What is Vulnerable Road User Protection?

 Vulnerable Road User (VRU) Protection is a key component of vehicle safety standards and testing programs like Euro NCAP, focusing on reducing injuries to pedestrians, cyclists, and other non-motorized road users struck by vehicles. VRUs are considered "vulnerable" because they lack the protective structure of a vehicle, making them highly susceptible to severe injuries or fatalities in collisions. 

VRU protection evaluates both passive safety (vehicle design to minimize injury upon impact) and active safety (technologies like Autonomous Emergency Braking [AEB] to avoid collisions). This aspect of safety is increasingly emphasized in global regulations and consumer safety ratings due to rising urban populations and non-motorized transport. 

Below is a comprehensive explanation of VRU protection, its testing, standards, integration with systems like Tire Pressure Monitoring Systems (TPMS), and its role in Euro NCAP ratings.

What is Vulnerable Road User Protection?

Vulnerable Road Users (VRUs) include pedestrians, cyclists, motorcyclists, and other individuals exposed to traffic without a protective vehicle structure. VRU protection focuses on:

Passive Safety: Designing vehicle exteriors (e.g., hoods, bumpers) to reduce injury severity when a VRU is struck.

Active Safety: Implementing technologies like AEB and cyclist detection to prevent or mitigate collisions.

Objective: Minimize fatalities and injuries, particularly head, leg, and pelvis injuries, which are common in VRU crashes.

VRU protection is critical in urban areas, where pedestrians and cyclists account for a significant portion of road deaths. For example, the World Health Organization estimates that pedestrians and cyclists make up 26% of global road traffic deaths, with higher proportions in Europe and developing regions.

Key Components of VRU Protection

 1. Passive Safety Features

   - Vehicle Design:

     - Hoods: Softer, deformable hoods with clearance above the engine to absorb head impacts.

     - Bumpers: Rounded, energy-absorbing bumpers to reduce leg and knee injuries.

     - Windshields and A-Pillars: Designed to minimize head injury severity.

     - Pop-Up Hoods: Active systems that raise the hood upon detecting a pedestrian impact to increase clearance and reduce head injury risk.

   - Purpose: Mitigate injury severity by reducing the force of impact on VRUs, particularly to the head (most fatal) and legs (most common).

 2. Active Safety Technologies

Autonomous Emergency Braking (AEB):

     - Detects pedestrians and cyclists using cameras, radar, or lidar, automatically applying brakes to avoid or reduce collision speed.

     - Effective in scenarios like pedestrians crossing roads or cyclists riding alongside vehicles.

Cyclist Detection Systems: Advanced AEB systems tailored to detect cyclists, accounting for their speed and movement patterns.

   - Nighttime Detection: Emerging systems use infrared or enhanced cameras to detect VRUs in low-light conditions.

   - Warning Systems: Alerts drivers to VRU presence (e.g., blind-spot monitoring for cyclists).

   - Purpose: Prevent collisions or reduce impact speed, significantly lowering injury risk.

 3. Crash Scenarios Addressed

   - Pedestrian Crossing: A pedestrian steps into the vehicle’s path (e.g., at a crosswalk).

   - Cyclist Alongside: A cyclist rides parallel to the vehicle, at risk from turning or door-opening collisions.

   - Child Pedestrians: Children running into the road, requiring rapid detection and response.

   - Nighttime or Low-Visibility: VRUs in dark or foggy conditions, where visibility is limited.

VRU Protection in Euro NCAP Testing

Euro NCAP includes Vulnerable Road User Protection as one of its four rating categories, contributing 20% to the overall 1-to-5-star rating (alongside Adult Occupant Protection [40%], Child Occupant Protection [20%], and Safety Assist [20%]). 

VRU testing evaluates both passive and active safety measures to protect pedestrians and cyclists. Below are the key aspects of Euro NCAP’s VRU testing (based on 2025 protocols):

 1. Passive Safety Tests

Purpose: Assess how vehicle design minimizes injury to VRUs upon impact.

