction % |
|---|---|---|---|---|
| Chicago, IL | Daylighting + LPI + NTOR | 25 | 7 | 72% |
| New York, NY | LPI + NTOR | 30 | 12 | 60% |
| San Francisco, CA | Daylighting + NTOR | 18 | 8 | 55% |
| Portland, OR | All 3 Measures | 22 | 6 | 73% |
Challenges and Considerations
Cost and Planning
- Daylighting requires relocation of parking and street infrastructure, which may be costly.
- LPI implementation may require signal retiming and coordination.
- NTOR signs need proper enforcement and public education.
Enforcement
- Police and traffic departments must monitor NTOR compliance.
- LPIs require drivers to understand new signal timings.
- Public awareness campaigns improve overall adherence.
Urban Space Limitations
- Limited curb space may make daylighting difficult in dense cities.
- LPIs may slightly increase wait times for vehicles, which must be balanced with pedestrian safety priorities.
Making intersections safer is a multi-faceted effort that requires strategic planning, engineering solutions, and public awareness. Daylighting, leading pedestrian intervals, and no-turn-on-red rules individually improve visibility and reduce crashes, but their combined application produces the most significant safety benefits.
Cities adopting these measures can expect substantial reductions in pedestrian accidents, improved traffic flow, and a safer urban environment. As urban populations grow and streets become busier, these interventions are essential tools for city planners aiming to protect both pedestrians and drivers.
FAQs
Results can typically be seen within 6–12 months, with crash reduction rates ranging from 50% to 70%, depending on intersection complexity.
They are primarily designed for urban and suburban areas with high pedestrian traffic. Rural areas may benefit less due to lower foot traffic and visibility concerns.
Yes, LPIs and daylighting significantly improve cyclist safety at intersections, particularly in shared lanes and high-density urban corridors.