Why is it important to check emissions at both high and low speeds?

Checking emissions at both high and low speeds is essential to assess vehicle performance under different operating conditions. Vehicles function differently depending on their speed, which impacts their emissions output. An evaluation at high speeds mimics conditions like highway driving, where engines work harder and typically generate different emission levels compared to lower speeds, which represent city driving or idling.

By testing emissions across this spectrum, inspectors can identify inconsistencies or issues that might only become apparent under specific conditions. This comprehensive approach allows for a more thorough assessment of the vehicle's emission control system and overall compliance with environmental standards. It provides valuable data that can inform necessary repairs or adjustments to ensure the vehicle operates efficiently and within regulatory limits.