Research methods
Automotive market research: read the supplier rulebook before you size the market
Automotive market research for suppliers starts with the carmaker's published supplier rules, then sizes demand with public production and sales data, then interviews buyers.
Automotive market research for a supplier or startup has to answer three questions: who signs off on buying from you, what you must prove before they can, and how many vehicles your product rides on. It is tempting to start with the third question because it makes the nicest slide. Start with the second. Carmakers publish their supplier rules, and those rules decide your sales cycle more than any forecast does.
The work splits cleanly. The buyer's own published requirements tell you the rules. Public government data tells you the volumes. Interviews with procurement, engineering and dealer staff tell you how a decision actually moves through a company. For the general method behind that split, see B2B market research.
1. Read the carmaker's rulebook first, because it is public
The baseline quality standard for automotive suppliers is IATF 16949. The International Automotive Task Force describes it as the automotive quality management system standard, says it replaced ISO/TS 16949:2009, and keeps it aligned with ISO 9001. On top of it, each carmaker adds its own rules, called customer-specific requirements. The IATF's customer-specific requirements page links documents from ten vehicle makers, including Ford, General Motors, Stellantis, Volkswagen and BMW.
These documents read like a contract because they are close to one. A few lines that change what a newcomer should expect:
- Ford's requirements say production and service part suppliers must be third-party registered to IATF 16949 through an IATF-recognized certification body to achieve Ford's Q1 supplier status. Ford may waive that for some suppliers, at its option.
- The same document says tooling and equipment suppliers to Ford are not eligible for IATF 16949 certification, and that ISO 9001 registration is acceptable for them.
- GM's requirements require suppliers to hold a Sourceability Level of 3, 4 or 5, and describe a special status called New Business Hold that GM can place a supplier on.
So the first research task is a reading task. Work out whether you would ship a part that goes into the vehicle, sell equipment to a plant, or sell software and services. Then read the relevant sections of the requirements for the two carmakers you care about most. (Budget an afternoon and a lot of coffee. The Ford document alone runs to 44 pages.)
Short version: if you make a production part and have no IATF 16949 certificate, that gap, not demand, is your first constraint.
2. Find out whether your sale forces your customer to redo an approval
Production Part Approval Process (PPAP) is the industry's way of proving a supplier can make a part to spec at volume. AIAG, the industry group that publishes the manual, calls it the industry standard for production part approval and says it exists so suppliers show they can produce parts with consistent quality in real production runs.
The part startups miss is what triggers a new submission. Ford's PPAP requirements list, among other cases: all new tooled parts, design changes including running changes on vehicles already in production, any change in the manufacturing process after approval, and any added or modified production tooling or equipment.
Read that last line from the point of view of a tier-1 supplier (a company that ships directly to the carmaker). If your new machine or process goes into their line, they may owe their customer a fresh submission. That is paperwork and risk for your champion, on top of your price. Ask about it in the first conversation.
The same document names the people involved. At Ford, the authorized customer representative for a supplier site's submissions is a Supplier Technical Assistance site engineer, and the Ford buyer is the contact when Ford directs which sub-tier supplier a tier 1 must use. That gives you a starting list of roles to interview before you ever see an org chart.
3. Size the market with production and registrations, then check against sales
Public data answers the counting questions well, and it is free. Pick the measure that matches how your product gets paid for.
| If you are paid per | Start with | What it shows |
|---|---|---|
| Vehicle built in the US | Federal Reserve G.17, table 3 | Monthly motor vehicle assemblies, in millions of units at a seasonally adjusted annual rate |
| New vehicle sold | BEA light vehicle sales, via FRED | Monthly sales of cars and light trucks from BEA's Supplemental Estimates, Motor Vehicles |
| Vehicle on the road (aftermarket, service) | FHWA table MV-1 | Registered vehicles by state and type |
| Supplier plant in a region | Census County Business Patterns | Establishments, employment and payroll by industry, down to the county |
A few current numbers to anchor on. US assemblies ran at 10.21 million a year in September 2026, of which 8.81 million were light trucks and 1.07 million were cars, per the Fed (these monthly rates get revised). Light vehicle sales ran at 15.98 million a year in the same month, per BEA. By our calculation, light vehicle sales exceeded the 9.89 million light vehicles assembled by about 6.1 million a year, a gap filled mostly by imported vehicles, net of exports, plus changes in inventory. If you sell into US plants, the 10 million is your universe. If you sell to drivers, the 16 million is. FHWA counted 297.5 million registered motor vehicles in 2024, including 97.4 million automobiles and 189.8 million trucks.
For supplier geography, County Business Patterns reports establishments by industry. Motor vehicle parts manufacturing is NAICS code 3363, as listed in the Fed's industry table. Counting parts plants by county tells you where to put a sales engineer long before any vendor report does.
4. Interview the people who touch a sourcing decision
Public data will not tell you who can say yes. For that, talk to people who have done the job. Three groups matter most, and they want different things from you. Interviewing B2B buying roles covers the general technique; here is what to ask in automotive.
Purchasing. A buyer or commodity manager at a carmaker or tier 1. Ask how a new supplier got onto the approved list the last time it happened, how long it took, and who had to sign. Ask what made them say no to the last newcomer.
Engineering and supplier quality. A product or manufacturing engineer, plus a supplier quality engineer. Ask what a change like yours would trigger in their approval process, what testing they would demand, and when in a vehicle program they would need to see it. Ask them which line of the customer-specific requirements would worry them first.
Dealer staff. Only if your product is sold, installed or serviced at the dealership. A general manager, service manager or parts manager can tell you who chooses what the dealership stocks and how much of that is decided by the carmaker.
Former employees are often the best sources here, because they can describe how sourcing worked without being in the middle of a live program. Keep the line clear: ask about their experience and general practice, never about a current program or confidential pricing. Expert interviews covers where that line sits.
5. A made-up example: the weld inspection startup
Here is a made-up example. A five-person startup builds a camera system that checks weld seams on stamped body parts. The founders' plan says "sell to automakers." Their spreadsheet tab is called TAM_FINAL_v4.
Reading Ford's requirements changes the plan. The product is equipment, and Ford's document says tooling and equipment suppliers to Ford cannot be certified to IATF 16949 and accepts ISO 9001 registration from them instead. That suggests a certificate is probably not the first gate, though the founders still need to ask what their tier-1 customers require. The real buyers are tier-1 stamping plants, and installing new equipment on a line is one of the listed PPAP triggers. Sizing changes too: the right number is the stamping plants in Michigan, Ohio and Indiana from County Business Patterns, not 16 million vehicles sold.
Then they book six calls: two tier-1 purchasing managers, two supplier quality engineers and two plant manufacturing engineers. The question that matters turns out to be one they had not planned: can the system run alongside the existing check for one model year, so nothing in the approved process changes until the data looks good? That answer shapes the product more than the TAM tab ever did.
Your next step
Download the customer-specific requirements for your two most likely carmakers and mark every line that applies to what you sell. Then talk to someone who has sat on the buying side of that requirement.
Instant Expert can find people matching a description such as "supplier quality engineers at tier-1 body and stamping suppliers in the Midwest," send each a paid invitation for a short call, and you pay only for calls that get booked. You set the amount each person receives, and Instant Expert's fee is added on top. Start with the directory pages for people experienced in selling to automotive OEMs, procurement professionals in automotive manufacturing and engineering professionals in automotive manufacturing.