Runway Hourly Capacity
Estimate a runway's hourly capacity, C = 3600 ÷ T, from the average occupancy or separation time between successive operations T (seconds). A runway's capacity — the maximum operations (landings and takeoffs) per hour — is one of the most important airport planning parameters, setting the airport's traffic limit. The time T is governed by minimum wake-turbulence separation, runway occupancy time (from touchdown to clearing via a rapid-exit taxiway), air traffic control procedures and the aircraft mix. Well-run single runways reach about 40-60 operations per hour; capacity rises with parallel runways, high-speed exits (reducing occupancy time) and optimized procedures. As demand nears capacity, delays grow nonlinearly (queueing theory), driving expansions or flow management (slots). Enter the average time between operations.
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Runway hourly capacity
The hourly capacity of a runway is C = 3600 ÷ T, obtained from the average occupancy or separation time between successive operations T (in seconds). Capacity — the maximum number of operations (landings and take-offs) a runway can handle per hour — is one of the most important parameters in airport planning, since it sets the traffic ceiling of the airport. The time T between operations is governed by several factors: the minimum wake turbulence separation between aircraft (a light aircraft following a heavy one has to wait longer, because of the wingtip vortices), the runway occupancy time (from touchdown until the aircraft clears the runway through an exit), air traffic control procedures and the fleet mix. A well-operated single runway reaches on the order of 40 to 60 operations per hour; capacity increases with parallel runways, with rapid-exit taxiways (high-speed exits, which cut occupancy time by letting the aircraft leave the runway quickly after landing) and with optimised approach and sequencing procedures. When demand gets close to capacity, delays grow non-linearly (as queuing theory predicts — near saturation, small variations produce large delays), which is what drives infrastructure expansion or flow management measures such as slot allocation at congested airports. Enter the average time between operations.
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Peak Flow Rate (PHF)
Calculate the peak flow rate of a roadway, q = V ÷ PHF, dividing the hourly volume V (vehicles/h) by the peak hour factor PHF (between 0 and 1, the ratio of the hour's volume to four times the busiest 15-minute volume). The result, in vehicles/h, is the equivalent flow rate of the busiest 15-minute period — always greater than or equal to the hourly volume, since traffic does not arrive uniformly. It is the design flow used in capacity and level-of-service analysis by the HCM, since sizing by the hourly average would underestimate the peaks. Enter the hourly volume and the peak hour factor.
Equivalent Flow (PCE)
Calculate the equivalent flow in passenger car equivalents (PCE), q = Q_cars + Q_heavy × E, adding the car flow to the heavy-vehicle flow multiplied by the equivalence factor E (how many passenger cars each truck or bus equals in road occupancy — typically 1.5 to 3.0). The result, in PCE/h, converts a mixed traffic stream into an equivalent homogeneous one, allowing volumes to be compared and the capacity of roads with different traffic compositions to be computed. Heavy vehicles occupy more space and accelerate more slowly, especially on grades. Enter the car flow, the heavy-vehicle flow and the equivalence factor.
Taxi Time on Taxiway
Calculate an aircraft's taxi time on a taxiway, t = distance ÷ speed, from the distance to cover (m) and the taxi speed (m/s). Taxiing is the aircraft's ground movement between the runway and the apron (gate), under its own engines, at low speed. Taxi time is an important component of total operation time and cost: long taxis (at large airports with runways far from the terminal) burn fuel, generate emissions and delays, and occupy capacity-limited taxiways. Taxi speed is typically 5-15 m/s (about 20-50 km/h) on straights, slowing in curves and crossings. Taxi time feeds ground-traffic modeling, taxiway system sizing, ground fuel-burn and emissions estimates, and airport capacity studies. Efficient airports minimize taxi distances and conflicts with good geometry, well-placed runway exits and ground-traffic management. Enter the taxi distance and speed.
Average Headway
Calculate the average headway (time interval between successive vehicles), h = 3600 ÷ q, dividing 3600 seconds by the flow rate q (vehicles/h). The result, in seconds, is the average time between two consecutive vehicles passing a point. Headway is the inverse of flow: the higher the traffic volume, the shorter the intervals. It is a central concept of traffic flow theory, used in signal design, capacity analysis and car-following models. The smallest safe headway defines the maximum capacity of a lane. Enter the flow rate.
Handling Capacity (5 min)
Calculate an elevator's handling capacity over 5 minutes, HC = (300 × Q) ÷ RTT, from the car capacity Q (people) and the round trip time RTT (s). The result, in people carried per 5 minutes, is the standard vertical-traffic performance metric (building peak demand is usually measured over 5 min). The factor 300 is the seconds in 5 minutes. Multiplied by the number of elevators and compared with the building population, it tells whether the system meets demand (typically 12-15% of the population in 5 min in offices). Enter the car capacity and the RTT.
Volume/Capacity Ratio (V/C)
Calculate the volume/capacity ratio (degree of saturation), X = V ÷ C, dividing the traffic volume V by the capacity C of the road or intersection. The dimensionless result measures the road's utilization: X near 0 indicates a free road; X = 1 means the road operating exactly at capacity; X > 1 indicates demand above capacity, with growing queues and congestion. The V/C ratio is the main indicator to classify the level of service (LOS A to F) and identify bottlenecks. Values above 0.85–0.90 already indicate near-saturation operation. Enter the volume and the capacity.
The results provided by this tool are for general informational and educational purposes only and do not constitute professional, financial, medical, legal, tax or accounting advice. Always confirm important decisions with a qualified professional and official sources.