Citizen.CreateThread(function()

    while true do
        Citizen.Wait(100)

        local veh = GetVehiclePedIsIn(GetPlayerPed(-1))
        local height = GetEntityHeightAboveGround(veh)
        if GetDisplayNameFromVehicleModel(GetEntityModel(veh)) == "POLMAV" then
            if (height > 75) then
                local lCoords = GetEntityCoords(veh)
                TriggerServerEvent('Server:NPAS', lCoords, height)
            else
                TriggerServerEvent('Server:NPASstop')
            end
        end

    end
end)

RegisterNetEvent('Client:NPAS')
AddEventHandler('Client:NPAS', function(lCoords, height)
    local nCoords = GetEntityCoords(GetPlayerPed(-1))
    local hDist = GetDistanceBetweenCoords(lCoords.x, lCoords.y, lCoords.z, nCoords.x, nCoords.y, nCoords.z, false)
    local soundVolume = 0.35
    if (hDist > 0.8) then
        if (height < 150) then
            vDist = 1-((150-height)/75)
        elseif (height > 150) and (height < 330) then
            vDist = ((330-height)/180)
        end

        local hVol = 1-(hDist/500)

        soundVolume = soundVolume*vDist*hVol

        SendNUIMessage({
                transactionType     = 'npas',
                transactionVolume   = soundVolume
        })
    end

end)