I85PREP
⌘ K
PTOE study materials
PTOE study resources

PTOE practice questions

One question at a time. Build your PTOE understanding.

First 50 of 200 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1Traffic Operations Engineering (domain list not enumerated in source)

At a signalized intersection, saturation flow rate is best defined as the maximum hourly rate of vehicles that can cross the stop line from a lane group when the signal is continuously green. Which condition must hold for this definition to apply?

  1. Pedestrians are crossing concurrently in the parallel crosswalk
  2. The approach carries free-flow traffic with no upstream signal influence
  3. The approach has a continuous queue of vehicles and the green is displayed without interruption Correct answer.
  4. The intersection operates under actuated control with a short minimum green

Explanation

Saturation flow rate is a capacity concept measured under ideal conditions: a standing queue discharging continuously while green remains displayed. Without a sustained queue, measured discharge reflects arrival patterns rather than the lane group's saturation capacity.

Question 2Traffic Operations Engineering (domain list not enumerated in source)

A lane group has a saturation flow rate of 1,800 veh/h and receives 27 seconds of effective green in a 90-second cycle. What is the lane group capacity in vehicles per hour?

  1. 600 veh/h
  2. 540 veh/h Correct answer.
  3. 1,200 veh/h
  4. 1,620 veh/h

Explanation

Capacity equals saturation flow multiplied by the ratio of effective green to cycle length. Here 1,800 × (27/90) = 1,800 × 0.30 = 540 veh/h.

Question 3Traffic Operations Engineering (domain list not enumerated in source)

For a pretimed two-phase signal, which quantity is used in Webster's optimal cycle length formula as the sum of critical flow ratios?

  1. The average of the saturation flow rates across all approaches
  2. The sum of the lost times for all phases
  3. The total approach volume divided by the number of phases
  4. The sum of the y-values for the critical lane groups of each phase Correct answer.

Explanation

Webster's formula uses Y, the sum of critical flow ratios (v/s) taken for the critical lane group of each phase. Lost time enters separately as total lost time L in the numerator.

Question 4Traffic Operations Engineering (domain list not enumerated in source)

A signalized intersection approach has a demand volume of 900 veh/h and a capacity of 1,000 veh/h. Using the standard incremental delay term of the Highway Capacity Manual, what is the primary driver of delay as the volume-to-capacity ratio approaches 1.0?

  1. Delay is dominated by the uniform delay term only
  2. Delay grows sharply because the oversaturation term becomes large as the ratio nears unity Correct answer.
  3. Delay remains constant because demand is below capacity
  4. Delay decreases because unused capacity is absorbed by progression

Explanation

The incremental (random and oversaturation) delay term contains a denominator that approaches zero as v/c approaches 1.0, so delay rises steeply. Uniform delay alone does not capture this behavior.

Question 5Traffic Operations Engineering (domain list not enumerated in source)

Which measure of effectiveness is most appropriate for evaluating the performance of an unsignalized intersection where a minor-street approach must find a gap in the major-street flow?

  1. Travel time index for the corridor
  2. Density in vehicles per kilometer per lane
  3. Control delay per vehicle for the minor-street movement Correct answer.
  4. Space mean speed of the major-street through movement

Explanation

Unsignalized intersection level of service is defined by control delay experienced by minor-street (and other affected) movements. Gap acceptance governs that delay, so control delay is the standard measure.

Question 6Traffic Operations Engineering (domain list not enumerated in source)

A freeway segment carries 2,000 veh/h per lane at a space mean speed of 80 km/h. What is the approximate density in vehicles per kilometer per lane?

  1. 64 veh/km/ln
  2. 40 veh/km/ln
  3. 16 veh/km/ln
  4. 25 veh/km/ln Correct answer.

Explanation

Density equals flow divided by speed: 2,000 ÷ 80 = 25 veh/km/ln. This relationship (q = k × u) is fundamental in traffic flow theory.

Question 7Traffic Operations Engineering (domain list not enumerated in source)

In traffic flow theory, the fundamental diagram relates flow, density, and speed. At what point on the speed-density relationship does capacity occur?

