It's been a year since Colorado became the first state in the US to legalise marijuana, and its impact on health, crime, employment and other factors can now be more empirically measured.

So, did it bring about an apocalypse leaving the streets strewn with out-of-work addicts as some Republicans feared?

"We found there hasn't been much of a change of anything," a Denver police officer told CBC this week.

"Basically, officers aren't seeing much of a change in how they do police work."

Not only has the legalisation of cannabis not come with a rise in crime, it has also created thousands of jobs, as tourists flock to the city's 60+ marijuana outlets.

A local newspaper even appointed its first cannabis critic in April.

"So the sky isn't falling?" a CBC reporter asked the officer. "The sky isn't falling," he replied.

Impaired driving, property crime and violent crime were all dropping in Denver prior to legalisation, and the trend has only continued. Even drug use among young people is down, the report claims.

First legal cannabis sales in Washington Show all 10 1 /10 First legal cannabis sales in Washington First legal cannabis sales in Washington Washington's cannabis stores Kevin Nelson, of Bellingham, Wash., holds a sign that reads "Drug War Ends Here," outside Top Shelf Cannabis, Tuesday, July 8, 2014, in Bellingham, Wash. on the first day of legal pot sales in the state. Nelson says he is a long-time activist opposing drug laws, particularly those targeting marijuana users, and he he feels the legalization of marijuana will lead to less crowded jails and be less of a burden on the court system. AP Photo/Ted S. Warren First legal cannabis sales in Washington Washington's cannabis stores A pamphlet titled "Marijuana Use in Washington State," is displayed at the Cannabis City recreational marijuana shop in Seattle. The store will be the first and only store in Seattle to initially sell recreational marijuana when legal sales begin on Tuesday, 8 July, 2014. AP Photo/Ted S. Warren First legal cannabis sales in Washington Washington's cannabis stores Customers shop for marijuana at Top Shelf Cannabis, a retail marijuana store. Top Shelf Cannabis was the first retail marijuana store to open today in Washington state, nearly a year and a half after the state's voters chose to legalize marijuana. David Ryder/Getty Images First legal cannabis sales in Washington Washington's cannabis stores Cale Holdsworth, in town from Kansas to visit family, celebrates after purchasing two grams of marijuana strain "OG's Pearl" for $26.50 at Top Shelf Cannabis, a retail marijuana store David Ryder/Getty Images First legal cannabis sales in Washington Washington's cannabis stores A sign noting the Washington state law that prohibits opening packages that contain marijuana or marijuana-infused products in public rests on a glass case displaying bongs for sale at the recreational marijuana store Cannabis City AP Photo/Ted S. Warren First legal cannabis sales in Washington Washington's cannabis stores Brian Travino, a student at Western Washington University wears a Washington state flag, as he waits with other customers to purchase recreational marijuana at Top Shelf Cannabis in Bellingham, Wash., in the first half-hour of legal sales in the state. AP Photo/Ted S. Warren First legal cannabis sales in Washington Washington's cannabis stores Amber McGowan, left, and Krystal Klacsan, right, work at the recreational marijuana store Cannabis City in Seattle to apply a state-mandated frosted film to the front of a display case that will contain pot varieties when legal sales begin on Tuesday, July 8, 2014. The store will be the first and only store in Seattle to initially sell recreational marijuana on Tuesday. AP Photo/Ted S. Warren First legal cannabis sales in Washington Washington's cannabis stores A customer, who declined to give his name, sniffs a strain of recreational marijuana at Top Shelf Cannabis, Tuesday, July 8, 2014, in Bellingham, Wash., during the first half-hour of legal sales in the states. Customers cannot be given samples, but are allowed to use "sniff jars" to help make their purchasing decisions. AP Photo/Ted S. Warren First legal cannabis sales in Washington Washington's cannabis stores Julian Rodriguez, right, of Everson, Wash., holds his two-gram packet of recreational marijuana outside Top Shelf Cannabis, Tuesday, July 8, 2014, in Bellingham, Wash., on the first day of legal sales. At left is Tom Beckley, the owner of the store. AP Photo/Ted S. Warren First legal cannabis sales in Washington Washington's cannabis stores The price of two grams of a strain of marijuana named "Sweet Lafayette," is displayed at Top Shelf Cannabis, Tuesday, July 8, 2014, in Bellingham, Wash., on the first day of legal sales of recreational marijuana in the state AP Photo/Ted S. Warren

Colorado's unprecedented move led to Washington, Alaska and Oregon voting for legalisation, and this week a bill was filed to legalise it in New York.