Traffic Impact Assessment - Examples & Applications

Four consecutive 15-minute approach counts are 100, 120, 140, and 160 vehicles. Calculate the hourly volume and peak-hour factor (PHF) as a classroom descriptive measure.

A counted approach carries $1{,}250\text{ veh/h}$ now. A proposed screening scenario uses 2.0% annually for four years; calculate opening-year no-build traffic before separately identified projects.

For an illustrative 400-dwelling-unit project, a justified local example assumes $r=0.65\text{ veh/(unit·h)}$. Estimate gross peak-hour driveway vehicle trip ends.

An illustrative site generates 900 person trips per peak hour: 20% walk, 25% transit, and 55% vehicle occupants. If each vehicle carries 1.5 persons on average, calculate motor-vehicle trip ends.

A retail site is estimated to make 420 PM-peak-hour driveway trips. A study scenario justifies a 25% pass-by share. Determine pass-by and non-pass-by trips.

Distribute 315 peak-hour trips 55% north, 30% south, and 15% east. Report whole trips that preserve the total.

Before the development, route A carries 180 veh/h and route B 120 veh/h for a common group of travelers. Suppose 60 veh/h are diverted from route A to B with no new regional trips. Determine new flows.

Opening-year no-build demand is 1,353 veh/h on an affected approach. Assignment adds 175 site vehicle trip ends per hour to that approach. Estimate build demand and the increase.

A candidate approach has demand 1,450 veh/h and an assumed effective capacity of 1,600 veh/h in a screening model. Compute demand/capacity and state what else is needed.

An example predicted queue contains 18 vehicles and an assumed average queued space of 6.5 m/vehicle. Available storage is 80 m. Estimate storage need and excess for preliminary review.

A no-build reference volume is 1,000 veh/h and forecast horizon is five years. Compare annual compound growth scenarios of 1% and 3% to test sensitivity.

Average delay in identical scenarios is 43 s/veh no-build, 67 s/veh build, and 52 s/veh mitigated. Calculate the build increment, improvement, and fraction of increment recovered.