C-12 Earthwork and Paving exam questions, with answers
10 practice questions for the CSLB Earthwork and Paving trade exam, each with the answer, a plain explanation and the source it rests on.
These are not real exam questions. CSLB does not release its test questions or answer keys, and nobody else has them. We write our own questions from the C-12 outline and the codes, standards and references CSLB lists for the exam. Each answer names its source so you can check it.
The C-12 exam has 4 sections. The questions below are grouped by section, with the share of the exam each one carries. Read the question, pick an answer, then open “Show the answer”. The other questions of the free test, scored section by section, are in the free 25-question C-12 test.
Planning and Estimating · 20% of the exam
Plans and specifications; job site conditions; estimating; project layout; materials and equipment.
1. On a project under the Caltrans Standard Specifications, a plan sheet shows an inlet pad with the note "8 ft" beside it, but the pad scales to 9 ft with your ruler. Under Section 5-1.02, which size governs?
- The noted 8 ft, because written numbers govern over graphics
- The larger 9 ft, because the bigger size is the safer reading
- The average 8.5 ft, because the two readings carry equal rank
- The scaled 9 ft, because graphics govern over written notes
Show the answer
Answer: A. Section 5-1.02 of the Caltrans Standard Specifications settles this kind of discrepancy: written numbers and notes on a drawing govern over graphics. Scaling a drawing does not override the number written on it, and the section gives no preference to the larger size or to an average.
Source: Caltrans Standard Specifications (2025), Section 5-1.02
2. You must haul away all the soil from a building pad cut 120 ft by 80 ft by 3 ft deep. The soil is loam with a bank-to-loose factor of 1.25 (US Army FM 5-434), and each truck carries 14 loose cu yd. How many truckloads must you schedule, rounding up to a whole load?
- 61 loads
- 77 loads
- 95 loads
- 96 loads
Show the answer
Answer: D. The cut is 120 x 80 x 3 = 28,800 cu ft, and 28,800 / 27 = 1,066.7 bank cu yd. Multiplying by 1.25 gives 1,333.3 loose cu yd, as FM 5-434 converts bank to loose. At 14 cu yd per truck that is 95.2, so 96 loads. Skipping the swell gives 77, and dividing by 1.25 gives 61.
Source: FM 5-434, Table 1-1 (loam, bank to loose 1.25), US Army FM 5-434, Earthmoving Operations (2000)
Earthwork and Grade Control · 29% of the exam
Grade control; soils and geology; excavation and trenching; fill and grading.
3. From a bench mark at elevation 412.35 ft you read a backsight of 5.62 ft, then a foresight of 2.18 ft on a turning point. After moving the level you read a backsight of 6.04 ft on that turning point and a foresight of 3.47 ft on a hub. Height of instrument = known elevation + backsight. What is the elevation of the hub?
- 406.34 ft
- 414.50 ft
- 418.36 ft
- 421.83 ft
Show the answer
Answer: C. The first height of instrument is 412.35 + 5.62 = 417.97 ft, so the turning point is 417.97 - 2.18 = 415.79 ft. The second height of instrument is 415.79 + 6.04 = 421.83 ft, so the hub is 421.83 - 3.47 = 418.36 ft. Stopping at 421.83 forgets the last foresight, 414.50 skips the turning point, and 406.34 swaps the signs. This is the leveling method in the USDA Engineering Field Manual.
4. Your level run must cross soft ground, so the rod person needs a turning point there before you move the instrument. According to the Caltrans Surveys Manual, which turning point is the right choice?
- A wooden stake driven to a firm depth, with a marked point for the rod
- A loose rock on the surface, chosen so it can be carried off after use
- A painted spot on soft soil, chosen so the rod returns to the same place
- The bucket of a parked loader, chosen since its weight keeps it in place
Show the answer
Answer: A. The Caltrans Surveys Manual (8.2-2) says turning points should be set in stable, protected locations, with a definite high point or a marked point of rod contact. In soft ground it calls for a long wooden stake driven to a firm depth. A turning point that moves between the foresight and the next backsight carries an error into every later elevation.
5. While digging a test pit under a planned building pad, your crew hits a dark, somewhat fibrous layer of decayed plant matter with a strong odor. According to the soil descriptions in UFC 3-220-10, how should this layer be treated?
- As silt, slightly compressible and suitable to support foundations
- As fat clay, very expansive but suitable to support foundations
- As loose sand, slightly compressible and suitable after it is rolled
- As peat, very compressible and unsuitable to support foundations
Show the answer
Answer: D. UFC 3-220-10 describes peat as a somewhat fibrous mass of decayed vegetation with a dark color and an odor of decay. It calls peat very compressible and entirely unsuitable for supporting building foundations. Tell the soils engineer before grading goes ahead; do not treat the layer as ordinary clay, silt or sand.
