# Bus and Truck Mechanics and Diesel Engine Specialists

US SOC code 49-3031. Markdown version of https://futurehistory.earth/timeline/49-3031

Also called: Diesel mechanic, Diesel technician, Heavy-duty mechanic, Fleet mechanic, Truck mechanic.

## In brief

In May 2025, [BLS](https://www.bls.gov/oes/special-requests/oesm25nat.zip) counted **289,960** US bus and truck mechanics and diesel engine specialists, with median pay of **$61,770** a year. Of the BLS counts since 2003, the May 2025 count is the highest. The earliest figure here is [an estimate](https://en.wikipedia.org/wiki/History_of_the_trucking_industry_in_the_United_States) of **35,000** from 1930, not measured the same way as today's count. The last full technology era in this work: Telematics + predictive maintenance, 2015 to 2023. Predictive maintenance raised shop throughput without adding headcount.

## What the sources say

### Official outlook

BLS projects employment to grow 3.6% from 2025 to 2035. Source: [BLS Employment Projections 2025-35](https://data.bls.gov/projections/nationalMatrix?queryParams=49-3031&ioType=o).

### AI exposure studies

- **0%** of this job's tasks are exposed to large language models. Not a forecast of job losses. [Eloundou and others, 2023](https://github.com/openai/GPTs-are-GPTs/blob/main/data/occ_level.csv)
- **0.73** estimated probability that the whole occupation could be computerised, over an unspecified number of years. Not a forecast of job losses. [Frey and Osborne, 2013](https://oms-www.files.svdcdn.com/production/downloads/academic/The_Future_of_Employment.pdf)

### Since the 2013 prediction

In 2013, Frey and Osborne put this job's probability of computerisation at 0.73. BLS counted **238,150** of these jobs in May 2013 and **289,960** in May 2025 (+22%, a change derived by Future History).

Data as of BLS OEWS May 2025; BLS Employment Projections 2025-35. BLS publishes these counts as yearly survey snapshots and cautions against reading them as a precise trend. In May 2021 BLS changed how it estimates these counts (a model-based method using three years of survey data) and moved fully to the 2018 occupation codes, so part of a change across 2021 can come from the method rather than the work.

## Bus and Truck Mechanics and Diesel Engine Specialists employment and pay by year

- On record since: 1900
- Latest US employment: 289,960 (May 2025). Source: BLS OEWS May 2025 [6]
- Latest US median pay: $61,770 (May 2025). Source: BLS OEWS May 2025 [10]
- Outlook: +3.6% by 2035. Source: BLS Employment Projections 2025-35 [25]

### All 30 years of cited US data

| Year | US employment | Annual pay (median unless marked) | Source |
| --- | --- | --- | --- |
| 1930 | 35,000 (estimate) | n/a | Est., Wikipedia [1] |
| 1950 | 125,000 (estimate) | n/a | Est., Detroit Diesel Series 71 [2] |
| 1959 | n/a | $5,200 | BLS historical bulletin 1959 [7] |
| 1969 | n/a | $8,100 | BLS historical bulletin [8] |
| 1970 | 195,000 (estimate) | n/a | Est., Association of Diesel Specialists (ADS) [3] |
| 1990 | 248,000 (estimate) | n/a | Est., Motor Carrier Act of 1980 [4] |
| 2000 | 258,800 | $32,350 | BLS OEWS 2000 [5] |
| 2003 | 248,450 | $34,970 | BLS OEWS May 2003 [6] |
| 2004 | 251,430 | $35,780 | BLS OEWS May 2004 [6] |
| 2005 | 248,280 | $36,620 | BLS OEWS May 2005 [6] |
| 2006 | 254,850 | $37,660 | BLS OEWS May 2006 [6] |
| 2007 | 250,370 | $38,640 | BLS OEWS May 2007 [6] |
| 2008 | 248,620 | $39,390 | BLS OEWS May 2008 [6] |
| 2009 | 232,810 | $40,250 | BLS OEWS May 2009 [6] |
| 2010 | 222,770 | $40,850 | BLS OEWS May 2010 [6] |
| 2011 | 222,940 | $41,640 | BLS OEWS May 2011 [6] |
| 2012 | 230,030 | $42,320 | BLS OEWS May 2012 [6] |
| 2013 | 238,150 | $42,730 | BLS OEWS May 2013 [6] |
| 2014 | 243,080 | $43,630 | BLS OEWS May 2014 [6] |
| 2015 | 251,750 | $44,520 | BLS OEWS May 2015 [6] |
| 2016 | 254,280 | $45,170 | BLS OEWS May 2016 [6] |
| 2017 | 260,380 | $46,360 | BLS OEWS May 2017 [6] |
| 2018 | 264,860 | $47,350 | BLS OEWS May 2018 [6] |
| 2019 | 266,330 | $48,500 | BLS OEWS May 2019 [6] |
| 2020 | 253,010 | $50,200 | BLS OEWS May 2020 [6] |
| 2021 | 261,420 | $48,690 | BLS OEWS May 2021 [6] |
| 2022 | 271,720 | $54,360 | BLS OEWS May 2022 [6] |
| 2023 | 285,030 | $58,970 | BLS OEWS May 2023 [6] |
| 2024 | 287,230 | $60,640 | BLS OEWS May 2024 [6] |
| 2025 | 289,960 | $61,770 | BLS OEWS May 2025 [6] |

