Transportation Engineering Simulations

A collection of interactive 3D visualizations and simulations to help you master concepts in transportation engineering.

Highway Geometric Design - Theory & Concepts - Cross Section

Principles of cross-section elements, horizontal alignment, and vertical alignment.

Highway Cross-Section Builder

Lanes per Direction:2

Lane Width:3.6 m

Shoulder Width:3 m

Divided Median5 m

Highway Geometric Design - Theory & Concepts - Sight Distance

Principles of cross-section elements, horizontal alignment, and vertical alignment.

Stopping Sight Distance (SSD) Simulator

Adjust the parameters to see how velocity, reaction time, road friction, and grade affect the total distance required for a vehicle to come to a complete stop.

Design Speed (V)60 km/h

Reaction Time (t)2.5 s

Coeff. of Friction (f)0.35

(Lower = wet/slippery, Higher = dry/rough)

Grade (G)0%

(- = Downgrade, + = Upgrade)

Reaction Dist.

41.7 m

Braking Dist.

40.5 m

Total SSD

82.1 m

Visual Representation

Perception-Reaction

Braking

250m Scale

Highway Geometric Design - Theory & Concepts - Superelevation

Principles of cross-section elements, horizontal alignment, and vertical alignment.

Superelevation Calculator

Design Speed (V): 80 km/h

Curve Radius (R): 400 m

Results

Max Safe Friction ($f_{max}$):0.14

Required Superelevation ($e$):0.0%

Safe

F_c

Cross-section view (exaggerated forces)

Highway Geometric Design - Theory & Concepts - Vertical Curve

Principles of cross-section elements, horizontal alignment, and vertical alignment.

Vertical Curve Profile

Initial Grade ($g_1$): +4%

Final Grade ($g_2$): -3%

Curve Length ($L$): 400 m

Curve Type:Crest

Algebraic Diff ($A$):7.0%

K-Value ($L/A$):57.1 m/%

High Point at $X$:228.6 m

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PVC

PVI

PVT

High Pt

Highway Geometric Design - Theory & Concepts - Mass Haul

Principles of cross-section elements, horizontal alignment, and vertical alignment.

Mass Haul Diagram Simulator

Visualize cumulative earthwork volumes along the alignment.

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Interpretation: A rising line indicates excess cut material available for hauling forward. A falling line indicates a need for fill material. When the curve crosses the red zero-line, cut and fill volumes are exactly balanced at that station.

Highway Capacity and Level of Service - Theory & Concepts - L O S

Concepts of capacity, level of service (LOS), and analysis of highway facilities.

Level of Service (LOS) Simulator

Current LOSB

Avg Speed68 mph

"Reasonably free flow. Freedom to maneuver is slightly restricted."

Traffic Density15 pc/mi/ln

Based on Highway Capacity Manual (HCM) density thresholds for basic freeway segments.

Intersection Control and Design - Theory & Concepts - Intersection Visualizer

Principles of intersection design, conflict points, and control types (stop, yield, roundabouts).

Intersection Control and Design - Theory & Concepts - Conflict Point

Principles of intersection design, conflict points, and control types (stop, yield, roundabouts).

Conflict Point Simulator

Intersection Type

4-Leg Cross Intersection

Crossing Conflicts:16

Merging Conflicts:8

Diverging Conflicts:8

Total Points:32

The traditional cross intersection has a high number of crossing conflicts, which are the most dangerous type.

Crossing (High Severity)

Merging (Med Severity)

Diverging (Low Severity)

Traffic Signal Design - Theory & Concepts

Principles of signal phasing, timing, and capacity analysis for signalized intersections.

Traffic Signal Timing Simulator

Adjust the cycle length and phase distributions to observe how green, amber, and all-red clearance intervals allocate time to competing traffic streams at an intersection.

Cycle Length ($C$)60 sec

East-West Green Phase30 sec

Amber Phase3 sec

All-Red Clearance2 sec

Time: 0s / 60s

North/South

🛣️

East/West

E/W Green

N/S Green

Traffic Signal Design - Theory & Concepts - Signal Timing

Principles of signal phasing, timing, and capacity analysis for signalized intersections.

Traffic Signal Timing Simulator

Timing Design Parameters

Cycle Length (

C

)60 sec

Green Split (

g_1 / g_{total}

)0.60

Calculated Timings:

Total Lost Time ( $L$ ): 8s
Phase 1 (N-S) Green: 31s
Phase 2 (E-W) Green: 21s
Yellow per phase: 3s
All-Red per phase: 1s

T = 0s / 60s

North-South

East-West

Cycle Ring Diagram

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Public Transportation Systems - Theory & Concepts - Transit Fleet

Overview of public transit modes, characteristics, capacity, and operations.

