Traffic noise formula (Traffic Noise Overlay)

The calculations for the Traffic Noise Overlay follow the standard rekenmethode 1 (SRM 1), as described on [1]: --> LAeq = E + Co + Cr - Da - Dl - Db - Dm

where:

• LAeq: equivalent noise level (dB(A))
• E: emission
• Co: acceleration term (default = XXX dB(A))
• Cr: reflection term (omitted)
• Da: distance reduction
• Dl: air reduction (default = XXX dB(A))
• Db: surface reduction (default = XXX dB(A))
• Dm: meteorological reduction (default = XXX dB(A))

Default values are taken from InfoMil [2]

Emission

Emission is computed as:

E = 10 * log(10^(Elv/10)+10^(Emv/10)+10^(Ezv/10)

Per vehicle category, the emission is computed as:

Em = am + bm * log(m/v0) + 10 * log(Q/vm)+Cw;m

and

Cw;m = σm + τm x log(vm/v0,m)

where:

• m: vehicle category (light weihgt, medium weight and heavy)
• a and b: factors to be found at InfoMil [3]

• Cw = road surface correction
• σ = correction factor at reference traffic speed
• τ = correction factor per 10 km/hour deviation from reference traffic speed

Distance reduction

Distance reduction is computed as:

Da = 10 * log(r)

where:

• Da: distance reduction
• r: shortest distance between the source and point of evaluation

References

The overlay calculations are based on Standard Calculation Method 1 (SRM1) as defined by the dutch government: wetten.overheid.nl