X0306 4 2021-06-14 0 0001820630 ArcLight Clean Transition Corp. PTRA 0001866249 Ensign Joshua P C/O PROTERRA INC 1815 ROLLINS ROAD BURLINGAME CA 94010 0 1 0 0 Chief Operating Officer Common Stock 2021-06-14 4 A 0 21796 A 21796 D Stock Option (Right to Buy) 2.01 2021-06-14 4 A 0 177642 A 2026-11-16 Common Stock 177642 177642 D Stock Option (Right to Buy) 2.01 2021-06-14 4 A 0 438520 A 2026-11-16 Common Stock 438520 438520 D Stock Option (Right to Buy) 2.01 2021-06-14 4 A 0 133875 A 2026-12-15 Common Stock 133875 133875 D Stock Option (Right to Buy) 4.26 2021-06-14 4 A 0 446249 A 2028-05-16 Common Stock 446249 446249 D Stock Option (Right to Buy) 5.98 2021-06-14 4 A 0 337365 A 2029-08-20 Common Stock 337365 337365 D Stock Option (Right to Buy) 4.62 2021-06-14 4 A 0 8924 A 2030-08-19 Common Stock 8924 8924 D Stock Option (Right to Buy) 4.78 2021-06-14 4 A 0 22312 A 2030-12-20 Common Stock 22312 22312 D Stock Option (Right to Buy) 4.78 2021-06-14 4 A 0 22312 A 2030-12-20 Common Stock 22312 22312 D Pursuant to the business combination of ArcLight Clean Transition Corp. and Proterra Inc ("Old Proterra"), each share of Old Proterra outstanding common stock was automatically converted into the right to shares of the Issuer's Common Stock based on a 1 to 0.8925 conversion ratio ("Conversion Ratio"). In addition, each outstanding Old Proterra equity award was automatically converted into a corresponding equity award of the Issuer based on the Conversion Ratio and with the same terms and vesting conditions as the Old Proterra equity awards. This option is fully vested. 6.25% of the total shares underlying the option vest quarterly installments until fully vested, subject to the Reporting Person's continued service to the Issuer on each vesting date. /s/ Joshua Damm, Attorney-in-Fact 2021-06-16