  Tests:

     - Head Impact Tests:

       - A head impactor (simulating adult and child heads) is fired at the hood, windshield, and A-pillars at 40 km/h (25 mph).

       - Measures Head Injury Criterion (HIC, <1,000 for low injury risk).

       - Tests multiple points across the hood (divided into a grid) to ensure consistent protection.

     - Upper Leg and Pelvis Tests:

       - An upper leg impactor simulates impact on the hood’s leading edge, measuring forces to the pelvis and femur.

       - Ensures the hood edge is not excessively rigid.

     - Lower Leg Tests:

       - A leg impactor tests the bumper and front grille, measuring tibia and knee ligament forces.

       - Ensures bumpers absorb energy to reduce fractures.

   - Scoring:

     - Up to 36 points for passive protection.

     - Points are awarded based on HIC, leg forces, and pelvis injury risk, with color-coded maps (green for safe, red for hazardous) showing performance across impact zones.

     - Example: A hood with low HIC scores (e.g., <650) and a deformable bumper scores higher.

 2. Active Safety Tests

Purpose: Evaluate AEB and other systems’ ability to detect and avoid VRUs.

 

Tests:

     - Pedestrian AEB:

       - Scenarios include adults/children crossing roads, walking along roads, or emerging from behind obstacles.

       - Speeds range from 10–60 km/h (6–37 mph).

       - Measures collision avoidance or speed reduction before impact.

     - Cyclist AEB:

       - Tests cyclists crossing or riding alongside the vehicle, including turning scenarios.

       - Speeds up to 60 km/h, with emphasis on detection accuracy.

     - Nighttime AEB:

       - Tests pedestrian and cyclist detection in low-light conditions using headlights and sensors.

     - Dooring Prevention:

       - Assesses systems that warn drivers of cyclists when opening doors.

   - Scoring:

     - Up to 18 points for AEB performance.

     - Points for full avoidance, significant speed reduction, or effective warnings.

     - Example: A vehicle that stops completely for a crossing pedestrian at 40 km/h scores higher.

 3. Total VRU Score

   - Maximum Score: 100 points (e.g., 36 for passive protection, 18 for AEB pedestrian, 18 for AEB cyclist, with additional points for specific scenarios).

   - Weighting: Contributes 20% to the overall Euro NCAP rating.

   - Impact on Rating: A VRU score of ~70% or higher is typically required for a 5-star rating, ensuring balanced performance across all categories.

Comparison with US NCAP

The US NCAP (NHTSA’s 5-Star Safety Rating Program) has historically focused on crashworthiness (frontal, side, rollover) and occupant protection, with limited emphasis on VRU protection. However, recent developments show convergence with Euro NCAP’s approach:

Euro NCAP VRU Protection

- Dedicated Category: VRU Protection is a distinct category (20% of rating), introduced in 2009 and expanded with AEB testing in 2016.

 Tests:

  - Passive: Head, upper leg, and lower leg impact tests across multiple vehicle zones.

  - Active: AEB for pedestrians and cyclists, including nighttime and dooring scenarios.

- Standards: Exceeds ECE Regulation No. 127 (mandatory since 2009), which requires pedestrian-friendly hoods and bumpers but does not include AEB testing.

- Scoring: Detailed, with separate points for passive (36) and active (18) protection, emphasizing both design and technology.

- Example: A vehicle with a pop-up hood and robust pedestrian AEB scores ~80%+, contributing to a 5-star rating.

US NCAP VRU Protection

- Limited Scope: Historically, US NCAP did not test VRU protection, focusing on occupant crashworthiness (FMVSS No. 208, 214).

- Proposed Changes (2022):

  - NHTSA proposed adding pedestrian AEB testing to US NCAP, with scenarios like pedestrian crossing (day/night) and turning collisions.

  - Tests would use pedestrian dummies at speeds up to 40 mph (64 km/h), measuring AEB effectiveness.

  - No passive protection tests (e.g., hood impacts) are currently proposed, unlike Euro NCAP.

