Previous Employer Inquiries: How to Get 391.23 Right

The Violation That Hides in Plain Sight

Ask a fleet manager to name the documents in a driver qualification file and they will get most of the list: the application, the CDL copy, the medical certificate, the MVR. The previous employer inquiry usually comes last, if it comes up at all. Yet it is consistently among the most-cited driver qualification violations in FMCSA investigations. In 2024 alone, investigators cited carriers under 49 CFR 391.23 more than 800 times.

The reason is structural. Every other document in the file depends only on you and your driver. The previous employer inquiry depends on someone else, a former employer with no incentive to answer quickly or at all. Carriers send a request, hear nothing, and move on. Months later an auditor opens the file, finds no responses and no record of follow-up, and writes the violation.

This guide walks through what 391.23 actually requires, who you have to contact, what to ask for, and the part that saves you when a previous employer ghosts you: good faith effort documentation.

What 391.23 Actually Requires

When you hire a driver, 49 CFR 391.23 requires two separate inquiries, both on the same deadline:

1. The motor vehicle record inquiry. Within 30 days of the date employment begins, you must request an MVR from every state where the driver held a license or permit during the preceding 3 years. Our guide to FMCSA MVR requirements covers this half in depth.

2. The safety performance history investigation. You must investigate the driver's safety performance history with every DOT-regulated employer that employed the driver during the preceding 3 years. The results of that investigation, or documentation of your good faith efforts to obtain them, must be in the driver's investigation history file within the same 30 days.

The driver can operate while the investigation is pending. What cannot happen is the deadline passing with nothing in the file. The 30-day clock starts on the driver's first day of employment, not the day you get around to sending letters, and it does not pause while you wait for a response.

Who Counts as a Previous Employer

The lookback is 3 years, and the net is wider than most carriers assume. You must contact every DOT-regulated employer from that period, which means any employer whose drivers were subject to Department of Transportation safety regulations. That includes other motor carriers, but also employers regulated by other DOT agencies such as the FRA, FTA, FAA, or PHMSA.

Where do you get the list? From the employment application. Under 391.21, a driver applying for a CMV position must account for the past 10 years of employment, with commercial driving experience identified. The 3-year window of DOT-regulated employers on that application is your contact list. This is one of the reasons auditors read applications as timelines: an unexplained gap in the dates can also be a previous employer you never contacted.

A non-DOT employer in the window (a warehouse job, a retail stint) does not require a safety performance inquiry. The rule targets employers who would hold safety data: accident history and drug and alcohol testing records.

What You Must Ask For

The investigation covers three categories of information:

Category	What it includes
Employment verification	General driver identification and confirmation that the driver worked there, and when
Accident history	Any accidents involving the driver in the 3 years before the application, as defined by 390.5, plus any smaller incidents the employer keeps under its own policies
Drug and alcohol history	Whether the driver violated DOT testing regulations, and whether a driver who did complete the required return-to-duty process

The drug and alcohol portion requires the driver's written consent, and that authorization belongs in the file alongside the responses. For most hires, though, this third category is no longer collected by contacting employers directly, which brings us to the biggest change in how 391.23 works.

The Clearinghouse Carve-Out

Since January 6, 2023, the FMCSA Drug and Alcohol Clearinghouse has replaced the manual drug and alcohol inquiry for previous employers regulated by FMCSA. Under 391.23(e)(4), employers required to run pre-employment Clearinghouse queries satisfy the drug and alcohol portion of the investigation with that query. Three years of violation data had accumulated in the Clearinghouse by that date, so the database now answers the question the faxes used to ask.

Two boundaries keep this carve-out from being a blanket exemption:

• It only covers FMCSA-regulated previous employers. If the driver worked for an employer regulated by another DOT agency (FRA, FTA, FAA, PHMSA), you must still contact that employer directly for drug and alcohol history.
• It only covers the drug and alcohol portion. The safety performance history inquiries under 391.23(c) and (d), covering employment verification and accident history, are still required for every DOT-regulated previous employer. The Clearinghouse tells you nothing about accidents.

