CSLB C-12 Earthwork and Paving (Trade Exam) — All Questions

What is the minimum thickness of each lift when Type A hot mix is placed in multiple lifts?

• a.0.15 foot✓
• b.0.05 foot
• c.0.30 foot
• d.0.50 foot

When the thickness shown is 0.30 foot or more, multiple lifts of not less than 0.15 foot each are allowed. Thinner lifts cool too quickly, 0.30 foot is the total thickness threshold, and 0.50 foot is the aggregate base layer limit.Caltrans 2024 Standard Specifications §39-2.02C

Where does the roller start on a hot mix mat with a crown or slope?

• a.At the lower edge, moving toward the high side✓
• b.At the lane edge farthest from the traffic
• c.At the high side, moving toward the lower edge
• d.Along the centerline, in either direction

Rolling starts at the lower edge and progresses toward the highest part so that the mat is confined as it is compacted. Starting high would push the mix downhill and leave the edge unsupported.Caltrans 2024 Standard Specifications §39-2.01C(15)(b)

A density core is 94.2 percent of theoretical maximum density. How is the lot paid?

• a.Payment is withheld until another core is taken
• b.It is removed and replaced at the contractor's cost
• c.With a reduction of 0.0125 for each tenth of a percent
• d.In full; 91.0 to 97.0 percent carries no reduction✓

Results from 91.0 to 97.0 percent of theoretical maximum density earn full payment. Reductions begin outside that range, removal applies below 89.0 or above 99.0 percent, and no waiting period is specified.Caltrans 2024 Standard Specifications §39-2.01A(4)(i)(ii)

How must longitudinal joints be placed in the lower layers of a multi-layer hot mix pavement?

• a.Offset by 6 feet from the lane line in each layer
• b.Stacked directly on top of one another in every layer
• c.At the center of each lane in every layer
• d.Alternated at least 0.5 foot to each side✓

Longitudinal joint offsets in lower layers alternate at least 0.5 foot from each side of the lane line, so that joints do not stack and form a weak plane. Stacking joints directly on top of one another and centering them in each lane create a weak plane, and a 6-foot offset from the lane line is not the stated practice.Caltrans 2024 Standard Specifications §39-2.01C(4)(a)

When may new hot mix pavement be opened to traffic?

• a.When it no longer smells strongly of asphalt
• b.After one hour of rolling is complete
• c.When the surface temperature is below 160°F in the sun
• d.When the mid-depth temperature is below 160°F✓

New hot mix may not be opened to traffic until its mid-depth temperature is below 160°F; the surface cools first and is not the measure. One hour of rolling and the loss of the asphalt smell are not criteria.Caltrans 2024 Standard Specifications §39-2.01C(15)(a)

When are contraction joints sawed in concrete pavement?

• a.After the full 28 days of curing
• b.After the slab has already cracked on its own
• c.Before it cracks, once hard enough to saw cleanly✓
• d.Before placement, using a grooving tool on the subbase

Contraction joints are sawed before the slab cracks naturally, but not before the concrete is hard enough to cut cleanly. Waiting for cracks defeats the joint, a groove in the subbase does not make a joint in the slab, and 28 days is far too late.Caltrans 2024 Standard Specifications §40-1.03B(3)

What is the maximum cross slope of an accessible walking surface?

• a.1:48✓
• b.1:20
• c.1:12
• d.1:10

Walking surfaces on an accessible route have a cross slope not steeper than 1:48. The 1:20 figure is the running slope limit, 1:12 is the ramp slope, and 1:10 is the curb ramp flare.2025 CBC §11B-403.3

What is the maximum rise of a single ramp run on an accessible route?

• a.12 inches
• b.60 inches
• c.30 inches✓
• d.48 inches

The rise of any ramp run is 30 inches maximum, after which a landing and another run are required. Twelve inches is lower than the maximum rise allowed, and 48 inches is a ramp width and 60 inches a landing size, so neither measures the rise of a run.2025 CBC §11B-405.6

What is the minimum width of an access aisle serving California car and van parking spaces?