Transit Fleet Size & Scheduling Simulator

Adjust the route parameters to see how running time and layovers dictate the required fleet size to maintain a specific headway.

Round-Trip Running Time50 min

Required Layover/Recovery10% (5 min)

Desired Headway (h)10 min

Total Cycle Time (

T_c

)55 min

Theoretical Vehicles (

T_c / h

)5.50

Required Fleet Size (

N

)6 buses

Actual Scheduled Headway9.2 min

Resulting Frequency (

f

)6.5 buses/hr

Transportation Economics - Theory & Concepts - Economics B C A Visualizer

Economic evaluation of transportation projects, cost-benefit analysis, and user costs.

Benefit-Cost Analysis Visualizer

Adjust the parameters to see how discount rates and project life affect the Present Value (PV) of benefits and the overall B/C Ratio.

Initial Capital Cost ($)$15.0M

Annual Benefits ($)$2.50M/yr

Discount Rate (r)6%

Design Life (n)15 years

Present Value Comparison

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Net Present Value+$9.28M

B/C Ratio1.62Project Justified ✓

Pavement Design - Theory & Concepts - Flexible Pavement

Principles of flexible and rigid pavement design, ESAL calculations, and the AASHTO method.

AASHTO Flexible Pavement Design

Design Inputs

Traffic (ESALs):5 Million

Subgrade $M_R$:5,000 psi

Lower $M_R$ means weaker soil, requiring a thicker pavement.

Reliability ($R$):90%

Layer Thicknesses (inches)

Surface ($D_1$, $a_1=0.44$):4"

Base ($D_2$, $a_2=0.14$):6"

Subbase ($D_3$, $a_3=0.11$):8"

Required SN:0.00

Provided SN:0.00

✅ DESIGN ADEQUATE

30" -

20" -

10" -

0" -

HMA Surface (4")

Base Course (6")

Subbase (8")

Subgrade$M_R$ = 5000 psi

Pavement Design - Theory & Concepts - Rigid Pavement

Principles of flexible and rigid pavement design, ESAL calculations, and the AASHTO method.

Rigid Pavement Thickness Calculator

Traffic Loading (ESALs)15 Million

Higher traffic volume requires a thicker slab to prevent fatigue failure.

Concrete Flexural Strength (S'c)4.5 MPa

Stronger concrete can withstand higher tensile stresses without cracking.

Modulus of Subgrade Reaction (k-value)40 MPa/m

Stiffer subgrade/subbase provides better support, reducing required thickness.

Include Dowel Bars (Load Transfer)

Tied Concrete Shoulders

Required Slab Thickness

250 mm

250 mm PCC Slab

Subbase / Subgrade (k = 40 MPa/m)

Load Transfer Coefficient (J): 2.8

* Simplified calculation for educational purposes.

Pavement Design - Theory & Concepts - Aggregate Grading

Principles of flexible and rigid pavement design, ESAL calculations, and the AASHTO method.

Aggregate Gradation Visualizer

Select a gradation type to see its characteristics.

Characteristics: Dense-Graded (Well-Graded): Contains a continuous distribution of aggregate sizes from coarse to fine. This results in minimal void space and high stability due to aggregate interlock.

Railway Engineering - Theory & Concepts - Track Structure

Principles of railway track structure, train resistance, geometric design, and operations.

Railway Track Structure

Controls

Track Gauge (mm): 1435

Narrow (1000)Standard (1435)Broad (1676)

Highlight Component:

Info

The track structure distributes immense point loads from the wheels safely to the subgrade.

←1435 mm Gauge→

Railway Engineering - Theory & Concepts - Train Resistance

Principles of railway track structure, train resistance, geometric design, and operations.

Train Resistance (Davis Equation)

Train Type:

Speed ($V$): 60 km/h

Track Grade: 0%

Even a 1% grade dramatically increases total resistance for heavy trains.

Total Resistance at 60 km/h

196 kN

Aero ($CV^2$)36

Flange ($BV$)60

Rolling ($A$)100

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Airport Engineering - Theory & Concepts - Runway Length

Principles of airport planning, runway orientation, length corrections, and geometric design.

Runway Length Correction Simulator

Basic Length:1800 m

Elevation:600 m MSL

Air density decreases at higher altitudes.

Reference Temp (ART):24°C

Std. Temp at 600m is 11.1°C.

Effective Gradient:0.6%

Sequential Corrections

1. Elevation Corrected:2052.0 m

2. Temp Corrected (Applied to #1):2316.7 m

3. Gradient Corrected (Applied to #2):2455.7 m

Final Required Length:2455.7 m

+36.4% penalty

BASIC

0m2455.7m