- Standards: Aligns with proposed FMVSS No. 127 (pedestrian AEB, not yet mandatory) but lags behind EU’s ECE R127.

- Scoring: If implemented, pedestrian AEB would contribute to an updated rating system, but details are pending (as of 2025).

- Example: A vehicle with effective pedestrian AEB would improve its rating under proposed changes, but no passive protection score exists.

Comparison:

- Scope: Euro NCAP’s VRU testing is far more comprehensive, covering both passive (hood/bumper design) and active (AEB) measures, while US NCAP’s VRU focus is emerging and limited to AEB.

- Test Rigor: Euro NCAP tests a wider range of scenarios (e.g., cyclist dooring, nighttime AEB) and passive impact zones, while US NCAP’s proposed tests are narrower.

- Regulatory Context: Euro NCAP exceeds ECE R127, while US NCAP’s VRU efforts are not yet mandatory, lagging behind EU regulations.

- Impact on Ratings: Euro NCAP’s VRU category (20%) directly affects star ratings, while US NCAP’s VRU tests (if adopted) will be a smaller component.

Mandatory Standards for VRU Protection

European Union: ECE Regulation No. 127:

  - Since: 2009 (updated 2019 under EU General Safety Regulation 2019/2144).

  - Requirements:

    - Hoods and bumpers must minimize head and leg injuries (HIC <1,000 for most zones).

    - Tests head impacts (40 km/h) and leg impacts, similar to Euro NCAP but less extensive.

    - AEB for pedestrians/cyclists became mandatory for new vehicles in 2022.

  - Scope: Applies to passenger cars and light commercial vehicles.

United States:

  - No Mandatory Standard: No equivalent to ECE R127 for passive protection exists in FMVSS.

  - Proposed FMVSS No. 127: NHTSA proposed mandating pedestrian AEB by 2029, with tests similar to Euro NCAP’s AEB scenarios.

Global: UNECE’s Global Technical Regulation (GTR) No. 9 harmonizes pedestrian protection standards, adopted by the EU, Japan, and others, but not the U.S.

Euro NCAP’s VRU tests significantly exceed ECE R127 by including cyclist AEB, nighttime scenarios, and more extensive passive impact zones, while US NCAP’s proposed VRU tests are still in development and less comprehensive.

Integration with TPMS

Tire Pressure Monitoring Systems (TPMS), mandated by ECE Regulation No. 64 in the EU and FMVSS No. 138 in the U.S., indirectly support VRU protection by ensuring vehicle stability and optimal braking performance:

Euro NCAP:

  - Role: TPMS ensures proper tire pressure (detecting 25% loss within 10–60 minutes), enhancing AEB performance in VRU tests (e.g., stopping for a crossing pedestrian).

  - Impact: Underinflated tires reduce braking efficiency, increasing collision risk or impact speed, which lowers AEB scores in the VRU category (18/54 points).

  - Synergy: TPMS supports Safety Assist (20% of rating), which includes AEB, indirectly boosting VRU protection by preventing collisions.

US NCAP:

  - Role: TPMS ensures tire performance, critical for proposed pedestrian AEB tests, where braking efficiency is key.

  - Impact: Proper tire pressure reduces stopping distances, supporting AEB effectiveness in future VRU tests.

  - Synergy: TPMS enhances rollover and crash performance, indirectly supporting VRU safety by maintaining vehicle control.

- Comparison:

  - Euro NCAP explicitly ties TPMS to Safety Assist and VRU scores through AEB performance, while US NCAP’s TPMS role is less direct, supporting proposed AEB tests.

  - Both programs rely on TPMS to ensure stability, but Euro NCAP’s broader active safety focus amplifies its VRU relevance.

Testing and Evaluation

Euro NCAP:

  - Dummies and Impactors: Uses adult/child head impactors, upper leg/pelvis impactors, and lower leg impactors for passive tests; pedestrian/cyclist dummies for AEB tests.

  - Scenarios: Tests head impacts across a hood grid, leg impacts on bumpers, and AEB in crossing, parallel, and nighttime scenarios.

