Should schools provide buses to children who live within walking distance?

To walk or to drive, which is better? My kids had been asking me this question since we moved to California, San Jose. Reasons being they hardly see people walking to school; only those that live a stone throw away. For those that live half a mile away from school, the parents/ guardians will drive them to school. They started to think back to when they were in Singapore and how they commuted.
When we were in Singapore, we walked to the supermarket, walked to the train station, walked to the school and even walked to work place if it is less than a mile. Otherwise, we will take public transport as it is so convenient and easily accessed.
After we moved to California, we gave up all the usual practices that we used to do; and started travel around by car even to the nearest grocery store which is only less than 0.5 miles. Reason being the landscape of California is large and public transport is not that accessible in certain places. And, it costs more than driving.
During the last winter, early this year in January, my boys 6 & 7 years old respectively had been talking about walking to school daily. So, they decided to start to walk to school when the spring comes! It's spring! It is the best time of the year to start walking.
Hurray! I walked my boys to school which was about 2 miles from our home. We wake up half an hour early everyday compare to the time we are driving to school. We have our breakfast, get dressed and ready for the walk to school.
After a week later, we have mixed feeling about walking to school. First of all, we in fact benefit from the 45 minutes walk to school. The boys told me they feel so fresh during the class start. And, we have more quality time sharing our thoughts, daily happening and jokes etc.
And, of course, we get teased and laughed at by neighbors, friends and the male classmates. They told us the natives here do not walk such a long distance to school or work. They also commented that we cannot afford a car. And, it is ridiculous to walk 45 minutes daily to school. Worst of all, they scrolled down the car window and wave aat us and laugh every time they pass us. We are greatly affected by such behavior. We felt that we are being humiliated and began to feel discouraged thereafter.
After the few incident, the boys asked me over the dinner table whether we should continue walking to school or drive. I personally feel that walking is an extremely good exercise and asked them to write down on a piece of paper about the pros and cons of walking. After writing down the pros and cons shown below, we decided to continue our plan to walk.
Pros:
Walking is good for health. Walking can improve our relationship (sharing our thoughts, daily happening etc.) Walking can reduce stress and relieve tension. Walking can help to reduce car trips. Walking can help to reduce congestion around the school. Walking can reduce pollution.
Cons: Feel humiliated when peoples laugh at us.
After the comparison, in a nutshell, we should do what is right for us. And, walking is good for our body and good for the earth.