Measuring What Matters: Real-World Emissions and Noise from L-Category Vehicles - Insights from the Horizon Europe “LENS” Project

LENS generated one of the most comprehensive real-world datasets to date for L-category exhaust and noise emissions, helping inform future measurement approaches and regulatory discussions.

Urban mobility is evolving rapidly, but one challenge remains constant: improving air quality and reducing noise in cities requires reliable data from real driving conditions. From 2022 to 2025, the Horizon Europe project LENS brought together 15 partners from industry and academia, including HORIBA, to better understand real-world exhaust and noise emissions from L-category vehicles - mopeds, motorcycles, trikes, and quadricycles.

While L-category vehicles represent a smaller share of total road traffic than passenger cars, their diversity of technologies and design features, space and power constraints, wide range of vehicle ages, and highly dynamic operating conditions can lead to a meaningful contribution to urban air pollution and noise, especially in dense environments.

LENS first aimed to build a robust database of real‑world emissions. This dataset was then used to assess mitigation scenarios, quantify their impacts, and support future regulatory approaches.

Emissions and noise are typically assessed through standardized test procedures. However, real driving involves frequent accelerations, full throttle operation, varying loads, different road gradients, and diverse rider behavior - conditions that are difficult to fully replicate in laboratory settings, particularly for lightweight two-wheelers where safely reproducing high-load transients can be challenging.

LENS highlights a key message for the mobility ecosystem: real-world measurement is essential to understand actual environmental impact, identify where gaps may exist relative to type-approval results, and help develop measurement approaches and test procedures that perform well on the road - not just on a test cycle.

To build a comprehensive picture of L-category vehicle performance, LENS combined multiple complementary approaches:

• Laboratory and test-track testing, enabling controlled comparisons across vehicles and technologies
• Real-driving measurements, capturing emissions and noise under everyday operating conditions
• Roadside remote sensing campaigns, assessing many vehicles in real traffic environments
• Assessment of  mitigation measures, including their impacts and cost-benefit implications.

Across the project, more than 150 vehicles were analyzed through laboratory, track, and real-driving activities. In addition, around 2,300 vehicles were assessed via roadside remote sensing campaigns in Leuven, Paris, and Barcelona.

The resulting dataset provides a strong basis for evaluating mitigation options, simulating their potential impact, and developing evidence-based recommendations for current and future  L-category vehicle fleets.

The project observations suggest that real-world emissions can exceed type-approval values under certain operating conditions, with notable effects observed for particle number (PN) and some unregulated pollutants such as ammonia.

On the noise side, LENS measurements indicate that everyday riding can produce louder events than those captured by current test procedures, highlighting the importance of measurement approaches that reflect real usage.

LENS also identified tampering (vehicle modifications, often exhaust-related) as a relevant issue in the real-world fleet, highlighting the importance of effective in-use compliance measures.

Based on the evidence generated, LENS formulated recommendations that may inform future EU approaches, including:

• Introducing Real Driving Emissions (RDE) testing for L-category vehicles to better reflect dynamic real-world conditions
• Updating noise test procedures to capture representative real-use noise events
• Expanding and refining PN measurement procedures and regulations, including the growing interest in ultrafine particles
• Strengthening Periodic Technical Inspection (PTI) and anti-tampering measures to help ensure in-use compliance

These directions reflect a broader trend: environmental performance increasingly depends not only on design intent, but also on in-use behavior, durability, and real-world compliance.

Together, these recommendations aim to improve representativeness, comparability, and in-use compliance—so that measured performance better reflects real-world urban driving.

As part of the consortium, HORIBA Europe played a central role in developing and evaluating compact on-board measurement technologies tailored to the practical constraints of lightweight two-wheelers.

Adapting and enhancing HORIBA’s Sensor-based Emissions Measurement System (SEMS) platform and the Automotive Emission Analyzer MEXA-584L (miniPEMS) for real-world use on small motorcycles, with a focus on robustness, mounting feasibility, and OBD-based data integration

Supporting the integration and evaluation of an experimental on-road PN sensor concept targeting ultrafine particles in the nanometer range, down to 2.5 nm.

Participating in consortium-wide round-robin comparisons across PEMS, miniPEMS, and SEMS, supporting consistency and confidence in measurement approaches

Providing systems for on-road measurement campaigns and contributing to technical discussions related to potential future RDE procedures for L-category vehicles

Projects like LENS demonstrate how measurement innovation and collaborative research can accelerate progress toward cleaner, quieter mobility. As regulatory frameworks evolve and interest grows in real-world performance -including ultrafine particle measurement- HORIBA will continue supporting stakeholders with reliable measurement technologies and expertise.

LENS (L-vehicles Emissions and Noise mitigation Solutions)

Motorcycle Test & Measurement Solutions

PEMS Testing | Portable Emission Measurement System

MEXA-584L Portable Engine Exhaust Emission Analyzer