Source: UFC 3-220-10, Chapter 1, soil descriptions: peats, UFC 3-220-10, Soil Mechanics (2022)
Paving · 30% of the exam
Roadways, driveways and parking lots; ADA requirements; specialty paving; demolition and pavement repair; related paving activities.
6. On a project under the Caltrans Standard Specifications, your crew has just finished rolling new HMA in a lane closure, and the traffic control lead wants to reopen the lane. Under Section 39-2.01C(15), what temperature condition must the new pavement meet first?
- Surface temperature below 160°F
- Mid depth temperature below 160°F
- Surface temperature below 120°F
- Mid depth temperature below 200°F
Show the answer
Answer: B. Section 39-2.01C(15)(a) says not to open new HMA pavement to traffic until its mid depth temperature is below 160°F. The surface cools first, so a surface reading can look fine while the middle of the mat is still soft enough to rut under traffic.
Source: Caltrans Standard Specifications (2025), Section 39-2.01C(15)(a)
7. On a project under the Caltrans Standard Specifications, the plans show 0.70 ft of aggregate base (AB) under a new road. Under Sections 26-1.03D and 26-1.03E, how must your crew spread and compact it?
- A single 0.70-ft layer, compacted to at least 95 percent with more passes
- At least 2 about equal layers, each compacted to at least 90 percent
- At least 2 about equal layers, each compacted to at least 95 percent
- A 0.20-ft bottom and a 0.50-ft top layer, with only the top at 95 percent
Show the answer
Answer: C. Section 26-1.03D says AB thicker than 0.50 ft goes down in at least 2 approximately equal layers, with no single compacted layer over 0.50 ft. Section 26-1.03E then requires each AB layer to reach at least 95 percent relative compaction. Extra roller passes do not replace the layer limit, and every layer has to meet the density.
Source: Caltrans Standard Specifications (2025), Sections 26-1.03D and 26-1.03E
8. You are laying out joints for a new concrete sidewalk on a project under the Caltrans Standard Specifications. Under Section 73-3.03, contraction joints must divide the surface into rectangular patterns of what size?
- 12 to 20 sq ft
- 24 to 36 sq ft
- 40 to 60 sq ft
- 64 to 80 sq ft
Show the answer
Answer: A. Section 73-3.03 calls for contraction joints that create rectangular patterns from 12 to 20 sq ft in the surface of sidewalks. The same section sets expansion joints at returns, opposite expansion joints in the adjacent curb, and at 60-ft intervals where there is no adjacent curb. Larger panels would leave the concrete free to crack between joints.
Source: Caltrans Standard Specifications (2025), Section 73-3.03
Safety · 21% of the exam
Job site safety; environmental impact; traffic control.
9. Your paving company keeps one generic Code of Safe Practices, copied from a sample and filed at the main office, and your new job site has none. According to the Cal/OSHA Pocket Guide for the Construction Industry (citing Title 8 §1509), what must change?
- It must fit your operations and be posted or readily available at the job site
- It must fit your operations and be mailed to Cal/OSHA before the job site opens
- It may stay generic but be posted or readily available at the job site
- It may stay generic and be filed at the office if the crew signs for it
Show the answer
Answer: A. The Cal/OSHA Pocket Guide, citing Title 8 §1509(b) and (c), says the written Code of Safe Practices must be specific to the employer's operations. It must be posted at each job site office or be readily available at the job site. The sample code is only a starting point, and a copy kept at the main office does not meet the rule.
Source: Cal/OSHA Pocket Guide (July 2022), Code of Safe Practices, citing 8 CCR §1509(b), (c)
10. You are ordering advance warning signs for a roadwork zone on a county road. Under Section 6H.01 of the California MUTCD (2026), what shape and colors must ordinary temporary traffic control warning signs have?
- Diamond, with white legend and border on orange
- Diamond, with black legend and border on white
- Diamond, with black legend and border on orange
- Rectangle, with black legend and border on orange
Show the answer
Answer: C. Section 6H.01 of the California MUTCD (2026) says TTC warning signs shall be diamond-shaped with a black legend and border on an orange or fluorescent orange background, with narrow listed exceptions. The orange tells drivers the condition is temporary and work-related.
Where to go from here
How the license works, from experience to fees: how to get a C-12 license. Everything about the course: the C-12 exam page.
Questions from our free C-12 test, written from CSLB License Examination Study Guide, Earthwork and Paving (C-12), form 13E-12 (03-2026), for examinations scheduled on or after September 1, 2023. CSLB notes that the percentages are approximate. Reviewed 14 October 2026. Study guidance only; we are not affiliated with CSLB or PSI.