CSLB Class A — General Engineering (Trade Exam) — All Questions

A benchmark is at 142.30 and the backsight on it reads 3.85. What is the height of instrument?

• a.142.30
• b.138.45
• c.3.85
• d.146.15✓

HI = benchmark elevation + backsight = 142.30 + 3.85 = 146.15.Leveling

The HI is 58.40 and the rod on a pipe invert reads 9.72. What is the invert elevation?

• a.49.72
• b.58.40
• c.48.68✓
• d.68.12

Elevation = HI − foresight = 58.40 − 9.72 = 48.68.Leveling

A stake reads C 1.20 and its hub is at 88.00. What is the finished grade?

• a.88.00
• b.86.80✓
• c.89.20
• d.87.20

A cut means finished grade is below the hub: 88.00 − 1.20 = 86.80.Caltrans Surveys Manual Ch. 12

What does the term "daylight" mean on grading stakes?

• a.The limit of clearing
• b.The top of a finished slope
• c.The edge of the right of way
• d.Where cut changes to fill✓

Caltrans uses daylight for the point or line of change from cut to fill or fill to cut.Caltrans Surveys Manual Ch. 12

Where must clearing and grubbing happen relative to earthwork?

• a.Before earthwork in that area✓
• b.After rough grading
• c.Only where fill will be placed
• d.Only if the engineer orders it

Caltrans requires clearing and grubbing before performing earthwork in an area.Caltrans Standard Specifications (2025) 17-2

Clods over what size must be broken up before an embankment layer is compacted?

• a.12 inches
• b.2 inches
• c.4 inches
• d.8 inches✓

Caltrans requires breaking up clods or hard lumps over 8 inches in greatest dimension before compacting.Caltrans Standard Specifications (2025) 19-6

Embankment material with 30% rock larger than 8 inches (largest 20 inches) is placed below 3 feet from finished grade. What loose layer thickness is allowed?

• a.Up to 8 inches
• b.Up to 20 inches✓
• c.Up to 12 inches
• d.Up to 36 inches

With 25 to 50 percent rock over 8 inches, the layer may not exceed the maximum rock size or 3 feet, whichever is less — here 20 inches.Caltrans Standard Specifications (2025) 19-6

In the soil descriptions FHWA uses, when is a soil designated peat?

• a.Any soil below the water table
• b.Any dark-colored soil
• c.Organic content over 50 percent✓
• d.More than 50 percent sand

FHWA designates soil with organic content of more than 50 percent as peat; dark color alone indicates possible organic soil, not peat.FHWA NHI-06-088

Which clay mineral has the highest swell potential?

• a.Montmorillonite✓
• b.Quartz
• c.Kaolinite
• d.Illite

Montmorillonite (smectite) has high swell potential; illite none to moderate; kaolinite almost none. Quartz is not a clay mineral.FHWA NHI-06-088

Wet unit weight is 119.0 pcf at 8.0% moisture. What is the dry unit weight?

• a.111.0 pcf
• b.110.2 pcf✓
• c.109.5 pcf
• d.128.5 pcf

Dry unit weight = wet ÷ (1 + w) = 119.0 ÷ 1.08 = 110.2 pcf.FHWA NHI-06-088

Field dry density is 111.6 pcf and the maximum is 120.0 pcf. What is the relative compaction?

• a.93%✓
• b.96%
• c.107.5%
• d.90%

111.6 ÷ 120.0 = 0.93, or 93%.FHWA NHI-06-088

Above optimum moisture, what usually happens as more compaction energy is applied?

• a.The fill may pump✓
• b.Density keeps rising without limit
• c.The soil dries out
• d.The optimum moisture increases

When moisture is too high for the energy, the voids saturate and the fill can pump; more energy makes it worse.FHWA NHI-06-088

A compaction specification should state which three things?

• a.Density, color and grain size
• b.Effort, density percentage and moisture range✓
• c.Effort, lift count and roller brand
• d.Moisture, weather and hauling distance

FHWA recommends stating the compaction energy, the density as a percentage of maximum, and the moisture range around optimum.FHWA NHI-06-088

What is the minimum basis for a competent person's soil classification?

• a.A single visual inspection
• b.The soils report alone
• c.At least one visual and one manual test✓
• d.A laboratory triaxial test

Cal/OSHA requires classification from at least one visual and at least one manual analysis.Cal. Code Regs. tit. 8, 1541.1 App. A

How thick may a layer of structure backfill be before compaction?

