Investigations
Thomas Built CNG Tank Abrasion
NHTSA Preliminary Evaluation PE11029 - closed, opened 2011-09-02.
NHTSA investigation PE11029 is a Preliminary Evaluation opened on 2011-09-02 and currently closed. The subject is tracked inside the Office of Defects Investigation queue. Latest activity on this investigation was logged on 2012-02-17 - NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
A Preliminary Evaluation like PE11029 is the entry point of the federal defect-investigation process. NHTSA engineers scan complaint databases, field reports, and manufacturer data to decide whether an Engineering Analysis is warranted, whether a voluntary recall is already sufficient, or whether the pattern does not rise to a defect finding.
Investigators summarized the matter as follows: "On August 29, 2011 ODI received a Vehicle Owner's Questionnaire (VOQ) from a Los Angeles school district indicating a 2003 Thomas Built Saf-T-Liner HDX compressed natural gas (CNG) school bus in their fleet had insuffici..." Investigations are the early-warning layer of the federal auto-safety system, sitting upstream of formal recalls and defect orders. Whether this one closes without action or escalates into an Engineering Analysis, the full history stays in the ODI archive so researchers, litigators, and buyers can pull the paper trail at any time.
Investigation Summary
On August 29, 2011 ODI received a Vehicle Owner's Questionnaire (VOQ) from a Los Angeles school district indicating a 2003 Thomas Built Saf-T-Liner HDX compressed natural gas (CNG) school bus in their fleet had insufficient clearance between the CNG tank and mounting bracket resulting in damage to the outer tank wrapping. The Mathematical Analysis Division of NHTSA calculated that a sample size of thirty (30) buses would give a high confidence (90%) estimation of whether similar buses were experiencing tank abrasion. In the course of this investigation nearly 70 buses (over 300 tanks) were inspected; no tank other than the subject of the VOQ was found to have insufficient clearance. Busses manufactured before and after the subject vehicle were inspected. As a result of this investigation, Daimler Trucks North America (DTNA) developed an improved inspection procedure that addresses the concerns identified in the Los Angeles complaint. In early February 2012 DTNA will mail an owner letter along with the new inspection procedure. See the investigative file for copies of DTNA's bulletin and owner letter. This preliminary evaluation is closed. The closing of this investigation does not constitute a finding by NHTSA that no safety-related defect exists. The agency reserves the right to take further action if warranted by circumstances. The ODI report cited above can be reviewed at www-odi.nhtsa.dot.gov/owners/SearchNHTSAID under the following identification (ODI) number: 10423400
About This Investigation Type
A Preliminary Evaluation (PE) is the first phase of NHTSA's investigation process. It is opened when the agency identifies a potential safety defect pattern, usually triggered by consumer complaints, manufacturer reports, or field monitoring. During a PE, NHTSA gathers information to determine whether a formal engineering analysis is warranted.
Data from NHTSA Office of Defects Investigation. Cross-references: NHTSA recall campaign API and NHTSA FARS where fatality records overlap. PlainCars does not rate or recommend vehicles. about how PlainCars sources NHTSA data.
Read our methodology - how this data is sourced, computed, and verified.