Micro-simulation of Traffic - Examples & Applications

Clear Leader–Follower Vehicle Gap

A leader's front is at 95 m along the lane, a follower's front is at 60 m, and leader length is 5 m. Determine the clear gap.

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Clearance Time Headway Diagnostic

A follower maintains s=30 ms=30\text{ m} clear gap at vF=15 m/sv_F=15\text{ m/s}. Calculate the simple clear-gap time diagnostic h=s/vFh=s/v_F.

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Position Advance over a Small Simulation Step

An illustrative model uses Δt=0.50 s\Delta t=0.50\text{ s} with a vehicle moving at a constant 12 m/s12\text{ m/s} during that step. Estimate the travel distance.

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Mandatory Lane Change and a Constrained Gap

A modeled vehicle must merge before a lane end. An illustrative gap-acceptance rule for this single test requires 24 m of usable target-lane gap, while the observed gap is 20 m. Decide whether the modeled change is permitted by this assumed rule.

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Convert Observed Arrivals to an Hourly Input

A field count records 300 vehicles in 20 minutes at a network boundary during a stable demand period. Find the equivalent mean hourly arrival rate.

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Warm-Up and Output Window Accounting

A simulation runs for 90 minutes in total. The first 15 minutes are reserved for warm-up. Determine the reportable observation duration and its fraction of elapsed run time.

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Calibration Travel-Time Relative Error

A base model simulates mean corridor travel time of 8.1 minutes while designated calibration observations show 9.0 minutes. Determine relative error.

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Compare GEH Counts as a Diagnostic

At one count station, observed hourly volume is M=800 veh/hM=800\text{ veh/h} and simulated mean is C=840 veh/hC=840\text{ veh/h}. Compute GEH=2(C−M)2/(C+M)GEH=\sqrt{2(C-M)^2/(C+M)} and explain its role.

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Two-Period Mean Absolute Percentage Error

Observed travel times are 10 and 12 min; simulated values are 11 and 10 min for the same two periods. Calculate mean absolute percentage error (MAPE).

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Independent Queue Validation Decision

Calibration counts match well, but independent validation observations show a peak queue of 12 vehicles when the simulation predicts 9. Calculate the relative difference and decide how to proceed.

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Random-Seed Mean Standard Error

Across 10 independent seed runs, delay has mean 46.2 s/veh46.2\text{ s/veh} and sample standard deviation 3.6 s/veh3.6\text{ s/veh}. Estimate standard error of the sample mean.

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Paired-Seed Alternative Delay Improvement

Four paired runs show baseline minus alternative mean delay improvements of 4, 6, 2, and 4 s/veh. Estimate mean paired improvement and its standard error.

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