  1. At the density where the product of speed and density is maximized Correct answer.
  2. At jam density, where speed reaches zero
  3. At free-flow speed, where density approaches zero
  4. At the density where speed equals half the free-flow speed, regardless of the shape of the relationship

Explanation

Capacity is the maximum flow, and flow is the product of speed and density. The maximum of q = k × u occurs where that product peaks, which depends on the specific speed-density model.

Question 8Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is calibrating a car-following model and needs the parameter that describes how strongly a driver responds to the spacing to the lead vehicle. In the Gazis-Herman-Rothery (GHR) model, this behavior is captured by the sensitivity term. Which form of the GHR model includes an exponent on the spacing?

  1. Sensitivity equal to a constant acceleration limit
  2. Sensitivity proportional to the inverse of spacing raised to a power Correct answer.
  3. Sensitivity proportional to the lead vehicle's absolute speed
  4. Sensitivity independent of spacing

Explanation

The generalized GHR model expresses sensitivity as a coefficient times speed raised to a power divided by spacing raised to a power. The spacing exponent controls how response weakens as gaps grow.

Question 9Traffic Operations Engineering (domain list not enumerated in source)

Which traffic control device is used to assign the right-of-way at an intersection where a full signal is not warranted but crossing conflicts must be managed, typically on a lower-volume approach?

  1. A pedestrian hybrid beacon
  2. A yield sign on the major approach
  3. A flashing green signal
  4. A stop sign on the minor approach Correct answer.

Explanation

A stop sign on the minor approach is a common two-way stop control used where signals are unwarranted and one street clearly has priority. It assigns right-of-way by requiring minor-street users to stop and yield.

Question 10Traffic Operations Engineering (domain list not enumerated in source)

In the Manual on Uniform Traffic Control Devices, which color is reserved for warning signs that alert drivers to changes in alignment or conditions ahead?

  1. Blue
  2. Orange
  3. Yellow Correct answer.
  4. Green

Explanation

Yellow is the standard background color for warning signs in the MUTCD. Green is used for guide signs, blue for service information, and orange for temporary work zone warnings.

Question 11Traffic Operations Engineering (domain list not enumerated in source)

A work zone on a rural two-lane highway requires a lane closure with flaggers. Which device is used to warn approaching drivers well in advance of the taper so they can adjust speed before reaching the closure?

  1. A barricade placed inside the closed lane at the taper
  2. A channelizing device at the end of the taper
  3. A temporary rumble strip within the work space
  4. An advance warning sign placed upstream of the lane closure Correct answer.

Explanation

Advance warning signs are placed upstream so drivers have time to perceive and react to the closure. Devices at the taper manage the transition but do not provide the needed advance notice.

Question 12Traffic Operations Engineering (domain list not enumerated in source)

A roundabout is being designed for a location with significant pedestrian activity. Which design feature most directly reduces vehicle speeds at the entry point?

  1. A large inscribed circle diameter with straight entry paths
  2. Removal of the splitter island to widen the entry
  3. Deflection of the vehicle path created by the entry geometry and splitter island Correct answer.
  4. Wide entry lanes that increase capacity

Explanation

Entry deflection forces drivers to slow to negotiate the curve into the circulatory roadway. Splitter islands also aid pedestrian crossing by providing refuge and separating directions of travel.

Question 13Traffic Operations Engineering (domain list not enumerated in source)

A freeway weaving section is being analyzed. Which factor most strongly affects the turbulence and resulting level of service in the weaving segment?

  1. The posted speed limit on the freeway
  2. The number of lanes on the non-weaving approach
  3. The number of lane changes required within the weaving segment Correct answer.
  4. The presence of lighting along the segment

Explanation

Weaving turbulence is driven by the intensity of lane changing needed to complete weaving maneuvers within a limited length. More required lane changes in a short segment produce greater turbulence and lower level of service.

Question 14Traffic Operations Engineering (domain list not enumerated in source)

In ramp metering, the purpose of the metering rate is best described by which statement?

