Zoox preliminary evaluation PE24015
Rear-end Collisions Involving Zoox Vehicles. NHTSA’s Office of Defects Investigation opened this preliminary evaluation about the software on 2 model years (2023–2024). Opened May 10, 2024, closed Mar 31, 2025 after 11 months. It led to safety recall 25E019000. became a recall
What NHTSA says
Source: Office of Defects Investigation, as filedOn May 10, 2024, the Office of Defects Investigation (ODI) opened a Preliminary Evaluation (PE24015) to assess reports of sudden unexpected braking in Zoox vehicles, leading to rear-end collisions, as well as to evaluate the performance of the Zoox Automated Driving System in crosswalks around vulnerable road users and in other similar rear-end collision scenarios. These unexpected braking events can increase the risk of a collision. To assess these risks, ODI collected information from Zoox as part of this investigation. In response to ODI’s Request for Information, Zoox provided information describing hard braking events commanded by the ADS. These hard braking events were identified by certain thresholds, including rate of deceleration. ODI analyzed the hard braking events commanded by the Zoox ADS and determined that Zoox ADS-equipped vehicles contributed to 4 collisions. Each of these collisions involved a vulnerable road user, with three of the incidents resulting in injury. Three of the collisions were reported under Standing General Order 2021-01 (SGO), while the other collision was not reportable under the SGO. On March 13, 2025, Zoox �led a safety recall (NHTSA Recall No. 25E019) stating that in specific circumstances “the Zoox ADS software may have reacted over-cautiously and braked unnecessarily hard� and that “the Zoox ADS software may have incorrectly anticipated a collision and braked unnecessarily hard.� These behaviors could lead to increased risk of a rear-end collision caused by unnecessary hard braking. The Zoox recall report indicated that Zoox's ADS has been remedied through a software update that addresses the described defects. As of November 7, 2024, the updated software was released to all impacted Zoox vehicles. In view of the recall action taken by Zoox and ODI’s analysis of the available data, including data presented by Zoox demonstrating a resolution of these hard braking incidents after the software update, ODI is closing this Preliminary Evaluation. NHTSA reserves the right to take additional action if warranted by new circumstances. To review the SGO reports cited above, go to NHTSA.gov/laws-regulations/standing-general-order-crash-reporting. The SGO report ID numbers are provided below: 30610-7578    30610-7589    30610-4810
A Preliminary Evaluation is the first formal stage: NHTSA has decided the complaints and other information it screened are worth a closer look, and asks the manufacturer for its own data on the condition. The summary is the agency’s own text from its investigation file, unedited; the opening and closing resumes with the full reasoning are on NHTSA’s site under this number.
What this means for an owner
Source: and what happens nextAn investigation is not a finding that a defect exists, and it puts no duty on anyone. NHTSA opens a Preliminary Evaluation when complaints and other reports suggest a condition worth asking the manufacturer about; it upgrades to an Engineering Analysis when the answers warrant testing; it closes either when it recommends a recall, when the manufacturer recalls on its own, or when no defect trend is found. The agency’s own goals are about four months for a petition, eight for a Preliminary Evaluation or a Recall Query and eighteen for an Engineering Analysis; many run longer.
This one became a recall. The campaign page carries the manufacturer’s filed defect, risk and remedy, the build window and every model year covered; whether one specific vehicle is included is settled by VIN at nhtsa.gov/recalls.
Model years it names
Source: as NHTSA filed themAlso named: 2023 Zoox Zoox Robotaxi; 2024 Zoox Zoox Robotaxi.
A vehicle page’s investigation list carries the same action; a name here is the scope NHTSA opened, not a list of affected VINs.
Common questions
Source: NHTSA Office of Defects InvestigationIs PE24015 a recall?
No — it is the investigation that led to one. Recall 25E019000 is the campaign; its page carries the remedy.
Is PE24015 still open?
No. It closed on Mar 31, 2025 and led to recall 25E019000.
Which vehicles does PE24015 cover?
NHTSA opened it on 2 model years: 2023 Zoox Zoox Robotaxi, 2024 Zoox Zoox Robotaxi. That is the scope of the inquiry, not a list of affected vehicles; a recall, if one follows, defines its own population by VIN.