FE and PE Exam

FE Civil · section 13 of 14 · 9–14 questions

Transportation engineering on the FE Civil

Transportation Engineering is 9–14 questions on how roads are laid out, built and operated: sight distance and curves, pavement design, traffic flow and capacity, signs and signals, and planning. It mixes short geometry calculations with definitions from traffic engineering.

Updated Oct 29, 2026 · Not affiliated with NCEES.

What the section covers

Five topics in the July 2020 specification:

  • Geometric design of streets, highways and intersections.
  • Pavement system design: thickness, subgrade, drainage, rehabilitation.
  • Traffic capacity and flow theory.
  • Traffic control devices.
  • Transportation planning: travel forecast modeling, safety, trip generation.

17 transportation problems

0 / 17 answered · 0 correct
Question 1 of 17 · Transportation Engineering · 9–14 items

A two-lane rural highway has a design speed of 55 mph on a +3 % upgrade. With a perception–reaction time of 2.5 s and a wet-pavement friction coefficient of 0.30, what is the stopping sight distance, and is an available sight distance of 450 ft adequate?

Given
  • Design speed V = 55 mph
  • Grade G = +3 %
  • Perception–reaction time t = 2.5 s
  • Friction coefficient f = 0.30
  • Available sight distance = 450 ft
FindStopping sight distance SSD (ft) and adequacy

Solution

SSD = 1.47Vt + V²/(30(f ± G))

= 1.47 × 55 × 2.5 + 55²/(30 × (0.30 + 0.03)) = 202.1 + 305.6 = 508 ft > 450 ft

FE Reference Handbook, Transportation — stopping sight distance.

576 ft uses f − G, the downgrade case; on an upgrade gravity helps the vehicle stop.
306 ft is the braking distance alone; the 202 ft traveled during perception–reaction was left out.
538 ft ignores the grade; an upgrade shortens braking, so the f + G term should be used.
443 ft keeps speed in mph in the reaction term (55 × 2.5); it must be 1.47 × 55 ft/s.
SSD = 1.47(55)(2.5) + 55²/(30(0.30 + 0.03)) = 202 + 306 = 508 ft, more than the 450 ft available.
Question 2 of 17 · Transportation Engineering · 9–14 items

A rural arterial carries an AADT of 12,400 veh/day. Regional guidance for this functional class gives K = 0.10 and a 60 % peak-direction split. What is the directional design hourly volume (DDHV)?

Given
  • AADT = 12,400 veh/day
  • K = 0.10
  • Directional split D = 60 %
FindDirectional design hourly volume DDHV (veh/h)

Solution

DDHV = AADT × K × D = 12,400 × 0.10 × 0.60 = 744 veh/h

FE Reference Handbook, Transportation — design hourly volume.

DDHV = AADT × K × D = 12,400 × 0.10 × 0.60 = 744 veh/h.
1,240 is the two-way DHV (K × AADT); the directional split was not applied.
1,488 doubles the directional volume (2 × 744), as if both directions carried the 60 % peak share at once.
2,067 divides the DHV by D instead of multiplying.
7,440 applies D to the AADT but skips the K factor.
Question 3 of 17 · Transportation Engineering · 9–14 items

A freeway segment has a free-flow speed vf = 60 mph and jam density kj = 120 veh/mi. Using the Greenshields (linear) fundamental diagram model, calculate the critical density kcrit (veh/mi), the maximum flow capacity qmax (veh/h), and determine whether a measured density of 80 veh/mi corresponds to free-flow or congested regime.

Given
  • Free-flow speed vf = 60 mph
  • Jam density kj = 120 veh/mi
  • Measured density k = 80 veh/mi
FindCritical density, capacity qmax and regime

Solution

q = vf(k − k²/kj); dq/dk = 0 → kc = kj/2 = 60 veh/mi

qmax = vfkj/4 = 60 × 120/4 = 1,800 veh/h

k = 80 > kc → congested. FE Reference Handbook, Transportation — Greenshields model.

kj/4 = 30 is not the critical density; the density at capacity is kj/2.
120 veh/mi is the jam density, where flow is zero; 7,200 = vfkj omits the factor 1/4.
7,200 veh/h is vfkj, four times the Greenshields capacity.
These swap units and quantities: 60 is a speed and 3,600 is vf·kc, not a density.
Greenshields gives kc = kj/2 = 60 and qmax = vfkj/4 = 1,800 veh/h; 80 veh/mi > 60 is on the congested branch.
Question 4 of 17 · Transportation Engineering · 9–14 items

What is the radius of a circular curve if the central angle is 30° and the arc length is 523.6 ft?