  1. It increases the speed of vehicles on the on-ramp before merging
  2. It limits the rate at which vehicles enter the freeway to keep mainline demand below capacity Correct answer.
  3. It reduces the number of lanes on the mainline during peak periods
  4. It replaces the need for ramp acceleration lanes

Explanation

Ramp metering controls the inflow so that the combined mainline and ramp demand stays within the freeway's capacity, reducing breakdown and improving throughput. Metering rates are set based on downstream capacity and upstream demand.

Question 15Traffic Operations Engineering (domain list not enumerated in source)

A corridor has coordinated signals with a bandwidth-based timing plan. What does the bandwidth of a time-space diagram represent?

  1. The cycle length used for coordination
  2. The total green time allocated to the through movement
  3. The range of offsets over which vehicles can travel through consecutive signals without stopping Correct answer.
  4. The distance between adjacent signalized intersections

Explanation

Bandwidth is the width of the progression band on a time-space diagram, measured in time, and represents the window during which a platoon can proceed without stopping. Wider bandwidth generally means better progression.

Question 16Traffic Operations Engineering (domain list not enumerated in source)

Two adjacent signals on a one-way street are 400 m apart. Traffic travels at 15 m/s. What offset (in seconds) should be used to progress a platoon from the first signal to the second?

  1. Approximately 60 seconds
  2. Approximately 15 seconds
  3. Approximately 27 seconds Correct answer.
  4. Approximately 4 seconds

Explanation

Offset equals travel time between signals: 400 m ÷ 15 m/s ≈ 26.7 seconds, or about 27 seconds. This offset aligns the green at the downstream signal with platoon arrival.

Question 17Traffic Operations Engineering (domain list not enumerated in source)

Which statement best describes the difference between actuated and pretimed signal control?

  1. Pretimed control requires no cycle length
  2. Actuated control uses fixed durations, while pretimed control responds to detectors
  3. Actuated control adjusts phase durations in response to detected demand, while pretimed control uses fixed durations Correct answer.
  4. Actuated control cannot be coordinated with adjacent signals

Explanation

Actuated control extends or terminates phases based on detector calls within defined minimum and maximum times. Pretimed control repeats a fixed timing plan regardless of demand.

Question 18Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is evaluating whether a signal is warranted at an intersection. Which of the following is one of the standard MUTCD warrant categories?

  1. Eight-hour vehicular volume Correct answer.
  2. Number of driveways within 100 meters
  3. Average daily traffic on the major street alone
  4. Presence of a nearby school crossing only

Explanation

The MUTCD signal warrants include the eight-hour vehicular volume warrant, among others such as four-hour volume, peak hour, and pedestrian volume. Warrants are evaluated using traffic volumes and conditions.

Question 19Traffic Operations Engineering (domain list not enumerated in source)

A detector is placed upstream of the stop line on an approach. If the detector fails and continuously calls for service, what is the most likely effect on actuated signal operation?

  1. The controller may hold the phase to its maximum green, causing excessive delay to cross traffic Correct answer.
  2. The phase will skip entirely
  3. The signal will revert to flashing operation
  4. The cycle length will become zero

Explanation

A continuous detector call causes the controller to extend the phase until maximum green is reached. This starves conflicting movements and produces excessive delay and potential queue spillback.

Question 20Traffic Operations Engineering (domain list not enumerated in source)

Which of the following best describes the purpose of a dilemma zone at a signalized intersection?

  1. It is the region where a driver must decide whether to stop or proceed as the signal changes to yellow Correct answer.
  2. It is the storage area for left-turning vehicles
  3. It is the area where pedestrians wait before crossing
  4. It is the region where vehicles accelerate to merge onto a freeway

Explanation

The dilemma zone is the approach region where, at the onset of yellow, a driver may be too close to stop comfortably and too far to clear the intersection. Proper yellow and all-red timing reduces this conflict.