• a.0.67 foot✓
• b.1.5 feet
• c.0.25 foot
• d.2 feet

Caltrans limits structure backfill layers to 0.67 foot before compacting, except when ponding and jetting is authorized.Caltrans Standard Specifications (2025) 19-3

A benchmark is at elevation 87.46 and the backsight rod reads 4.32. What is the height of instrument?

• a.83.14
• b.91.78✓
• c.87.46
• d.4.32

The height of instrument is the known elevation plus the backsight: 87.46 + 4.32 = 91.78. Not "83.14": subtracts the backsight from the benchmark. Not "4.32": reports the rod reading rather than an elevation. Not "87.46": ignores the backsight entirely.Caltrans Surveys Manual Ch. 8

With the HI at 91.78, the rod on a catch basin invert reads 7.05. What is the invert elevation?

• a.84.73✓
• b.98.83
• c.7.05
• d.91.78

A foresight is subtracted from the HI: 91.78 - 7.05 = 84.73. Not "98.83": adds the foresight to the HI. Not "7.05": reports the rod reading as the elevation. Not "91.78": gives the HI, the elevation of the line of sight.Differential leveling

Two points are read from one level setup. The rod reads 3.10 on point P and 6.85 on point Q. Which statement is true?

• a.P and Q are at the same elevation
• b.Q is 3.75 feet higher than P
• c.Q is 3.75 feet lower than P✓
• d.Q is 9.95 feet lower than P

More rod shows below the line of sight at the lower point, so the larger reading, 6.85, is the lower point by 3.75 feet. Not "Q is 3.75 feet higher than P": a larger rod reading means a lower point. Not "Q is 9.95 feet lower than P": adds the readings instead of subtracting. Not "P and Q are at the same elevation": equal elevations would give equal readings.Differential leveling

The height of instrument is 98.60 and the design subgrade elevation is 94.50. The rod on the subgrade reads 3.80. What must be done?

• a.Cut 0.30 foot✓
• b.Fill 4.10 feet
• c.Cut 4.10 feet
• d.Fill 0.30 foot

The grade rod is 98.60 - 94.50 = 4.10; the actual rod reads 3.80, so the subgrade is 0.30 foot high and is cut. Not "Fill 0.30 foot": a small rod reading means the ground is high, not low. Not "Cut 4.10 feet": 4.10 is the grade rod reading, not the cut. Not "Fill 4.10 feet": this reverses both the direction and the amount.Differential leveling

For slope stake reference points on cuts or fills under 10 feet, what elevation setting tolerance does the Caltrans Surveys Manual give?

• a.Within 0.5 foot
• b.Within 0.01 foot
• c.Within 1.0 foot
• d.Within 0.1 foot✓

RPSS stakes are set within 1.0 foot for stationing, 0.1 foot for offset and 0.1 foot for elevation on cuts or fills under 10 feet. Not "Within 1.0 foot": that is the stationing tolerance. Not "Within 0.01 foot": tighter than the manual's figure. Not "Within 0.5 foot": not the manual's figure.Caltrans Surveys Manual Ch. 12

On a grading stake, what does the abbreviation DAY or D/L stand for?

• a.The line where cut changes to fill✓
• b.A designated lane marker
• c.The depth of the base layer
• d.The day the stake was set by the survey crew

The Surveys Manual defines daylight as the point or line of change from cut to fill, or fill to cut. Not "The depth of the base layer": base depth is shown on the typical section. Not "The day the stake was set by the survey crew": stake abbreviations carry no date. Not "A designated lane marker": lane markers are not what DAY or D/L means.Caltrans Surveys Manual Ch. 12

Which location is best for a benchmark that must last through a grading job?

• a.Next to the haul road, where the crew can reach it for easy access
• b.A stable point outside the construction area and clear of traffic✓
• c.Inside the planned excavation line, where it is easy to read each day
• d.On a stockpile near the office, so it is easy to find and use each morning

Caltrans says benchmarks should be of a stable, permanent nature and, whenever possible, outside construction areas and clear of traffic. Not "Next to the haul road, where the crew can reach it for easy access": traffic and equipment bump or bury it. Not "On a stockpile near the office, so it is easy to find and use each morning": stockpile material moves with the work. Not "Inside the planned excavation line, where it is easy to read each day": grading would remove it.Caltrans Surveys Manual Ch. 8

What is the maximum loose thickness of an embankment layer before compaction under the Caltrans earthwork specification?