Given
  • Central angle Δ = 30°
  • Arc length L = 523.6 ft
FindCurve radius R (ft)

Solution

L = RΔ (Δ in radians) → R = 523.6/(30° × π/180) = 1,000 ft

Equivalent: L = 100Δ/D with D = 5,729.58/R. FE Reference Handbook, Transportation — horizontal curves.

17 ft divides the arc length by Δ in degrees (523.6/30); the arc formula needs Δ in radians.
274 ft multiplies L by Δ in radians instead of dividing.
R = L/Δ = 523.6/(30π/180) = 523.6/0.5236 = 1,000 ft.
2,000 ft uses Δ/2 in the arc formula; the half-angle belongs to the tangent and chord formulas.
Question 5 of 17 · Transportation Engineering · 9–14 items

In the Highway Capacity Manual methodology, what does Level of Service (LOS) 'A' represent?

Solution

HCM levels of service run from A (free flow) to F (breakdown). FE Reference Handbook, Transportation — highway capacity.

Moderate delay with stable but constrained flow is LOS C to D.
Forced or breakdown flow is LOS F.
LOS A is the best operating condition: drivers choose speed freely and delay is minimal.
Unstable flow near capacity is LOS E.
Question 6 of 17 · Transportation Engineering · 9–14 items

A parking lot with 90-degree parking stalls requires what minimum aisle width for two-way traffic?

Solution

Typical 90° module: 18-ft stall + 24-ft two-way aisle + 18-ft stall = 60 ft (ITE / ULI parking guidance). FE Reference Handbook, Transportation — parking.

9 ft is a typical width of one 90° stall, not of the aisle that serves the stalls.
12 ft is a single travel-lane width; two-way traffic plus backing out of 90° stalls needs about twice that.
18 ft is a typical 90° stall depth, not the aisle width.
Two-way aisles serving 90° stalls are typically 24 ft, enough for a car to back out and turn while another passes.
Question 7 of 17 · Transportation Engineering · 9–14 items

An axle-load equivalency table for flexible pavements lists single-axle factors of 1.00 at 18 kips, 1.51 at 20 kips and 2.18 at 22 kips. A design note says: 500 vehicles per day, each with two 20-kip single axles, so daily ESALs = 500 × 1.51. What is the correct interpretation before computing annual ESALs?

Solution

ESAL/day = vehicles × axles/vehicle × LEF = 500 × 2 × 1.51 = 1,510

ESAL/yr = 1,510 × 365 = 551,150

FE Reference Handbook, Transportation — pavement design, equivalent single-axle loads.

The factor applies to an axle of the listed load, not to each kip; and 52 converts weeks, not days.
The design equation takes cumulative ESALs over the design period, so daily values must be scaled to annual (and then over the life).
Each factor is per axle at the stated load; two 20-kip axles contribute 2 × 1.51 per vehicle.
Traffic loads the pavement every day of the year; AASHTO scaling uses 365 days unless counts show otherwise.
Daily ESALs = 500 × 2 × 1.51 = 1,510, and annual ESALs = 1,510 × 365 = 551,150.
Question 8 of 17 · Transportation Engineering · 9–14 items

A contractor proposes mounting a single regulatory parking sign, the only sign on its post, beside a downtown sidewalk where pedestrians walk and cars park, with the bottom of the sign 6 ft above the curb so it clears storefront awnings. What is its compliance status under the national MUTCD?

Solution

National MUTCD mounting height (bottom of a side-mounted sign): at least 7 ft in business, commercial or residential areas where parking or pedestrian movements are likely; at least 5 ft at the roadside in rural areas; a secondary sign mounted below another sign may be 1 ft lower.

In business, commercial and residential areas with parking or pedestrian activity, the MUTCD Standard puts the bottom of a side-mounted sign at least 7 ft above the curb.
The 1-ft reduction is an Option only for a secondary sign mounted below another sign; this is the only sign on the post.
5 ft is the minimum only for roadside signs in rural areas; an urban sidewalk with pedestrians needs 7 ft.
The status is right but the reason is not: the MUTCD minimum there is 7 ft, not 8 ft.
Side-mounted signs have their own minimum heights; overhead signs are governed by vertical clearance.
Question 9 of 17 · Transportation Engineering · 9–14 items

A rural two-lane highway (posted speed 60 mph) needs a curve-warning sign (W1-2). The engineer's draft uses the national MUTCD minimum size for this road type, but the state's adopted MUTCD supplement requires 48 × 48 in for all curve-warning signs on roads with speed limits of 55 mph or more. Which size should be specified, and what documentation is needed?

