KUSA - Recreational marijuana sales will be legal in Colorado starting Jan. 1. Amendment 64, approved by voters in 2012, threw the doors wide open by requiring state officials to regulate pot like alcohol.

Who can buy marijuana under Colorado law?

Colorado residents 21 and up can buy one ounce of weed. If you're from out-of-state, only a quarter of an ounce can be purchased.

Where can you buy marijuana?

Only nine municipalities and seven counties will allow retail sales. Denver is among them. The city issued a total of 34 retail marijuana business licenses.

The state has approved 348 marijuana business licenses, but most won't be open Wednesday because of local licensing requirements.

How much will it cost?

The system will be regulated, taxed and distributed similarly to alcohol.

Is the personal sale of marijuana under the new law legal?

Selling marijuana (in any form) without a license remains illegal. An adult over the age of 21 is only allowed to sell marijuana with the appropriate license to 21 and up.

Where can you use marijuana?

Amendment 64 does not permit the consumption of marijuana that is conducted openly and publicly. It must be done at home. Under the law it is permitted to consume marijuana on private property unless prohibited by the property owner. Employers can restrict the use of marijuana by employees.

Denver International Airport posted signs letting travelers know it's illegal to use, carry or transport pot at the airport. A civil penalty from the airport could cost up to a thousand dollars and law enforcement would decide on criminal charges.

Can you consume marijuana at social clubs and coffee shops?

No, these businesses are not permitted.

Can you use marijuana at ski resorts?

No, people who smoke in lift lines or on the slopes will be prosecuted. Forest Service officials say the citation costs a minimum of $250.

What are the marijuana DUI Laws?

Driving under the influence of marijuana will remain illegal. You are also not allowed to smoke while driving. Anyone with five nanograms or more of delta 9-tetrahydrocannabinol (known as THC) per milliliter in whole blood while driving can be arrested for DUI.

The blood test is designed to tell how high a person is at the moment, not whether they have been using pot in the last several days or weeks, like urine tests used by some employers.

The blood test measures active THC in the blood stream, while the urine tests measure a metabolite of THC, the form it takes after being broken down by the human body.

Colorado law allows drivers to refuse the blood test. However, that comes with harsher penalties than a DUI.

Can you have marijuana in your car?

Yes, it may be carried but not in an open container and cannot cross state borders. It is illegal to use it in your car.

Does Amendment 64 change existing medical marijuana rules?

The amendment does not change the existing regulations for medical marijuana.

What are the consequences if you violate the marijuana law?

Anything from a fine to possible jail or prison sentence depending on the violation. School, universities, employers are allowed to put their own disciplinary actions into place.

* Information provided by the state of Colorado

(KUSA-TV © 2013 Multimedia Holdings Corporation with The Associated Press)