## Sources (91)

### Employment series

1. [History of the Trucking Industry in the United States (Wikipedia) — 1920s-1930s truck fleet and workforce context](https://en.wikipedia.org/wiki/History_of_the_trucking_industry_in_the_United_States), Wikipedia
2. [Detroit Diesel Series 71 — Wikipedia (WWII production context and post-war workforce)](https://en.wikipedia.org/wiki/Detroit_Diesel_Series_71), Wikipedia
3. [Association of Diesel Specialists (ADS) — founding and history (1956, Chicago)](https://www.centraldieselinc.com/blog/ads-international-convention/), Central Diesel Inc.
4. [Motor Carrier Act of 1980 — Wikipedia (deregulation effects: fleet expansion, employment growth)](https://en.wikipedia.org/wiki/Motor_Carrier_Act_of_1980), Wikipedia
5. [BLS OES 2000 national estimates (flat file)](https://www.bls.gov/oes/special-requests/oes00nat.zip), Bureau of Labor Statistics
6. BLS OEWS, national cross-industry estimates (flat file), Bureau of Labor Statistics. Editions: [2003](https://www.bls.gov/oes/special-requests/oesm03nat.zip), [2004](https://www.bls.gov/oes/special-requests/oesm04nat.zip), [2005](https://www.bls.gov/oes/special-requests/oesm05nat.zip), [2006](https://www.bls.gov/oes/special-requests/oesm06nat.zip), [2007](https://www.bls.gov/oes/special-requests/oesm07nat.zip), [2008](https://www.bls.gov/oes/special-requests/oesm08nat.zip), [2009](https://www.bls.gov/oes/special-requests/oesm09nat.zip), [2010](https://www.bls.gov/oes/special-requests/oesm10nat.zip), [2011](https://www.bls.gov/oes/special-requests/oesm11nat.zip), [2012](https://www.bls.gov/oes/special-requests/oesm12nat.zip), [2013](https://www.bls.gov/oes/special-requests/oesm13nat.zip), [2014](https://www.bls.gov/oes/special-requests/oesm14nat.zip), [2015](https://www.bls.gov/oes/special-requests/oesm15nat.zip), [2016](https://www.bls.gov/oes/special-requests/oesm16nat.zip), [2017](https://www.bls.gov/oes/special-requests/oesm17nat.zip), [2018](https://www.bls.gov/oes/special-requests/oesm18nat.zip), [2019](https://www.bls.gov/oes/special-requests/oesm19nat.zip), [2020](https://www.bls.gov/oes/special-requests/oesm20nat.zip), [2021](https://www.bls.gov/oes/special-requests/oesm21nat.zip), [2022](https://www.bls.gov/oes/special-requests/oesm22nat.zip), [2023](https://www.bls.gov/oes/special-requests/oesm23nat.zip), [2024](https://www.bls.gov/oes/special-requests/oesm24nat.zip), [2025](https://www.bls.gov/oes/special-requests/oesm25nat.zip)

