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