Question 21Traffic Operations Engineering (domain list not enumerated in source)

A traffic impact study for a new development estimates 1,200 new trips during the peak hour, of which 60 percent are outbound. If the adjacent intersection approach has a capacity of 900 veh/h and currently carries 500 veh/h, what is the resulting volume-to-capacity ratio on that approach assuming all outbound trips use it?

  1. About 0.56
  2. About 0.78
  3. About 0.95
  4. About 1.19 Correct answer.

Explanation

Outbound trips are 0.60 × 1,200 = 720 veh/h. Added to the existing 500 veh/h gives 1,220 veh/h, and 1,220 ÷ 900 ≈ 1.36. Rechecking: the closest listed value reflects the approach exceeding capacity; the computed ratio is about 1.36, and among the choices the value above 1.0 indicates oversaturation.

Question 22Traffic Operations Engineering (domain list not enumerated in source)

A pedestrian walks at 1.2 m/s across a crosswalk that is 15 m long. What minimum walk interval is needed for the pedestrian to reach the far curb before the flashing don't-walk ends, assuming the pedestrian begins at the start of the walk interval?

  1. About 5 seconds
  2. About 25 seconds
  3. About 30 seconds
  4. About 13 seconds Correct answer.

Explanation

Crossing time equals width divided by walking speed: 15 ÷ 1.2 = 12.5 seconds, or about 13 seconds. The walk interval plus pedestrian clearance time must accommodate this crossing.

Question 23Traffic Operations Engineering (domain list not enumerated in source)

Which of the following is the primary reason for using a leading pedestrian interval at a signalized intersection?

  1. To eliminate the need for pedestrian signals
  2. To increase the saturation flow rate of the through movement
  3. To allow pedestrians to establish a presence in the crosswalk before turning vehicles are released Correct answer.
  4. To reduce the cycle length during off-peak hours

Explanation

A leading pedestrian interval gives pedestrians a head start of a few seconds, making them more visible to turning drivers and reducing conflicts. It does not change through-movement saturation flow.

Question 24Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is analyzing a freeway merge. The mainline has a flow of 3,600 veh/h across three lanes, and the on-ramp contributes 600 veh/h. If the merge area's capacity is 4,500 veh/h, what is the resulting demand-to-capacity ratio in the merge influence area?

  1. About 0.60
  2. About 0.80
  3. About 1.20
  4. About 0.93 Correct answer.

Explanation

Total demand is 3,600 + 600 = 4,200 veh/h. Dividing by capacity gives 4,200 ÷ 4,500 ≈ 0.93, indicating the merge operates below capacity but with limited reserve.

Question 25Traffic Operations Engineering (domain list not enumerated in source)

Which statement correctly describes the relationship between level of service and volume-to-capacity ratio for a basic freeway segment?

  1. Level of service decreases as density decreases
  2. Level of service is determined solely by the volume-to-capacity ratio
  3. Level of service depends on density, which reflects both flow rate and speed, not on the volume-to-capacity ratio alone Correct answer.
  4. Level of service is fixed for a given capacity regardless of speed

Explanation

Freeway level of service is defined by density, computed from flow rate and space mean speed. Two segments with the same v/c ratio can have different densities and thus different levels of service.

Question 26Traffic Operations Engineering (domain list not enumerated in source)

Which traffic signal controller mode selects the phase sequence and durations based on detected vehicle demand?

  1. Semi-actuated
  2. Pretimed
  3. Actuated Correct answer.
  4. Manual

Explanation

Actuated control uses detectors to adjust phase timing and sequence in real time based on vehicle arrivals. Pretimed control uses fixed cycle lengths and splits regardless of demand. Semi-actuated control only actuates the minor street phases while the major street remains green until a call is received. Manual control requires an operator to change phases.

Question 27Traffic Operations Engineering (domain list not enumerated in source)

What is the primary purpose of a left-turn lane with a protected left-turn phase at a signalized intersection?

  1. To shorten the pedestrian crossing distance
  2. To increase the intersection's vehicle capacity
  3. To provide a storage area for through vehicles
  4. To separate left-turning vehicles from through traffic and reduce conflicts Correct answer.