### Wage series

7. [U.S. Bureau of Labor Statistics — Occupational Outlook Handbook, 1959 Edition (Bulletin No. 1255), mechanic annual earnings](https://fraser.stlouisfed.org/title/occupational-outlook-handbook-3964/occupational-outlook-handbook-1959-edition-495782/fulltext), U.S. Bureau of Labor Statistics
8. [U.S. Bureau of Labor Statistics — Area Wage Survey: Metropolitan Areas, United States and Regional Summaries, 1969-70 (Bulletin No. 1660-92), mechanics and repairmen earnings](https://fraser.stlouisfed.org/title/area-wage-survey-4655/area-wage-survey-metropolitan-areas-united-states-regional-summaries-1969-70-498645/fulltext), U.S. Bureau of Labor Statistics
9. [BLS OES 2000 national estimates (flat file)](https://www.bls.gov/oes/special-requests/oes00nat.zip), Bureau of Labor Statistics
10. BLS OEWS, national cross-industry estimates (flat file), Bureau of Labor Statistics. Editions: [2003](https://www.bls.gov/oes/special-requests/oesm03nat.zip), [2004](https://www.bls.gov/oes/special-requests/oesm04nat.zip), [2005](https://www.bls.gov/oes/special-requests/oesm05nat.zip), [2006](https://www.bls.gov/oes/special-requests/oesm06nat.zip), [2007](https://www.bls.gov/oes/special-requests/oesm07nat.zip), [2008](https://www.bls.gov/oes/special-requests/oesm08nat.zip), [2009](https://www.bls.gov/oes/special-requests/oesm09nat.zip), [2010](https://www.bls.gov/oes/special-requests/oesm10nat.zip), [2011](https://www.bls.gov/oes/special-requests/oesm11nat.zip), [2012](https://www.bls.gov/oes/special-requests/oesm12nat.zip), [2013](https://www.bls.gov/oes/special-requests/oesm13nat.zip), [2014](https://www.bls.gov/oes/special-requests/oesm14nat.zip), [2015](https://www.bls.gov/oes/special-requests/oesm15nat.zip), [2016](https://www.bls.gov/oes/special-requests/oesm16nat.zip), [2017](https://www.bls.gov/oes/special-requests/oesm17nat.zip), [2018](https://www.bls.gov/oes/special-requests/oesm18nat.zip), [2019](https://www.bls.gov/oes/special-requests/oesm19nat.zip), [2020](https://www.bls.gov/oes/special-requests/oesm20nat.zip), [2021](https://www.bls.gov/oes/special-requests/oesm21nat.zip), [2022](https://www.bls.gov/oes/special-requests/oesm22nat.zip), [2023](https://www.bls.gov/oes/special-requests/oesm23nat.zip), [2025](https://www.bls.gov/oes/special-requests/oesm25nat.zip)
11. [BLS OEWS May 2024, national cross-industry estimates (flat file)](https://www.bls.gov/oes/special-requests/oesm24nat.zip), U.S. Bureau of Labor Statistics