• a.18 inches
• b.2 feet
• c.8 inches✓
• d.3 inches

Embankment is built in layers whose loose thickness must not exceed 8 inches. Not "2 feet": compaction equipment cannot densify a lift that thick. Not "18 inches": this is above the stated loose limit. Not "3 inches": this is thinner than the stated limit.Caltrans Standard Specifications (2025) 19-6.03C

On Caltrans clearing work, which tree branches over the roadway must be cut?

• a.Dead branches, since healthy ones may stay over the road
• b.Those hanging within 20 feet of finished grade✓
• c.Branches the engineer points out while walking the work
• d.Those within 2 feet of finished grade on the roadway side

The specification says to cut tree branches that extend over the roadway and hang within 20 feet of finished grade. Not "Dead branches, since healthy ones may stay over the road": the specification requires cutting low-hanging branches. Not "Those within 2 feet of finished grade on the roadway side": the stated clearance is far greater. Not "Branches the engineer points out while walking the work": the specification states the rule directly.Caltrans Standard Specifications (2025) 17-2.03B

Where an embankment is to receive driven piles, what is the largest rock or broken concrete allowed in the fill within the pile area?

• a.12 inches
• b.No limit if the pieces are buried
• c.8 inches
• d.4 inches or less in size✓

Where piles will be driven, the embankment material may not contain rocks or broken concrete larger than 4 inches. Not "12 inches": large pieces can deflect or damage the piles. Not "8 inches": 8 inches is the clod and layer size, not the pile-area limit. Not "No limit if the pieces are buried": buried rock would still obstruct driving.Caltrans Standard Specifications (2025) 19-6.02A

A fill's grading plane is 3 feet above original ground. In which case must stumps be removed completely rather than cut off?

• a.Where survey stakes are set along the line
• b.Where aggregate base will be placed on top of it
• c.Where pile construction is part of the work✓
• d.Where the slope will be seeded afterward

Stumps are removed completely where the work includes structure construction, pile construction, subdrainage trench excavation, removal of unsuitable material, or cutting into slopes. Not "Where aggregate base will be placed on top of it": base placement is not listed. Not "Where the slope will be seeded afterward": seeding is not listed. Not "Where survey stakes are set along the line": staking is not listed.Caltrans Standard Specifications (2025) 17-2.03C

A fill 5 feet thick is built in layers with a loose thickness of 8 inches each. At least how many layers are needed?

• a.7 layers
• b.8 layers✓
• c.15 layers
• d.5 layers

5 feet is 60 inches, and 60 divided by 8 is 7.5, which rounds up to 8 layers. Not "5 layers": treats the feet as layers. Not "7 layers": rounds 7.5 down, leaving the top short. Not "15 layers": assumes 4-inch layers.Caltrans Standard Specifications (2025) 19-6.03C

What must Caltrans work do before the new embankment is placed on an existing roadbed?

• a.Leave it as a smooth compacted plane as it stands
• b.Scarify, water, grade and roll the existing roadbed✓
• c.Cover it with a geogrid before the fill goes on
• d.Seal it with asphalt emulsion before placing the fill

The specifications direct the contractor to scarify, water, grade and roll the existing roadbed before placing new embankment on it. Not "Seal it with asphalt emulsion before placing the fill": a sealed smooth surface prevents bonding. Not "Leave it as a smooth compacted plane as it stands": a smooth plane leaves a weak contact. Not "Cover it with a geogrid before the fill goes on": geosynthetics are used only where the plans show them.Caltrans Standard Specifications (2025) 19-6.03A

Which action does Caltrans prohibit when building embankment in winter?

• a.Compacting it to the specified density
• b.Placing it in layers
• c.Watering it to reach optimum moisture
• d.Placing it when the material is frozen solid✓

Embankment is not built when the material is frozen or snow prevents proper compaction. Not "Placing it in layers": layering is required, not prohibited. Not "Compacting it to the specified density": density is the goal. Not "Watering it to reach optimum moisture": adjusting moisture is allowed.Caltrans Standard Specifications (2025) 19-6.03C

How far outside excavation and embankment slope lines (where slopes are not rounded) does Caltrans require the job site to be cleared and grubbed?

• a.2 feet, as for small ditches
• b.5 feet✓
• c.0 feet, at the slope lines
• d.50 feet

The job site is cleared and grubbed to 5 feet outside excavation and embankment slope lines where slopes are not rounded. Not "50 feet": far wider than the stated width. Not "0 feet, at the slope lines": the width extends outside the slope lines. Not "2 feet, as for small ditches": that figure applies to ditches with a bottom width under 12 feet.Caltrans Standard Specifications (2025) 17-2.03A

A sample has exactly 50 percent by weight finer than the No. 200 sieve. How does FHWA designate it?

