Since 2012, used cars have been taxed based on their book value instead of their sales price, which is usually higher.

Under the new law, buyers who go to a used car dealer will pay taxes on the sales price unless the dealer finances the sale. In that case, the tax will be calculated based on the book value of the car.

Person-to-person sales, from a neighbor or someone on Craigslist, would also be taxed at the lower book value.

The car tax changes resulted from a compromise between new and used car dealers after years of public fights and expensive lobbying at the General Assembly.

Hundreds of laws approved this year already took effect July 1, including measures to prevent landlords from evicting tenants, raise the minimum marriage age from 16 to 17, and allow medical marijuana sales to registered patients.

Here’s a look at some other laws that start on New Year’s Day:

— Drug pricing companies called pharmacy benefit managers must reveal to insurers and other clients how much money they receive from pharmaceutical manufacturers and how much of that they're not passing on to patients, according to House Bill 323.

— Elected county officials will receive a 5% raise of their base salaries, according to Senate Bill 171. Those officials include sheriffs, tax commissioners, superior court clerks and probate court judges. Their base salary ranges are set at $35,576 in small counties and $131,099 in large counties. Many officials also receive local supplements in addition to their state mandated base salaries.

— Remote medical treatment by phone or computer, called telehealth, could expand after the approval of Senate Bill 118. The measure requires insurers to reimburse telehealth providers at the same rates as the same service received in-person. In addition, insurers will not be allowed to force patients to use telehealth services.

— Gwinnett County, the second-largest county in the state, will add an 11th superior court judge, according to House Bill 21.

One law that doesn't go into effect Jan. 1 is the state's ban on most abortions once a doctor can detect fetal cardiac activity, usually at about six weeks into a pregnancy and before many women know they're pregnant.

A federal judge blocked House Bill 481 based on the U.S. Supreme Court's precedent in the Roe v. Wade case, which prevented states from restricting abortions before a fetus is viable, between 24 and 26 weeks of pregnancy. The case could eventually be decided by the U.S. Supreme Court.