INFORMATION REQUIRED IN PROXY STATEMENT
SCHEDULE 14A INFORMATION
Proxy Statement Pursuant to Section 14(a) of the
Securities Exchange Act of 1934
(Amendment No. )

Step 1: Go to www.envisionreports.com/PTRA Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. www.envisionreports.com/PTRA Online Go to www.envisionreports.com/PTRA or scan the QR code — login details are located in the shaded bar below. Stockholder Annual Meeting Notice 30MI0B + + Important Notice Regarding the Availability of Proxy Materials for the 2022 Annual Meeting of Stockholders of Proterra Inc to be Held Virtually on May 26, 2022. Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the 2022 Annual Meeting of Stockholders of Proterra Inc are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. Our proxy statement and 2021 Annual Report to Stockholders are available at: Obtaining a Copy of the Proxy Materials – If you want to receive a copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. Please make your request as instructed on the reverse side on or before May 16, 2022 to facilitate timely delivery. 2NOT Easy Online Access — View your proxy materials and vote. When you go online, you can also help the environment by consenting to receive electronic delivery of future materials. Step 4: Make your selections as instructed on each screen for your delivery preferences. Step 5: Vote your shares.

Here’s how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below. If you request an email copy, you will receive an email with a link to the current meeting materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials. — Internet – Go to www.envisionreports.com/PTRA. Click Cast Your Vote or Request Materials. — Phone – Call us free of charge at 1-866-641-4276. — Email – Send an email to investorvote@computershare.com with “Proxy Materials Proterra Inc” in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials. To facilitate timely delivery, all requests for a paper copy of proxy materials must be received by May 16, 2022. The 2022 Annual Meeting of Stockholders of Proterra Inc will be held on Thursday, May 26, 2022 at 8:00 a.m., Eastern Time, virtually via the Internet at www.meetnow.global/MZ4W7DZ. To access the virtual meeting, you must have the information that is printed in the shaded bar located on the reverse side of this form. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommends a vote FOR all the nominees listed in Proposal 1, Every 1 Year on Proposal 2, and FOR Proposal 3: The Board of Directors recommends that you vote FOR the following nominees. 1. Election of Directors: Mary Louise Krakauer Roger M. Nielsen Jeannine P. Sargent The Board of Directors recommends that you vote Every 1 Year on the following proposal. 2. To approve, on an advisory basis, the frequency of holding an advisory vote on our named executive officer compensation. The Board of Directors recommends that you vote FOR the following proposal. 3. To ratify the appointment of KPMG LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2022. NOTE: Transact any other business properly brought before the annual meeting and any postponements or adjournments thereof. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must go online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please have this notice with you. Stockholder Annual Meeting Notice

¨	Preliminary Proxy Statement

¨	Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨	Definitive Proxy Statement

x	Definitive Additional Materials

¨	Soliciting Material under §240.14a-12