Contribution of brake particle emissions to ambient PM2.5 is increasing. Previous studies focused on determination of brake emission rate from lab testing and so it lacks brake activity of real world conditions. The study aimed to establish a test method to determine brake activity of a heavy-duty vehicle. Brake parameters and vehicle parameters were measured during two chassis cycles and two on-road test tests. Brake activity was quantified with brake pressure signal as the first indicator and vehicle speed as the second indicator. Temperature increase was related to the kinetic loss of the vehicle and cooling and heating of brake pad was repeated during on road test. Resulting brake activity was presented in the form of histogram. Future test should use shorter copper cap for thermocouple to better sense friction surface temperature. It is recommended to measure both activity and emissions during on-road test so that a better relationship can be established between brake activity and brake particle emissions.