• a.36 inches
• b.48 inches
• c.60 inches✓
• d.96 inches

Access aisles are 60 inches wide minimum. Thirty-six inches is a walkway pinch point, 48 inches is a walk or ramp width, and 96 inches is the aisle width that permits a narrower van space.2025 CBC §11B-502.3.1

What is the maximum slope of the flared sides of a curb ramp?

• a.1:10✓
• b.1:48
• c.1:12
• d.1:20

Curb ramp flares are not steeper than 1:10. The ramp run is 1:12, the counter slope is 1:20, and 1:48 is the maximum cross slope.2025 CBC §11B-406.2.2

What surface does a detectable warning at a curb ramp consist of?

• a.Parallel grooves cut across the ramp
• b.Yellow truncated domes✓
• c.A smooth steel plate
• d.A broom-finished concrete strip

Detectable warnings consist of a surface of truncated domes, and in California they are yellow. A broom finish, a smooth plate and grooves do not provide the specified tactile and visual warning.2025 CBC §11B-705.1

A lot has 60 parking spaces. How many accessible spaces does the California table require?

• a.2
• b.3✓
• c.4
• d.1

A lot of 51 to 75 spaces needs 3 accessible spaces. One is the 1-to-25 row, 2 is the 26-to-50 row, and 4 is the 76-to-100 row.2025 CBC Table 11B-208.2

A new walk meets an existing slab with a 3/8-inch vertical lip. What must be done?

• a.Fill the joint with loose sand and tamp it
• b.Bevel it at 1:2 or flatter, or make it flush✓
• c.Paint the edge yellow to warn pedestrians
• d.Leave it as it is; it is under 1/2 inch high

Changes in level up to 1/4 inch may be vertical, and from 1/4 to 1/2 inch must be beveled no steeper than 1:2. A 3/8-inch vertical lip violates the rule, and sand or paint does not fix the trip hazard.2025 CBC §11B-303.2 and 303.3

What is the temperature requirement for placing slurry seal or micro-surfacing?

• a.Pavement below 40°F and rising
• b.Pavement and air at least 50°F and rising✓
• c.Air at least 60°F and falling
• d.Pavement at least 80°F and falling slowly

Slurry seals and micro-surfacings require both pavement and air temperatures of at least 50°F and rising, with an expected high of at least 65°F in the next 24 hours. The 80°F surface is a chip seal condition, a falling temperature is the wrong direction, and cold pavement stops the emulsion from breaking.Caltrans 2024 Standard Specifications §37-3.01C(5)(b)

Under what weather conditions may asphaltic emulsion be applied for a chip seal?

• a.Air above 120°F, with a surface above 140°F
• b.Air at least 50°F, with the pavement surface dry
• c.Air 65 to 110°F and surface at least 80°F✓
• d.Air 40 to 50°F with a damp pavement surface

Emulsion for the chip seals described is applied when ambient air is 65 to 110°F and the pavement surface is at least 80°F, and not if air is forecast to fall below 39°F within 24 hours. Air above 120°F is outside the window, 50°F air with a dry surface falls short of both minimums, and 40 to 50°F air with a damp surface is far too cold.Caltrans 2024 Standard Specifications §37-2.02C

What should construction staff do with the subgrade soil beneath a permeable pavement?

• a.Seal it with a clay layer
• b.Not compact it✓
• c.Compact it to 100 percent of maximum density
• d.Compact it when dry

The EPA fact sheet says construction staff should not compact the subgrade soil, because the subgrade's infiltration capacity determines how much water can exfiltrate. Heavy compaction, sealing and conditional compaction reduce infiltration.U.S. EPA, Stormwater BMP: Permeable Pavements

Which finishing practice should be avoided when placing pervious concrete?

• a.Curing the concrete after finishing
• b.Floating and troweling the surface✓
• c.Consolidating with a non-vibratory steel roller
• d.Screeding the concrete to height

Floating and troweling can close the surface pores of pervious concrete and are avoided. Screeding to height, consolidating with a non-vibratory steel roller and curing are all used.U.S. EPA, Stormwater BMP: Permeable Pavements

At what interval are contraction joints spaced in a concrete curb under the State specification?