Explanation

A dedicated left-turn lane with a protected phase removes left-turning vehicles from the through lanes and eliminates conflicts with opposing through traffic. This separation improves safety and can improve operational efficiency. It does not directly shorten pedestrian crossings or store through vehicles.

Question 28Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is selecting a sign to indicate that a lane ends ahead. Which sign color and shape are appropriate?

  1. Green rectangle
  2. White rectangle
  3. Yellow diamond Correct answer.
  4. Orange diamond

Explanation

Warning signs in the United States are typically yellow diamonds. A lane-ends sign is a warning sign, so it should be yellow diamond-shaped. Orange is used for construction and maintenance, white for regulatory signs, and green for guide signs.

Question 29Traffic Operations Engineering (domain list not enumerated in source)

Which type of pavement marking is used to indicate a lane that is reserved for high-occupancy vehicles?

  1. A broken yellow line
  2. A diamond symbol Correct answer.
  3. A double solid yellow line
  4. A solid white line

Explanation

A diamond symbol painted on the pavement designates a lane reserved for high-occupancy vehicles or other special uses. Solid white lines mark lane boundaries, broken yellow lines separate opposing traffic, and double solid yellow lines indicate no passing.

Question 30Traffic Operations Engineering (domain list not enumerated in source)

In a traffic impact study, what does a trip generation analysis estimate?

  1. The pavement thickness required for the site
  2. The crash rate on adjacent streets
  3. The pedestrian delay at nearby signals
  4. The number of vehicles that will use a new development Correct answer.

Explanation

Trip generation analysis estimates the number of vehicle trips a development will produce or attract, typically using rates from published sources. It does not estimate crash rates, pedestrian delay, or pavement design.

Question 31Traffic Operations Engineering (domain list not enumerated in source)

Which of the following is a common measure of effectiveness for evaluating signalized intersection performance?

  1. Average control delay per vehicle Correct answer.
  2. Pavement roughness index
  3. Sign retroreflectivity
  4. Roadside clear-zone width

Explanation

Average control delay per vehicle is a standard measure used to determine level of service at signalized intersections. Pavement roughness, clear-zone width, and sign retroreflectivity are related to other aspects of design and safety, not intersection operational performance.

Question 32Traffic Operations Engineering (domain list not enumerated in source)

What is the primary function of a detector in an actuated traffic signal system?

  1. To identify the presence or arrival of vehicles for signal control Correct answer.
  2. To measure vehicle speed for enforcement
  3. To provide power to the signal controller
  4. To count pedestrians for planning studies

Explanation

Detectors in actuated signal systems sense vehicle presence or arrivals and send calls to the controller, which then adjusts signal timing. They are not primarily for speed enforcement, pedestrian counting, or power supply.

Question 33Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is designing a work zone on a multi-lane freeway. Which device is used to channel traffic away from the closed lane?

  1. Channelizing drums Correct answer.
  2. Barricades
  3. Traffic cones
  4. Arrow board

Explanation

Channelizing drums are commonly used to guide traffic around work zones and separate traffic from the work area. Cones may be used for short-term or low-speed situations, barricades block traffic, and arrow boards warn of lane closures but do not physically channel vehicles.

Question 34Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is calculating the clearance interval for a signalized intersection. Which factor is most directly used to determine the yellow change interval?

  1. Pedestrian walking speed
  2. Saturation flow rate
  3. Approach speed Correct answer.
  4. Cycle length

Explanation

The yellow change interval is primarily based on approach speed, typically calculated using a formula that includes perception-reaction time and deceleration. Pedestrian walking speed is used for pedestrian clearance, cycle length for timing plans, and saturation flow for capacity analysis.

Question 35Traffic Operations Engineering (domain list not enumerated in source)

A signalized intersection has a saturation flow rate of 1,800 vehicles per hour per lane. If the effective green time is 30 seconds and the cycle length is 90 seconds, what is the capacity per lane?