Solution

National MUTCD sizes are minimums; a state supplement may require larger signs, and the stricter adopted requirement applies. FE Reference Handbook, Transportation — traffic control devices.

The supplement is a requirement, not supporting material; recording it as Guidance misstates the basis.
An adopted state supplement may be stricter than the national MUTCD, and where it is, it governs; the file records the supplement as the basis.
An adopted supplement is binding in that state, for warning signs as for others.
Requesting a deviation from an adopted requirement with no reason is not a design choice; the compliant answer is the larger sign.
The supplement keys the size to the speed limit (55 mph or more), and 60 mph already triggers it; no 70-mph threshold exists.
Question 10 of 17 · Transportation Engineering · 9–14 items

In evaluating pavement performance along transportation corridors, which indicator is most effective in reflecting long-term ride quality and the effects of traffic loading and environmental conditions?

Solution

IRI is reported in in/mi; FHWA rates IRI < 95 in/mi as good and > 170 in/mi as poor. FE Reference Handbook, Transportation — pavement evaluation.

IRI (in/mi or m/km) measures longitudinal roughness, the standard indicator of ride quality, and integrates the effects of traffic and climate.
Skid resistance tracks surface friction and wet-weather safety, not ride quality.
Deflection (FWD) measures structural capacity at a point in time, not the ride quality users feel.
SN is a design index of layer strength; it is not measured as a performance indicator over time.
Question 11 of 17 · Transportation Engineering · 9–14 items

What is the primary purpose of a traffic impact study?

Solution

TIS steps: trip generation (ITE rates) → distribution → assignment → capacity analysis with and without the project → mitigation. FE Reference Handbook, Transportation — traffic studies.

Signal siting may come out of a study, but a TIS is broader: it evaluates the whole effect of a development.
Speed limits are set by speed studies (85th percentile), not by a traffic impact study.
Crash history is the subject of a safety study; a TIS may cite it but its purpose is development impact.
A TIS forecasts trips generated by a development, assigns them to the network and identifies the improvements needed to keep acceptable operations.
Question 12 of 17 · Transportation Engineering · 9–14 items

What is the purpose of a channelized intersection design?

Solution

Channelization: islands, medians and markings that separate conflicts in space. FE Reference Handbook, Transportation — intersection design.

Channelization defines paths and often slows turning traffic; higher speed is not its aim.
Channelization reduces and separates conflict points; increasing them is the opposite of its purpose.
Channelized intersections are often signalized too; islands organize movements but do not replace control.
Islands and markings separate conflicting movements into defined paths, so drivers face one decision at a time.
Question 13 of 17 · Transportation Engineering · 9–14 items

When assessing the viability of a new bus rapid transit (BRT) system within an existing multimodal corridor, which indicator is most critical for evaluating its potential impact on reducing overall traffic congestion?

Solution

Vehicle trips removed ≈ person trips shifted to transit ÷ average auto occupancy, so the modal shift drives the change in road volume.

PHF describes how peaked demand is within the hour; it says nothing about BRT shifting trips off the road.
Congestion falls only if drivers switch to BRT; the share of trips shifting from cars measures that directly.
Occupancy changes with carpooling too; it is an indirect proxy rather than the measure of BRT's effect.
Lane width matters for BRT design, but it does not measure whether congestion goes down.
Question 14 of 17 · Transportation Engineering · 9–14 items

At a signalized intersection, how can actuated signal control strategies enhance corridor performance during periods of fluctuating traffic demand?

Solution

Actuated control uses detectors with minimum green, passage (gap) time and maximum green per phase. FE Reference Handbook, Transportation — signal timing.

A fixed cycle regardless of demand is pretimed control, the opposite of actuation.
Pedestrian intervals are only one part; actuation adjusts vehicle phases as well.
Preset intervals that ignore volume describe pretimed operation, not actuated control.
Detectors extend or end green, skip empty phases and adapt splits as demand changes, cutting wasted green and delay.
Question 15 of 17 · Transportation Engineering · 9–14 items

An unsignalized intersection on a suburban arterial was evaluated with counts from a typical weekday. The Peak Hour warrant is just met, the Crash Experience warrant is not (3 correctable crashes in 12 months), and pedestrian volumes reach 70 % of the Pedestrian Volume warrant. A neighborhood group wants a signal installed immediately. What is the most appropriate engineering recommendation?