• a.20-foot intervals✓
• b.100-foot intervals
• c.60-foot intervals
• d.5-foot intervals

Curb contraction joints are spaced at 20-foot intervals. Sixty feet is the expansion joint interval for sidewalks with no adjacent curb, 5 feet is far closer than the curb spacing, and 100 feet is far wider.Caltrans 2024 Standard Specifications §73-2.03A

A colored concrete patio of 800 square feet is finished with dry-shake hardener at the minimum rate. How much hardener is used?

• a.60 pounds
• b.480 pounds✓
• c.48 pounds
• d.4,800 pounds

The minimum is 60 pounds per 100 square feet, so 8 × 60 = 480 pounds, applied in two applications. Sixty pounds is one unit, 4,800 and 48 shift the decimal.Caltrans 2024 Standard Specifications §73-4.03

How deep is the saw cut required before a portion of an asphalt concrete facility is removed?

• a.1/2 inch
• b.6 inches
• c.2 inches✓
• d.12 inches

A 2-inch-deep saw cut to a true line along the limits of the removal area is made before removal. Half an inch is too shallow to give a clean edge, while 6 and 12 inches cut deeper than the 2-inch depth stated.Caltrans 2024 Standard Specifications §39-3.01C

One panel of a concrete curb ramp is cracked. What does the State specification require for the repair?

• a.Replace the whole panel between joints✓
• b.Overlay the whole ramp with a thin asphalt layer
• c.Patch the crack with a cement mortar and seal it
• d.Patch the cracked corner of the panel

Repair of any part of a curb, sidewalk, curb ramp, driveway or gutter depression means removing and replacing the entire section between contraction or expansion joints. Patching, overlaying and corner repair leave a weak or non-compliant panel.Caltrans 2024 Standard Specifications §73-10.03

Which practice is prohibited when cold planing asphalt concrete pavement?

• a.Using a heater to soften the pavement✓
• b.Controlling dust from the planing operation
• c.Removing planed material behind the machine
• d.Using automatic grade and slope controls

The specification says not to use a heating device to soften the pavement. Dust control, automatic grade and slope controls and prompt removal of planed material are required.Caltrans 2024 Standard Specifications §39-3.04C(1)

Which statement describes replacement of asphalt concrete surfacing?

• a.A material transfer vehicle on every patch, with cores
• b.Type A hot mix, method compaction, no transfer vehicle✓
• c.Rubberized hot mix in a single thick lift
• d.Compaction accepted by density cores, without rollers

Replacement HMA is Type A, placed with method compaction, and a material transfer vehicle is not used for replacing asphalt concrete surfacing. Cores are not the acceptance method for method compaction, and the specification does not require rubberized mix.Caltrans 2024 Standard Specifications §39-3.02

Base and surfacing are to be removed. To what depth is the removal made?

• a.At least 6 inches below the grade of the existing surfacing✓
• b.2 inches below the existing surfacing, to save backfill
• c.To the bottom of the asphalt layer
• d.3 feet below the pavement surface everywhere

Removal goes to a depth of at least 6 inches below the grade of the existing surfacing, and holes are backfilled with embankment material. Stopping at the bottom of the asphalt layer leaves the base in place, 2 inches below the existing surfacing is shallower than the 6-inch minimum, and 3 feet everywhere is far deeper than the stated depth.Caltrans 2024 Standard Specifications §39-3.05C

After a chip seal has been swept, within how many days must permanent traffic stripes and pavement markings be placed?

• a.6 months
• b.24 hours
• c.10 days✓
• d.60 days

Permanent stripes and markings are placed within 10 days wherever maintenance sweeping is complete, or the owner withholds 50 percent of the value of the unstriped chip seal work. Six months and 60 days are far longer than the allowed time, and 24 hours is shorter than the 10 days the specification allows.Caltrans 2024 Standard Specifications §37-2.01C(1)

By when must soil tracked onto a public street from the job site be removed?

• a.Within 6 hours, and never allowed into a storm drain✓
• b.By the end of the work week, then swept
• c.Within 72 hours, and if the weather is dry
• d.After the project is finished, then swept

Material tracked onto the surfacing must be removed within 6 hours and may not enter storm drains, open drainage facilities or watercourses. The longer periods let sediment wash into drains.Caltrans 2024 Standard Specifications §13-7.01C

A chip seal will affect parking on a residential street. How far ahead must residents be notified and how are signs spaced?