If your onboarding checklist dropped previous employer inquiries entirely when the Clearinghouse arrived, it went one step too far. See our Clearinghouse guide for the query mechanics and deadlines.

Good Faith Efforts: What Auditors Accept

Previous employers are required to respond, but plenty do not. The regulation anticipates this. If you cannot obtain the information, you must document a good faith effort to get it, and that documentation stands in for the missing response.

What survives an audit is specific and dated:

• The date of each attempt. Day one, a follow-up in week two, another in week three.
• The method of each attempt. Letter, email, fax, phone call, or a third-party verification service. Vary them; three unanswered emails to a dead inbox looks like a formality, not an effort.
• Who you tried to reach. The company name and address, and the contact if you had one.
• The result. No response, a refusal, a disconnected number. Write it down either way.

A single letter with no follow-up is where carriers get cited even though they technically tried. The pattern auditors want to see is a real attempt to obtain the data before the 30-day window closed, not a paper gesture. If the employer never answers, your log of attempts goes in the file and you are compliant. Non-response by a previous employer is not a violation on your part. An empty file is.

Our breakdown of the most common DOT audit violations has a simple cadence that works: send inquiries on day 1, follow up at day 14 and day 21, and log everything.

When You Are the Previous Employer

391.23 runs in both directions. When another carrier sends you an inquiry about a driver who used to work for you, paragraph (g) puts you on a clock: you must respond within 30 days of receiving the request, providing the accident and employment information the rule specifies. If you have no safety performance history on the driver, you must still respond and say so. Silence is not an option, and you must keep a record of each request and your response for 1 year under 391.23(g)(4).

Small fleets miss this side of the rule constantly, because nothing about day-to-day operations surfaces an inbound verification request as a regulated deadline. Assign the responsibility to a named person, the same way you assign outbound inquiries.

The Driver's Rights

The safety performance history is about the driver, and the driver has enforceable rights in the process:

• Review. A driver can submit a written request to see the information you received, up to 30 days after being hired. You must provide it within 5 business days.
• Correction. If the driver disputes an entry, the previous employer that supplied it must either correct it and forward the corrected version to you, or notify the driver that it stands, within 15 days of the correction request.
• Rebuttal. A driver who cannot get an entry changed can submit a rebuttal, and the previous employer must forward that rebuttal to you within 5 business days.

You cannot refuse to hire a driver for exercising these rights. Practically, this means your process needs to tell drivers the information was collected and route a written request to whoever holds the file, inside a week.

Where the Records Go and How Long to Keep Them

Previous employer inquiry responses do not live in the general DQ file. Under 49 CFR 391.53, they belong in a separate driver investigation history file with restricted access: only people involved in the hiring decision (or who control access to the data) may see it, your insurer may see everything except the drug and alcohol data, and the data may be used only for the hiring decision.

Retention is the duration of employment plus 3 years after the driver leaves. For the full retention picture across the DQ file, drug and alcohol records, and inquiry responses, see our DQ file retention guide.

Record	Where it lives	How long to keep it
Inquiry responses and good faith effort logs	Driver investigation history file	Employment + 3 years
Driver's written consent for drug/alcohol history	Driver investigation history file	Employment + 3 years
Your responses to other carriers' inquiries	Your own records	1 year from the response

A Deadline That Only Runs Once

Most DQ file requirements are recurring. Medical certificates renew, MVRs get pulled annually, Clearinghouse queries repeat every 12 months. The previous employer inquiry is different: it has one 30-day window at the start of employment, and once that window closes, it cannot be reopened. An inquiry sent in month six is evidence of the violation, not a cure for it.

That makes it exactly the kind of requirement that falls through the cracks of a busy onboarding week, and exactly the kind a system should own. Core Compliance tracks the previous employer inquiry as one of the 14 document types in every driver's file, flags any driver missing it, and keeps the record attached to the driver so the response, or your good faith effort log, is one click away when an auditor asks.

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