  - Criteria: HIC (<1,000), leg forces (<6 kN for tibia), pelvis forces (<6 kN), and AEB speed reduction or avoidance.

  - Real-World Relevance: Reflects urban accidents (e.g., 40% of EU pedestrian deaths occur at crosswalks).

US NCAP:

  - Dummies: Proposed pedestrian AEB tests use articulated pedestrian dummies.

  - Scenarios: Proposed tests include crossing pedestrians (day/night) and turning collisions at speeds up to 40 mph.

  - Criteria: Focus on AEB effectiveness (e.g., stopping or speed reduction), no passive protection tests.

  - Real-World Relevance: Addresses growing U.S. pedestrian fatalities (6,700 in 2020), but less comprehensive than Euro NCAP.

Impact of VRU Protection

1. Reduced Fatalities and Injuries:

   - Euro NCAP’s VRU focus has driven adoption of pedestrian AEB and softer vehicle designs, reducing pedestrian deaths by ~20% in Europe since 2009.

   - US NCAP’s proposed AEB tests aim to address rising pedestrian fatalities (up 53% from 2009–2020).

2. Vehicle Design Improvements:

   - Manufacturers adopt pop-up hoods, deformable bumpers, and advanced AEB systems to achieve high Euro NCAP VRU scores.

   - US NCAP’s future VRU tests will encourage AEB adoption but lack passive protection incentives.

3. Consumer Awareness:

   - Euro NCAP’s VRU scores (published on www.euroncap.com) guide buyers toward pedestrian-safe vehicles.

   - US NCAP’s Monroney sticker ratings will include AEB performance if proposed changes are adopted.

4. Global Influence:

   - Euro NCAP’s VRU protocols are adopted by Australasian NCAP, Latin NCAP, and Bharat NCAP, influencing global standards like GTR No. 9.

   - US NCAP’s VRU focus is emerging but less influential globally.

Challenges and Criticisms

Euro NCAP:

  - Cost: VRU features (e.g., AEB, pop-up hoods) increase vehicle prices, challenging budget models.

  - Complexity: Testing multiple impact zones and AEB scenarios requires sophisticated facilities.

  - Urban Bias: Tests focus on urban scenarios, potentially less relevant in rural areas.

US NCAP:

  - Delayed Adoption: Lack of VRU testing until recently lags behind global standards.

  - Limited Scope: Proposed AEB tests exclude passive protection, unlike Euro NCAP.

  - Regulatory Lag: No mandatory VRU standard (unlike EU’s ECE R127) limits impact.

Future of VRU Protection

Euro NCAP:

  - Expanding nighttime AEB and cyclist-specific tests (e.g., e-scooter detection).

  - Integrating VRU protection with autonomous vehicle protocols, focusing on sensor reliability.

  - Stricter passive protection criteria (e.g., lower HIC thresholds).

US NCAP:

  - Implementing pedestrian AEB tests by 2026–2029, aligning with proposed FMVSS No. 127.

  - Potential future inclusion of passive protection tests as pedestrian fatalities rise.

- Global Trends:

  - Harmonization via UNECE GTR No. 9 to standardize VRU protection.

  - Increased focus on micromobility (e.g., e-scooters, skateboards) in urban areas.

Conclusion

Vulnerable Road User (VRU) Protection is a critical safety focus, addressing the high risk of injury to pedestrians and cyclists in vehicle collisions. Euro NCAP leads with a comprehensive VRU category (20% of its 5-star rating), testing both passive (hood/bumper design) and active (AEB) measures, exceeding ECE R127 standards. US NCAP is catching up with proposed pedestrian AEB tests but lacks passive protection testing, making it less robust. 

TPMS supports both programs by ensuring tire performance, enhancing AEB and vehicle stability critical for VRU safety. Euro NCAP’s VRU focus has greater global influence, driving innovations like pop-up hoods and cyclist AEB, while US NCAP’s emerging efforts aim to address rising pedestrian fatalities. For detailed vehicle VRU ratings, check www.euroncap.com or www.nhtsa.gov/ratings.