• a.At least 7 days ahead, with signs at 500-foot intervals
• b.The morning of the work, with signs at each end
• c.A printed notice the day after the work, with one sign
• d.24 hours ahead, with signs at 100-foot intervals✓

The contractor posts No Parking - Tow Away signs at 100-foot intervals stating the dates and hours and notifies residents, businesses and local agencies at least 24 hours before starting. Seven days with signs at 500-foot intervals asks for more notice and wider spacing than stated, notice on the morning of the work is too late and signs at the ends leave gaps, and notice after the work gives residents no chance to move their cars.Caltrans 2024 Standard Specifications §37-1.03A

Before a chip seal is applied, what is done to manholes, valve covers and grates in the area?

• a.Paved over, then located later by trial digging
• b.Removed and the openings capped permanently
• c.Left exposed to receive the seal like the roadway
• d.Covered with plastic or paper and referenced✓

Exposed facilities are covered with plastic or oil-resistant construction paper secured by tape or adhesive and referenced with control points so they can be found afterward. Paving over them blindly or leaving them exposed makes them hard to find or coats them.Caltrans 2024 Standard Specifications §37-2.01C(3)

Work will close a sidewalk and the plans do not show a temporary pedestrian access route. What does the State specification require?

• a.A single cone and a sign placed at each end
• b.A route if the closure will last over a month
• c.A flagger who walks pedestrians through the traffic lane
• d.A work plan for a temporary route sealed by a civil engineer✓

If work closes a pedestrian route and no temporary route is shown, a work plan for one is submitted, sealed and signed by an engineer registered as a civil engineer in the State. A cone and sign do not provide a route, there is no one-month threshold, and walking pedestrians through the traffic lane is not an access route.Caltrans 2024 Standard Specifications §12-4.04A(3)

Which document must every employer adopt in writing under the Cal/OSHA construction safety orders?

• a.A schedule of equipment rental prices by hour
• b.A forecast of the employer's yearly profit margin
• c.A summary of its competitors' safety records
• d.A written Code of Safe Practices for its work✓

Every employer must adopt a written Code of Safe Practices related to its operations and post it at each job site office or give it to each supervisor. An equipment rental schedule, a profit forecast and a summary of competitors' safety records have nothing to do with the safety order.8 CCR §1509(b), (c)

Which vehicles must have an automatic warning device that operates while backing?

• a.Vehicles that operate at night or in poor light on site
• b.Vehicles on public streets or highways, not job sites
• c.Haulage vehicles of 2-1/2 cubic yards or more✓
• d.Haulage vehicles that carry more than 20 cubic yards

The automatic warning is required on haulage vehicles of 2-1/2 cubic yards or more that haul dirt, rock, concrete or construction material, with a sound normally audible from 200 feet. Backing alarms are not limited to night work or to public streets, and a 20-cubic-yard limit is far above the 2-1/2 cubic-yard threshold.8 CCR §1592(a)

A grader is parked on an incline at the end of the shift. What is required?

• a.Brake set and the wheels chocked on the incline✓
• b.Key removed and the cab door locked overnight
• c.Transmission left in gear for the night
• d.Blade raised clear of the ground and the engine off

Parked equipment has its parking brake set, and equipment parked on an incline also has its wheels chocked or is otherwise prevented from moving by effective mechanical means. Gear, blade position and key removal do not hold the machine.8 CCR §1593(h)

At what sound level does the Cal/OSHA noise table permit an 8-hour daily exposure?

• a.70 dBA
• b.105 dBA
• c.90 dBA✓
• d.120 dBA

Table N-1 permits 8 hours at 90 dBA, and the permitted duration drops as the level rises (1 hour at 105 dBA). Seventy dBA is well below the limit, and 120 dBA would be permitted for only seconds.8 CCR §5096, Table N-1

How much drinking water must be provided per employee for a shift under California's heat standard when water is not plumbed?