Solution

MUTCD Chapter 4C: signal warrants are minimum conditions; meeting one does not by itself require a signal, and an engineering study decides. FE Reference Handbook, Transportation — traffic signal warrants.

No count of four warrants exists; one satisfied warrant can justify a signal, so refusing to study further ignores the data.
The MUTCD states that satisfying a warrant does not in itself require installation; an engineering study must show the signal improves overall safety and operation.
Warrants are checked before installation; a trial signal skips the required engineering study.
Warrants justify a traffic signal, not a beacon, and a beacon chosen without study is not supported by the data.
Meeting one warrant permits but does not require a signal; with marginal results the MUTCD expects an engineering study and lower-cost measures first.
Question 16 of 17 · Transportation Engineering · 9–14 items

A lane closure on a 2.5-mile urban arterial (posted 45 mph) has a 600-ft transition taper with channelizing devices every 20 ft and an 8,000-ft buffer and work area with devices every 80 ft. Counting one device per spacing interval in each zone (no extra end device), how many channelizing devices are needed for the taper and the work area combined?

Given
  • Transition taper length = 600 ft
  • Taper device spacing = 20 ft
  • Work area length = 8,000 ft
  • Work area device spacing = 80 ft
FindTotal channelizing devices (count)

Solution

N = Ltaper/staper + Lwork/swork = 600/20 + 8,000/80 = 30 + 100 = 130

Adding the end device in each zone would give 132. FE Reference Handbook, Transportation — work zone traffic control (MUTCD Part 6).

30 is the taper alone (600/20); the work-area devices were left out.
100 is the work area alone (8,000/80); the taper devices were left out.
Taper 600/20 = 30 plus work area 8,000/80 = 100 gives 130 devices.
160 counts the taper twice (30 + 30 + 100).
430 applies the 20-ft taper spacing to the work area too (8,600/20).
Question 17 of 17 · Transportation Engineering · 9–14 items

In pavement rehabilitation planning for a transportation corridor, what role does mechanistic-empirical (M-E) analysis play in evaluating long-term pavement performance?

Solution

AASHTOWare Pavement ME: climate and traffic inputs → layered-elastic responses → damage via calibrated transfer functions → IRI, rutting and cracking over the design life.

M-E predicts distress accumulating month by month over the whole design life, often 20 years or more.
That is the M-E definition: the mechanistic part computes responses, and empirically calibrated transfer functions turn them into cracking, rutting and roughness over time.
Without field calibration there is no 'empirical' half; transfer functions are fitted to observed performance.
Purely empirical methods, such as the AASHTO 1993 equation, are what M-E was developed to replace.

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Common traps

  • Speed units. Design speed comes in mph, distances in feet: 1 mph = 1.47 ft/s. Forgetting it inflates the reaction distance.
  • Grade sign. In braking distance the grade enters with its sign; a downgrade lengthens the distance.
  • Arc vs chord definition. The degree of curve has two definitions. Highways use the arc definition, and the Handbook formula you pick must match.
  • Superelevation and friction share the load. On a horizontal curve, e + f balances V2/(15R) in USCS units; neither alone does.
  • Flow, speed and density. q = k·v ties them; capacity occurs at the critical density, not at the highest speed.
  • Peak hour factor. It converts an hourly volume into the flow rate of the busiest 15 minutes, so dividing by it never lowers the design flow.

Sources: FE Reference Handbook, Civil Engineering chapter; AASHTO, A Policy on Geometric Design of Highways and Streets; Garber and Hoel, Traffic and Highway Engineering.

Crest and sag are different curves

A crest vertical curve is sized for sight distance over the hump; a sag curve is sized for headlight sight distance at night. The length formulas differ, and each has two cases, depending on whether the sight distance is shorter or longer than the curve. Check the case before you trust the length.

How it connects

Subgrade soils and their testing are geotechnical; asphalt and aggregate as materials are on materials. Profiles, grades and stationing overlap with surveying, and highway drainage and culverts with water resources. Benefit-cost and life-cycle comparisons of projects are on engineering economics.

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