• a.Coarse-grained
• b.Peat
• c.Organic sand
• d.Fine-grained✓

Soil with 50 percent or more by weight finer than the No. 200 sieve is fine-grained. Not "Coarse-grained": coarse-grained needs more than 50 percent of the particles larger than the sieve. Not "Peat": peat depends on organic content over 50 percent. Not "Organic sand": organic soil depends on organic matter and odor, not on sieve results.FHWA NHI-06-088

A fine soil is dried below its shrinkage limit. What happens to its volume with further drying?

• a.It becomes a liquid
• b.It swells sharply
• c.It shrinks by half over the next few days
• d.No significant change in volume occurs✓

Below the shrinkage limit, no significant change in volume occurs with additional drying. Not "It swells sharply": drying does not make it swell. Not "It shrinks by half over the next few days": shrinking stops at the shrinkage limit. Not "It becomes a liquid": that is wetting, past the liquid limit.FHWA NHI-06-088

In a Standard Penetration Test, what is the first 6-inch increment of driving considered?

• a.A seating penetration, not counted in N✓
• b.The N-value by itself, with no other increments added in
• c.The refusal depth of the sampler in dense soil
• d.The liquid limit of the soil that was sampled

The first recorded increment is considered a seating penetration; the second and third increments give the N-value. Not "The N-value by itself, with no other increments added in": N is the blows for the second and third increments. Not "The liquid limit of the soil that was sampled": that is an Atterberg limit, not a driving record. Not "The refusal depth of the sampler in dense soil": refusal is a separate condition.FHWA NHI-06-088

What is the unconfined compressive strength range of Cal/OSHA Type B cohesive soil?

• a.More than 0.5 tsf but less than 1.5 tsf✓
• b.1.5 tsf or more, for the stiffest clays and hardpan
• c.0.5 tsf or less, for soft and very wet cohesive soil
• d.Over 4.0 tsf, as for hard rock that holds a vertical face

Type B cohesive soil is above 0.5 and below 1.5 tsf. Not "1.5 tsf or more, for the stiffest clays and hardpan": that range is for Type A, subject to the disqualifiers. Not "0.5 tsf or less, for soft and very wet cohesive soil": that range is Type C. Not "Over 4.0 tsf, as for hard rock that holds a vertical face": no Type B range reaches that value.Cal. Code Regs. tit. 8, 1541.1 App. A

Which soil is Type C under Cal/OSHA's classification?

• a.Submerged soil or soil with water freely seeping from it✓
• b.Dry rock that is stable and holds a vertical face when cut
• c.Unfissured cohesive soil that is over 1.5 tsf in strength
• d.Cohesive soil between 0.5 and 1.5 tsf in unconfined strength

Type C includes cohesive soil of 0.5 tsf or less, gravel, sand and loamy sand, and submerged or freely seeping soil. Not "Unfissured cohesive soil that is over 1.5 tsf in strength": that strength is Type A, absent disqualifiers. Not "Dry rock that is stable and holds a vertical face when cut": stable rock has its own category. Not "Cohesive soil between 0.5 and 1.5 tsf in unconfined strength": that strength is Type B.Cal. Code Regs. tit. 8, 1541.1 App. A

Which condition keeps otherwise strong cohesive soil from being classified Type A?

• a.The soil is brown or tan in color when it is dug
• b.The soil is dry on the surface of the trench wall
• c.The soil is fissured or subject to vibration✓
• d.The trench is under 10 feet deep at the point of entry

No soil is Type A if it is fissured, subject to vibration from heavy traffic or pile driving, or previously disturbed. Not "The soil is dry on the surface of the trench wall": a dry surface does not disqualify Type A. Not "The soil is brown or tan in color when it is dug": color is not a factor. Not "The trench is under 10 feet deep at the point of entry": depth is not a Type A disqualifier.Cal. Code Regs. tit. 8, 1541.1 App. A

A competent person classified a trench wall as Type B at 7 a.m. After a heavy rain at noon, seepage appears. What must happen?

• a.The changed conditions are evaluated and the soil is reclassified✓
• b.The morning classification stands for the whole day
• c.The trench is classified Type A because the wall has become wet and sticky
• d.Work stops permanently on the project, because the soil has failed

If properties or conditions change after classification, the changes are evaluated and the deposit reclassified. Not "The morning classification stands for the whole day": the rule requires reevaluation when conditions change. Not "The trench is classified Type A because the wall has become wet and sticky": wet soil is less stable, not more. Not "Work stops permanently on the project, because the soil has failed": nothing so extreme is required.Cal. Code Regs. tit. 8, 1541.1 App. A

Which statement about Cal/OSHA's soil classification is correct?