• a.One gallon for the whole shift per employee
• b.One pint for the whole shift per employee
• c.Water on request, in the afternoon
• d.One quart per hour for the entire shift✓

The employer provides potable water in sufficient quantity at the beginning of the shift to supply one quart per employee per hour, or has effective replenishment procedures. A pint or a gallon for the shift does not match the hourly rate, and water is not limited to afternoon requests.8 CCR §3395(c)

Before maintenance is done under a raised dump body, what must be in place?

• a.A spare tire placed under the raised bed
• b.A spotter standing nearby to give warning
• c.The engine left running to hold up the hydraulics
• d.A permanently attached, locked-in-place positive support✓

Dump bodies must have a positive means of support, permanently attached and capable of being locked, and the locking device must be used whenever the body is raised for any work. Tires, hydraulic pressure and spotters cannot prevent a sudden drop.8 CCR §1595(b)

Which rule applies when fueling equipment?

• a.An extinguisher kept in the shop, away from the fueling area
• b.No refueling while running; 25-foot no-smoking sign✓
• c.Refuel while the engine runs, to save restart time
• d.Smoking allowed 5 feet from the fueling nozzle

Fuel tanks are not refilled while the engine is running, the fueling area carries a "NO SMOKING WITHIN 25 FEET" sign, and a fire extinguisher rated 6:BC or larger is accessible. An extinguisher in the shop is not accessible to the fueling area, refueling with the engine running to save restart time is prohibited, and smoking at 5 feet breaks the 25-foot rule.8 CCR §1594

Which scraper and bulldozer protection does Cal/OSHA require on covered earthmoving equipment above 20 brake horsepower?

• a.Neither, if the machine works on level ground
• b.ROPS and seat belts, with belt use required by the employer✓
• c.Seat belts, if the operator asks for them
• d.ROPS, when the machine works on public roads

ROPS and seat belts are required on scrapers, tractors, front-end loaders, bulldozers, motor graders and water wagon prime movers above 20 brake horsepower, and the employer requires belt use. Optional belts, public-road-only ROPS and a level-ground exception do not appear.8 CCR §1596(a), §1597(h)

A site disturbs 2 acres of soil. What does the State stormwater permit require?

• a.A license endorsement issued by CSLB
• b.Permit coverage and a SWPPP written by a QSD✓
• c.Coverage if the site will be paved afterward
• d.No coverage; sites over 10 acres are covered

Sites that disturb one or more acres need coverage under the construction general permit, and the SWPPP is developed by a Qualified SWPPP Developer. The 10-acre threshold is not in the order, paving afterward does not decide coverage, and CSLB does not issue the permit.SWRCB Order WQ 2022-0057-DWQ

Under the construction general permit, which person develops the SWPPP, and which implements it on site?

• a.The owner's accountant develops it for the permit
• b.The equipment operator develops it on site
• c.A QSP develops it; a QSD implements and inspects it
• d.A QSD develops it; a QSP implements and inspects it✓

The SWPPP and amendments are developed by a Qualified SWPPP Developer, while a Qualified SWPPP Practitioner implements it and performs the required inspections. The other assignments are not in the order.SWRCB Order WQ 2022-0057-DWQ §V

How far from a storm drain inlet, open drainage facility or watercourse must a temporary concrete washout be placed?

• a.No closer than 5 feet
• b.No closer than 15 feet
• c.No closer than 50 feet✓
• d.Immediately beside it

The State specification places washouts no closer than 50 feet from storm drain inlets, open drainage facilities, ESAs and watercourses. Five and 15 feet are too close, and beside the inlet defeats the purpose.Caltrans 2024 Standard Specifications §13-9.03

How full may a concrete washout be filled?

• a.It may overflow slightly before disposal
• b.No higher than 75 percent of its capacity✓
• c.No higher than 50 percent of its capacity
• d.No higher than 100 percent of its capacity

The washout is not filled higher than 75 percent of capacity so that it cannot overflow in rain or when moved. One hundred percent and overflowing violate the rule, and 50 percent is stricter than stated.Caltrans 2024 Standard Specifications §13-9.03

How does the State specification define a storm event?

