Most importantly you need to build a large barrier between the road and your backyard to both soak up and deflect all that noise.
There are a few ways to combat the irritation of unwanted sound. It just depends to what extremes (and costs) you’d like to go to and how bad the noise actually is.
Ideally you would build a tall (3m to 4m) solid concrete wall. The barrier needs to be high as the sound waves will continue to rise and simply ‘roll’ over any fence that is too low. You could then coat this with a specifically designed sound absorbing cover available from many hardware stockists. However, this process can be expensive and planning permission may restrict the height of your fence so make sure you check with your local authority before proceeding.
Alternatively, to save on costs, you could fill in the concrete blocks with insulation foam to act as a sound barrier to the highway. It is very important that there are no spaces in your barrier, so make sure there is no gap at the bottom.
If you’re looking for a more cost-effective and eco-friendly way you can create a wall with hay bales to deaden the noise. Bales with chicken wire weaved through it are far stronger and can also be covered with stucco plaster if so desired. This gives a more attractive appearance than the concrete wall.
If space allows, the addition of plants to your landscape can be an effective method to add to the sound barrier, and also masks any unsightly wall. Evergreens will provide year-round sound deadening with their persistent foliage. Junipers, firs, cedars, and hemlocks all have numerous species that can provide a variety of textures, colours, and densities. Place these on each side for extra absorption.