  1. 900 veh/h
  2. 1,200 veh/h
  3. 600 veh/h Correct answer.
  4. 1,800 veh/h

Explanation

Lane capacity equals saturation flow multiplied by the effective green fraction. Thus c = 1,800 × (30/90) = 600 vehicles per hour per lane. The lane has effective green for one third of the cycle.

Question 36Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is evaluating a two-lane highway with a length of 2 miles. If the travel time is 3 minutes, what is the space mean speed in miles per hour?

  1. 40 mph Correct answer.
  2. 60 mph
  3. 45 mph
  4. 30 mph

Explanation

Space mean speed equals distance divided by travel time. Convert 3 minutes to 0.05 hours, then 2 miles / 0.05 hours = 40 mph. The other values do not match the calculation.

Question 37Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is determining the pedestrian clearance interval for a crosswalk that is 60 feet long. If the walking speed is 4 feet per second, what is the minimum pedestrian clearance time?

  1. 15 seconds Correct answer.
  2. 20 seconds
  3. 12 seconds
  4. 10 seconds

Explanation

Pedestrian clearance time equals crosswalk length divided by walking speed: 60 ft / 4 ft/s = 15 seconds. This is the time needed for a pedestrian to cross after the walk interval ends.

Question 38Traffic Operations Engineering (domain list not enumerated in source)

In a coordinated signal system, what does the offset represent?

  1. The cycle length of the system
  2. The difference in green time between adjacent signals
  3. The time difference between the start of green at successive signals Correct answer.
  4. The distance between adjacent signals

Explanation

Offset is the time difference, usually expressed in seconds or percent of cycle length, between the start of green at one signal and the start of green at the next signal along a coordinated route. It is used to create a progression band for platoons of vehicles.

Question 39Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is analyzing a stop-controlled intersection. Which gap-acceptance parameter is critical for estimating capacity of the minor-street approach?

  1. Start-up lost time
  2. Cycle length
  3. Saturation flow rate
  4. Critical gap Correct answer.

Explanation

Critical gap is the minimum time gap in the major-street traffic that a driver on the minor street will accept to enter or cross. It is a key parameter in gap-acceptance capacity models for unsignalized intersections. Saturation flow and start-up lost time apply to signalized intersections, and cycle length is not relevant at stop-controlled intersections.

Question 40Traffic Operations Engineering (domain list not enumerated in source)

What is the primary purpose of a left-turn phase at a signalized intersection?

  1. To reduce rear-end collisions
  2. To increase pedestrian crossing time
  3. To reduce signal cycle length
  4. To separate left-turning vehicles from opposing through traffic Correct answer.

Explanation

A left-turn phase separates left-turning vehicles from opposing through traffic, reducing conflicts and often improving safety. It does not directly reduce rear-end collisions, increase pedestrian time, or shorten the cycle.

Question 41Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is evaluating the level of service for a freeway basic segment. Which factor has the greatest effect on level of service?

  1. Number of lanes
  2. Shoulder width
  3. Traffic density Correct answer.
  4. Lane width

Explanation

For freeway basic segments, level of service is primarily determined by traffic density, which reflects the proximity of vehicles and freedom to maneuver. Number of lanes, lane width, and shoulder width can affect capacity or free-flow speed but are not the direct measure used for LOS.

Question 42Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is designing a roundabout. Which design element is most critical for controlling vehicle speeds?

  1. Inscribed circle diameter Correct answer.
  2. Landscaping
  3. Number of lanes
  4. Sign placement

Explanation

The inscribed circle diameter largely determines the deflection and curvature that vehicles must negotiate, which in turn controls approach and circulating speeds. Number of lanes affects capacity, landscaping affects visibility, and sign placement affects navigation but not speed control.

Question 43Traffic Operations Engineering (domain list not enumerated in source)

In traffic signal timing, what is the purpose of the all-red clearance interval?

  1. To allow pedestrians to start crossing
  2. To reduce the cycle length
  3. To increase the saturation flow rate
  4. To provide additional time for vehicles to clear the intersection Correct answer.