• a.A forecast of 2 inches or more within 24 hours
• b.A 50 percent chance of 0.5 inch or more within 24 hours✓
• c.A National Weather Service hurricane warning
• d.Measurable rain during the work shift

A storm event is any weather pattern forecast to have a 50 percent or greater probability of precipitation and a quantitative precipitation forecast of 0.5 inch or more within a 24-hour period. Any rain, 2 inches and hurricanes are not the definition.Caltrans 2024 Standard Specifications §13-1.01B

Where must flammable or hazardous wastes generated on the job site be placed?

• a.Stacked on the ground near the work area
• b.In covered containers apart from other debris✓
• c.In an open trench until the end of the job
• d.In the regular debris dumpster with the trash

Flammable or hazardous wastes go in covered containers separate from normal debris. The regular dumpster, the ground and a trench would mix or release hazardous material.8 CCR §1513(e)

What does Cal/OSHA require about dust on haul roads and in dusty operations?

• a.Control dust for visibility; respirators for operators✓
• b.Dust control only after neighbors complain
• c.A ban on all earthmoving in dry weather months
• d.Dust masks for pedestrians near the work, not for operators

Action must be taken to prevent dust from seriously reducing visibility, and in dusty operations equipment operators use adequate respiratory protection. Controlling dust only after complaints waits for a problem the order tells the employer to prevent, no ban on dry-season earthmoving exists, and masks for pedestrians do not replace protection for the operators who work in the dust.8 CCR §1590(b)

A closure is on a 25 mph street with a 12-foot lane shift. What is the minimum merging taper length using the manual's formula?

• a.12 feet
• b.300 feet
• c.63 feet
• d.125 feet✓

At 40 mph or less L = WS² ÷ 60 = 12 × 625 ÷ 60 = 125 feet. The 300-foot figure uses L = WS (the 45 mph and above formula), 63 feet is the shifting taper, and 12 feet is just the offset.California MUTCD 2026 Edition, Table 6B-4

Which are the four areas of a temporary traffic control zone?

• a.Entry, middle, exit and staging areas of the zone
• b.Advance warning, transition, activity, termination✓
• c.Work, rest, storage and office areas of the zone
• d.Flagger, cone, sign and barrier areas of the zone

The manual divides a TTC zone into the advance warning area, the transition area, the activity area and the termination area. The other lists name equipment or functions that are not the zone parts.California MUTCD 2026 Edition §6B.03

Flagger garments worn in the dark must have retroreflective material visible at what minimum distance?

• a.1,000 feet✓
• b.300 feet
• c.5,000 feet
• d.100 feet

The retroreflective material must be visible at a minimum distance of 1,000 feet, and the flagger's station must be illuminated. Three hundred feet and 100 feet are too short for a driver to react, and 5,000 feet is far beyond the stated distance.8 CCR §1599(e)

What is the minimum height of a traffic cone under the State specification?

• a.28 inches✓
• b.36 inches
• c.12 inches
• d.18 inches

The overall height of a traffic cone must be at least 28 inches, with a retroreflective sleeve during darkness. Twelve and 18 inches are too short to be visible, and 36 inches is the nominal height of larger cones but not the stated minimum.Caltrans 2024 Standard Specifications §12-3.02B

A truck is parked in the buffer space of a work zone. What does the manual say about the buffer space?

• a.Temporary aggregate stockpiles are allowed there
• b.Idle equipment is best parked there between uses
• c.No work or storage of equipment, vehicles or materials there✓
• d.Traffic cones must fill it

The buffer space separates road users from the work space and provides recovery room for an errant vehicle, so neither work nor storage of equipment, vehicles or materials should occur in it. Stockpiling and parking idle equipment are the very uses it forbids, and the buffer space is kept open as recovery room rather than filled with cones.California MUTCD 2026 Edition §6B.06

A merging taper at a lane closure is calculated as 240 feet long. What is the minimum length of a shifting taper at the same location?

• a.120 feet✓
• b.50 feet
• c.240 feet
• d.80 feet

A shifting taper is at least 0.5 L, so 0.5 × 240 = 120 feet. The 240-foot figure is the merging taper, 80 feet is about one-third of L (the shoulder taper), and 50 feet is the downstream taper minimum.California MUTCD 2026 Edition, Table 6B-3