How to convince my parents to let me live near campus instead of commuting?

You and your parents should be aware that UCI adjusts financial aid if you live with your parents and commute.

Using the UCI NPC at http://www.ofas.uci.edu/content/Calculator_Dependent.aspx?nav=0 , if I put in some financial parameters that produce about $20,000 in grants (leaving about a $10,250 net price) for off-campus living, changing it to living with parents produces about $15,000 in grants (leaving about a $10,250 net price).

Obviously, this is based on UCI’s assumption that living with your parents and commuting is $5,000 less expensive than living off-campus (note that living with your parents is not free, in that you consume food and utilities, and have commuting costs). Actual costs for living off-campus versus living with your parents and commuting may be significantly different from what UCI assumes, so you and your parents need to calculate net costs yourselves.