Level Of Service Estimate Calculator

Work out level of service estimate instantly with clear inputs, formula shown and shareable results.

About Level Of Service Estimate Calculator

Level of service grades traffic conditions from A to F using the volume to capacity ratio. Below 0.35 drivers are essentially unaffected by others; above 0.85 small increases in demand produce large increases in delay; above 1.0 the facility has broken down and queues grow until demand falls.

Formulas

Volume to capacity ratio

v/c = demand flow / (capacity per lane x lanes)

Level of service bands

A up to 0.35, B to 0.50, C to 0.70, D to 0.85, E to 1.00, F above

Worked example

With the default values below, Level Of Service Estimate Calculator returns Volume to capacity ratio of 0.3889. Change any input above and every figure here is recalculated in your browser.

Inputs used

Demand flowminimum 0 veh/h: 1,400 veh/h
Capacity per laneminimum 1 veh/h: 1,800 veh/h
Number of lanesminimum 1: 2

Results

Volume to capacity ratio: 0.3889
Level of service: B — reasonably free flow
Total capacity: 3,600 veh/h
Reserve capacity: 2,200 veh/h

Step by step

1Values used
2Volume to capacity ratio
3Level of service bands
4Volume to capacity ratio= 0.3889
5Level of service= B — reasonably free flow
6Total capacity= 3,600 veh/h
7Reserve capacity= 2,200 veh/h

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Level Of Service Estimate figure worked out?

v/c = demand flow / (capacity per lane x lanes). Level of service grades traffic conditions from A to F using the volume to capacity ratio.

Why is level of service E acceptable in cities?

Because building for free flow in an urban area requires land and cost that cannot be justified, and induced demand fills it anyway. Urban design targets are usually D or E at peak.

What values do I need to enter?

This calculator takes 3 inputs: Demand flow, Capacity per lane, Number of lanes. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.