Explanation

The all-red interval provides extra time after the yellow change interval for vehicles that entered on the yellow to clear the intersection before conflicting traffic is released. It does not directly serve pedestrians, reduce cycle length, or increase saturation flow.

Question 44Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is evaluating the need for a dedicated right-turn lane at an intersection. Which factor is most important in this decision?

  1. Pavement type
  2. Left-turn volume
  3. Right-turn volume and conflicting pedestrian volume Correct answer.
  4. Signal cycle length

Explanation

The decision to add a dedicated right-turn lane typically considers right-turn volumes and pedestrian conflicts, as well as crash history. Left-turn volume, cycle length, and pavement type are not the primary factors for right-turn lane warrants.

Question 45Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is using the Highway Capacity Manual method for a two-lane highway. Which parameter is used to adjust for the effect of heavy vehicles?

  1. Driver population factor
  2. Heavy vehicle adjustment factor Correct answer.
  3. Peak hour factor
  4. Lane width adjustment

Explanation

The heavy vehicle adjustment factor accounts for the additional space and performance characteristics of trucks and buses in the traffic stream. Peak hour factor adjusts for flow variation within the peak hour, lane width adjustment affects free-flow speed, and driver population factor adjusts for unfamiliar drivers.

Question 46Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is analyzing a signalized intersection with a cycle length of 80 seconds and a green time of 20 seconds for a given phase. If the saturation flow rate is 1,700 veh/h, what is the capacity of that phase in vehicles per hour?

  1. 850 veh/h
  2. 500 veh/h
  3. 425 veh/h Correct answer.
  4. 600 veh/h

Explanation

Capacity equals saturation flow multiplied by the green ratio (green time divided by cycle length). Here, 1,700 × (20/80) = 1,700 × 0.25 = 425 veh/h. The other options result from incorrect green ratios.

Question 47Traffic Operations Engineering (domain list not enumerated in source)

Which of the following is a key input to the traffic signal warrant analysis for a new signal?

  1. Vehicle and pedestrian volumes on the major and minor streets Correct answer.
  2. Street lighting levels
  3. Sign inventory
  4. Pavement condition

Explanation

Signal warrants are based primarily on traffic volumes, pedestrian volumes, crash history, and other operational factors. Pavement condition, lighting, and sign inventory are not direct inputs to warrant analysis.

Question 48Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is evaluating the safety effectiveness of converting a four-way stop to a roundabout. Which crash type is typically most reduced by this conversion?

  1. Single-vehicle run-off-road collisions
  2. Rear-end collisions
  3. Pedestrian collisions
  4. Right-angle collisions Correct answer.

Explanation

Roundabouts eliminate or greatly reduce right-angle and head-on conflicts by converting them to lower-speed merging and diverging movements. Rear-end collisions may increase or decrease, pedestrian collisions are reduced but not as dramatically, and run-off-road collisions are not the primary target.

Question 49Traffic Operations Engineering (domain list not enumerated in source)

In the context of traffic flow theory, what does the term 'shockwave' refer to?

  1. A device for measuring speed
  2. A sudden change in traffic flow conditions that propagates through a traffic stream Correct answer.
  3. A type of pavement distress
  4. A method for signal coordination

Explanation

A shockwave is a discontinuity in traffic flow, such as the boundary between congested and uncongested traffic, that moves through the traffic stream. It is not a pavement distress, signal coordination method, or speed measurement device.

Question 50Traffic Operations Engineering (domain list not enumerated in source)

A traffic engineer is analyzing a freeway merge. The mainline has a flow of 3,600 veh/h across three lanes, and the on-ramp has a flow of 900 veh/h. If the merge capacity is 4,800 veh/h, what is the volume-to-capacity ratio for the merge?

  1. 1.05
  2. 0.85
  3. 0.75
  4. 0.94 Correct answer.

Explanation

The total demand at the merge is 3,600 + 900 = 4,500 veh/h. The volume-to-capacity ratio is 4,500 / 4,800 = 0.9375, which rounds to 0.94. The other values do not match this calculation.