### Tool eras

12. [History of the Trucking Industry in the United States (Wikipedia) — early fleet maintenance context](https://en.wikipedia.org/wiki/History_of_the_trucking_industry_in_the_United_States), Wikipedia
13. [Automotive History Day — First Diesel Road Trip, January 6, 1930 (Cummins Model U Diesel in Packard, 792 miles for $1.38)](https://automotivehistory.org/first-diesel-road-trip/), This Day in Automotive History
14. [Detroit Diesel Series 71 — Wikipedia (founding 1938, WWII production 57,892 units in 1943, Series history)](https://en.wikipedia.org/wiki/Detroit_Diesel_Series_71), Wikipedia
15. [Association of Diesel Specialists — About ADS (founded 1956, Chicago, 21 founding members; commercial diesel service industry history)](https://www.centraldieselinc.com/blog/ads-international-convention/), Central Diesel Inc. / ADS
16. [ASE Celebrates 50 Years — Work Truck Online (founded 1972; "mechanic" to "technician" shift in 1982; T-Series truck certifications)](https://www.worktruckonline.com/articles/certified-history-ase-celebrates-50-years), Work Truck Online / ASE
17. [Automotive Service Excellence — Wikipedia (founding, mission, 225,000 certified professionals)](https://en.wikipedia.org/wiki/Automotive_Service_Excellence), Wikipedia
18. [On-Board Diagnostics — Wikipedia (OBD-II timeline: 1994 phase-in, mandatory 1996 for gasoline, 1997 for diesel; J1939 heavy truck protocol)](https://en.wikipedia.org/wiki/On-board_diagnostics), Wikipedia
19. [Diesel Emission Standards — 4BT Engines (EPA 1990s-2000s NOx/PM phase-in, EGR technology mandate for 2004 engines)](https://4btengines.com/the-history-of-diesel-emission-standards/), 4BT Engines
20. [EPA 2007 Diesel Emission Standards — One Year Later: Implications for Fleet Operators (Work Truck Online)](https://www.worktruckonline.com/articles/one-year-later-2007-diesel-emission-standards-implications-for-fleet-operators), Work Truck Online
21. [Fleet Maintenance magazine — Preteckt: How AI Can Empower Diagnostic Technicians (90% fault-code noise reduction; 60%+ diagnostic productivity gain)](https://www.fleetmaintenance.com/shop-operations/article/53042552/preteckt-how-ai-can-empower-diagnostic-technicians), Fleet Maintenance
22. [Service Truck Magazine — AI Is Powering a New Era in Truck Maintenance (Samsara, Geotab, Jaltest CV)](https://www.servicetruckmagazine.com/news/ai-is-powering-a-new-era-in-truck-maintenance/), Service Truck Magazine
23. [Robotics and Automation News (Apr 2026) — What Skills Will Truck Techs Need in the AI Era? (70%+ weekly AI tool use; CAN bus, data logging, cybersecurity as foundational skills)](https://roboticsandautomationnews.com/2026/04/01/what-skills-will-truck-techs-need-in-the-ai-era/100333/), Robotics and Automation News
24. [Fleet Equipment Magazine — Kenworth Launches EV Technician Training and Certification Program (seven-course curriculum)](https://www.fleetequipmentmag.com/kenworth-ev-technician-training/), Fleet Equipment Magazine

### Forecasts and exposure studies

25. [BLS Employment Projections 2025-35, National Employment Matrix: 49-3031 Bus and truck mechanics and diesel engine specialists (2025: 316.0 thousand; 2035: 327.4 thousand; +3.6%)](https://data.bls.gov/projections/nationalMatrix?queryParams=49-3031&ioType=o), Bureau of Labor Statistics
26. [Frey & Osborne (2013), "The Future of Employment: How Susceptible Are Jobs to Computerisation?", Appendix (SOC 49-3031 Bus and Truck Mechanics and Diesel Engine Specialists: probability 0.73, rank 404 of 702)](https://oms-www.files.svdcdn.com/production/downloads/academic/The_Future_of_Employment.pdf), Oxford Martin School, University of Oxford
27. [Eloundou, Manning, Mishkin & Rock (2023), "GPTs are GPTs", occupation-level exposure data occ\_level.csv (O\*NET-SOC 49-3031.00, human-rated β 0)](https://github.com/openai/GPTs-are-GPTs/blob/main/data/occ_level.csv), OpenAI

### Historical notes

28. [Daimler Truck — "The World's First Ever Diesel Trucks from Benz and Daimler in 1923" (press release, 100th anniversary)](https://www.daimlertruck.com/en/newsroom/pressrelease/the-worlds-first-ever-diesel-trucks-from-benz-and-daimler-in-1923-50057802), Daimler Truck
29. [This Day in Automotive History — "The First Diesel Road Trip" (January 6, 1930; Cummins Indianapolis to New York, $1.38 fuel cost)](https://automotivehistory.org/first-diesel-road-trip/), This Day in Automotive History
30. [Detroit Diesel Series 71 — Wikipedia (introduced 1938; WWII production; continued until 1995)](https://en.wikipedia.org/wiki/Detroit_Diesel_Series_71), Wikipedia
31. [Central Diesel Inc. — "A Background of ADS and the ADS International Convention" (ADS founding 1956, 21 Chicago attendees)](https://www.centraldieselinc.com/blog/ads-international-convention/), Central Diesel Inc.
32. [ASE Celebrates 50 Years — Work Truck Online (founded June 12, 1972; T-Series truck certifications; "technician" terminology shift 1982)](https://www.worktruckonline.com/articles/certified-history-ase-celebrates-50-years), Work Truck Online / ASE
33. [Motor Carrier Act of 1980 — Wikipedia (operating authorities doubled 1980-1990; driver employment growth)](https://en.wikipedia.org/wiki/Motor_Carrier_Act_of_1980), Wikipedia
34. [Diesel Emission Standards — 4BT Engines (PM standard 0.01 g/bhp-hr in 2007; 100% DPF mandate; SCR for 2010 NOx)](https://4btengines.com/the-history-of-diesel-emission-standards/), 4BT Engines
35. [Heavy Duty Journal — Diesel Mechanic Shortage: 177,000 new entrants needed 2022-2026, fewer than 11,000 graduating annually](https://heavydutyjournal.com/diesel-mechanic-shortage-impact-labor-market-trends-and-workforce-solutions/), Heavy Duty Journal