• a.It is made once by the geotechnical engineer for the whole job
• b.It may be made by estimate from a distance
• c.It follows the USCS group symbol exactly
• d.It must rest on at least one visual and one manual analysis✓

Appendix A requires classification by a competent person based on at least one visual and one manual analysis. Not "It may be made by estimate from a distance": visual analysis alone is not enough. Not "It is made once by the geotechnical engineer for the whole job": the competent person classifies the deposits on site. Not "It follows the USCS group symbol exactly": Cal/OSHA's types are a separate system.Cal. Code Regs. tit. 8, 1541.1 App. A

Which test is named among the field methods to estimate unconfined compressive strength in Cal/OSHA's soil classification appendix?

• a.Proctor hammer drops on a sample
• b.Thumb penetration✓
• c.Sieve shake test of the fines
• d.Slump cone

Appendix A says strength can be estimated in the field using a pocket penetrometer, by thumb penetration tests and other methods. Not "Slump cone": a slump cone tests concrete. Not "Proctor hammer drops on a sample": a Proctor test is a laboratory compaction test. Not "Sieve shake test of the fines": sieving measures grain size, not strength.Cal. Code Regs. tit. 8, 1541.1 App. A

On a compaction curve, what does the peak represent?

• a.The liquid limit, where the soil begins to flow
• b.The maximum dry density, at the optimum moisture content✓
• c.The wet density at the shrinkage limit
• d.The minimum density the soil can reach after compaction

The peak of dry unit weight against moisture is the maximum dry density and its moisture is the optimum. Not "The wet density at the shrinkage limit": the curve plots dry density against moisture. Not "The minimum density the soil can reach after compaction": the peak is the highest, not the lowest. Not "The liquid limit, where the soil begins to flow": the liquid limit is an Atterberg limit, not a compaction point.FHWA NHI-06-088

Compared with the Standard Proctor test, how much more energy does the Modified Proctor test apply?

• a.About 10 times
• b.About the same
• c.About half
• d.About 4.5 times✓

FHWA states the Modified Proctor energy is 4.5 times the Standard Proctor energy. Not "About the same": the energy levels differ. Not "About half": the modified test has higher energy. Not "About 10 times": this exceeds the stated ratio.FHWA NHI-06-088 Table 5-13

What does the dry unit weight of a soil measure, according to FHWA?

• a.The temperature of the soil when compacted
• b.The amount of water in a unit volume of soil
• c.The amount of solid materials in a unit volume of soil✓
• d.The size of the largest stone

The dry unit weight is a measure of the amount of solid materials present in a unit volume of soil. Not "The amount of water in a unit volume of soil": that describes moisture content. Not "The temperature of the soil when compacted": temperature is not what it measures. Not "The size of the largest stone": stone size is a gradation property.FHWA NHI-06-088

A clay with desiccation cracks at the surface suggests what concern?

• a.Too little organic content
• b.Expansion and shrinkage with wet and dry cycles✓
• c.Liquefaction in a dry season
• d.Excess coarse gravel mixed into the clay layer near the surface

FHWA notes surface desiccation cracks and fissures in a clay deposit indicate expansion potential. Not "Liquefaction in a dry season": liquefaction needs saturated, loose granular soil. Not "Too little organic content": cracking does not point to organic content. Not "Excess coarse gravel mixed into the clay layer near the surface": cracks form in clay, not gravel.FHWA NHI-06-088

Which clay mineral is described as having almost no swell?

• a.Silica
• b.Kaolinite✓
• c.Smectite
• d.Montmorillonite

FHWA says kaolinite exhibits almost no swell, illite no to moderate, and montmorillonite a high degree. Not "Montmorillonite": it has a high degree of swell potential. Not "Smectite": it is another name for the high-swell montmorillonite group. Not "Silica": silica is not a clay mineral.FHWA NHI-06-088

Caltrans accepts compaction of aggregate base by which test method?

• a.California Test 231✓
• b.California Test 202
• c.California Test 216
• d.A slump cone test

Aggregate base compaction is tested under California Test 231; California Test 216 gives optimum moisture and California Test 202 gradation. Not "California Test 216": that test determines optimum moisture content. Not "California Test 202": that test is used for aggregate gradation. Not "A slump cone test": slump is a concrete test.Caltrans Standard Specifications (2025) 26-1.01D(3)