An additional suggestion is to strive for a "balanced" world population, like a "balanced budget." As population decreases through voluntary prevention and education, less money will need to be spent to build and maintain prisons, power and water treatment plants, roads and waterways. Housing and food and other necessary items would cost less.
Often people are in a hurry, resulting in accidents on the road. The presence of anger, stress, pressure, frustration, doubt and fear don't add to a good environment. People need space to live in, just like animals. There is the option of adoption for those who want to add to their families.