### Predecessors & successors

36. [History of the Trucking Industry in the United States — Wikipedia (early truck mechanics, pre-1930s)](https://en.wikipedia.org/wiki/History_of_the_trucking_industry_in_the_United_States), Wikipedia
37. [Detroit Diesel Series 71 — Wikipedia (WWII production: 57,892 engines in 1943; military mechanics transitioned to civilian shops post-war)](https://en.wikipedia.org/wiki/Detroit_Diesel_Series_71), Wikipedia

### Present-day analysis

- [O\*NET 30.3 -- Bus and Truck Mechanics and Diesel Engine Specialists (49-3031.00)](https://www.onetonline.org/link/summary/49-3031.00), accessed 2026-06-03
- [Frey & Osborne 2013 -- "The Future of Employment": Automotive Mechanics probability of computerization 0.29](https://oms-www.files.svdcdn.com/production/downloads/academic/The_Future_of_Employment.pdf), accessed 2026-06-03
- [Eloundou et al. 2024 -- GPTs are GPTs (Science): core repair tasks are physical/sensory with very low LLM exposure](https://arxiv.org/abs/2303.10130), accessed 2026-06-03
- [Heavy Duty Journal -- Diesel Mechanic Shortage: 177,000 new entrants needed 2022-2026, \<11,000 graduating annually](https://heavydutyjournal.com/diesel-mechanic-shortage-impact-labor-market-trends-and-workforce-solutions/), accessed 2026-06-03
- [Robotics & Automation News (Apr 2026) -- over 70% of truck techs now use AI-powered diagnostics every week](https://roboticsandautomationnews.com/2026/04/01/what-skills-will-truck-techs-need-in-the-ai-era/100333/), accessed 2026-06-03
- [Fleet Maintenance -- Preteckt AI improves diagnostic productivity 60%+; reduced monthly fault-code noise 90% for 100-bus fleet](https://www.fleetmaintenance.com/shop-operations/article/53042552/preteckt-how-ai-can-empower-diagnostic-technicians), accessed 2026-06-03
- [Cummins -- Optimized Diagnostics: Guidanz + QuickServe + INSITE streamline engine root-cause identification](https://www.cummins.com/en-na/news/2024/05/28/optimized-diagnostics-explained), accessed 2026-06-03
- [Service Truck Magazine -- AI is powering a new era in truck maintenance (Jaltest CV, Samsara, Geotab)](https://www.servicetruckmagazine.com/news/ai-is-powering-a-new-era-in-truck-maintenance/), accessed 2026-06-03
- [Trucking Info -- How AI Is Transforming Truck Maintenance (technician-to-tool ratio: 6:1 in 2016, 2.5:1 in 2025)](https://www.truckinginfo.com/digital-cover-features/how-ai-is-transforming-truck-maintenance), accessed 2026-06-03
- [Fleetequipmentmag.com -- Kenworth launches EV technician training and certification program](https://www.fleetequipmentmag.com/kenworth-ev-technician-training/), accessed 2026-06-03
- [ShopView -- AI-powered diesel diagnostics cut diagnostic time by 60% or more](https://shopview.com/blog/ai-powered-diesel-diagnostics-for-heavy-duty-repair), accessed 2026-06-03

How to read these figures: https://futurehistory.earth/methodology. Every figure links to its own source; gaps stay gaps.