Traffic noise formula (Traffic Noise Overlay)

The calculations for the Traffic Noise Overlay follow the standard rekenmethode 1 (SRM 1), as described on http://wetten.overheid.nl/BWBR0031722/2015-07-01#BijlageIII:

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 [1]

Emission

Emission is computed as:

$E=10\cdot log_{10}(10^{\frac {Ec}{10}}+10^{\frac {Ev}{10}}+10^{\frac {Et}{10}}+10^{\frac {Eb}{10}})$

where:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E} = the combined noise emission

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Ec} = the calculated noise emission for cars

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Ev} = the calculated noise emission for vans

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Et} = the calculated noise emission for trucks

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Eb} = the calculated noise emission for buses

The emission per type of traffic is computed similarly, with values specific to the type of traffic. It is calculated as followed for car traffic:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle Ec = E_{c,start} + E_{c,mult} \cdot log_{10}(\frac {V_c}{V0_c}) + 10 \cdot log_{10}(\frac{Q_c}{V_c}) + \sigma + \tau \cdot log_{10}(\frac{V_c}{V0_c})}

where:

$E_{c,start}$ Emission start value. Configurable with model attribute Emission start (Traffic Noise Overlay). See also: InfoMil [2]

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle E_{c_mult}} Emission factor. Configurable with model attribute Emission mult (Traffic Noise Overlay). See also: InfoMil [3]

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle V_c} = The traffic type's speed, configured in roads with Function Value TRAFFIC_SPEED.

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle V0_c} = The traffic type's reference speed, configured per traffic type using the model attribute V0.

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \sigma} = road surface correction value at reference traffic speed. Configurable in roads with Function Value TRAFFIC_NOISE_SIGMA

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \tau} = road surface correction factor per 10 km/hour deviation from reference traffic speed. Configurable in roads with Function Value TRAFFIC_NOISE_TAU

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

Notes

• If the traffic amount is defined as a single value, that value is used for all defined hours. However, if the amount if an array of values, each of the 24 indexes of that array are assumed to correspond to the hour denoted by those indexes, and as such that specific value from the array is used.

See also

• Traffic Noise Overlay

References

• The overlay calculations are based on Standard Calculation Method 1 (SRM1) as defined by the dutch government: http://wetten.overheid.nl/BWBR0031722/2015-07-01#BijlageIII