Six states that allow marijuana use legal tests to determine driving while impaired by the drug that have no scientific basis, according to a study by the nation's largest automobile club that calls for scrapping those laws.

The study commissioned by AAA's safety foundation said it's not possible to set a blood-test threshold for THC, the chemical in marijuana that makes people high, that can reliably determine impairment.

Yet the laws in five of the six states automatically presume a driver guilty if that person tests higher than the limit, and not guilty if it's lower.

As a result, drivers who are unsafe may be going free while others may be wrongly convicted, the foundation said.

As Canadian Prime Minister Justin Trudeau and the country's Liberal Party move forward with their big agenda following last year's election, the US's northern neighbor could soon undertake an enormous change in drug policy: marijuana legalization.

Massachusetts voters are split on whether their state should follow suit of states like Colorado, Washington, and Alaska—and legalize recreational marijuana.

According to a Suffolk University/Boston Globe poll Saturday, 43 percent of likely Bay State voters said they would support a likely ballot initiative to legalize the sale of marijuana to anyone more than 21 years old, while 45.8 percent said they would oppose the measure.

Jean Chretien says politicians have to adjust to changing times, as his own views on marijuana, capital punishment and other contentious issues evolved after he was first elected in the early 1960s.

Whether it's pot smoking, abortion, gay marriage or the death penalty, the former prime minister says he's tried to reflect the spirit of the times — even if his changing politics put him in conflict with his conservative upbringing in a large, Roman Catholic family in rural Quebec.

"What were certain values 50 years ago, are not the same today. We have to live with that. It's not always easy," he said.

When asked Monday about Prime Minister Justin Trudeau's decision to legalize the sale of marijuana, Chretien said he is in favour of decriminalization.

Voters will soon be deciding if recreational or medical marijuana is right for their state.

This could be a transformative year in more ways than one. Not only are voters heading to the polls in six months to decide who should become the next President of the United States of America, but voters in quite a few states could be heading to their respective state polls to decide whether or not to expand the use of medical or recreational marijuana within their state.

Former Prime Minister Jean Chretien, left, speaks with former MP Bob Rae during the launch of the MacEachen Institute for Public Policy and Governance at Dalhousie University in Halifax Monday. Chretien said it is time the government decriminalized pot possession.

Former prime minister Jean Chrétien says it's time for Canada to decriminalize marijuana possession, saying the change is long overdue.

Chrétien made the comment today after taking part in a ceremony to mark the official opening of a public policy think-tank at Dalhousie University in Halifax.

The former prime minister says it is unacceptable for anyone to be saddled with a criminal record for simply smoking marijuana.

Thousands of South Africans took to the streets of Cape Town on Saturday, in a procession demanding a relaxation of drugs laws to allow medicinal and recreational use of cannabis.

With some smoking the substance, locally known as Dagga, around 3,000 protesters took part in the march in a backdrop of reggae music, while waving red, green and gold flags.

“We were marching for the legalisation and regulation of cannabis in South Africa,” lead organiser Johannes Berkhout told AFP.

“There is more than enough evidence around the world about the medicinal benefits of cannabis,” he said, adding that legalisation would create a “safer and much more controllable” use of the drug.

Leading academics argue the GOVERNMENT should start selling the drug.

• Ian Hamilton is a mental health lecturer at the University of York 

• Dr Mark Monaghan is a social policy lecturer at Loughborough University

• They say cannabis use is falling but more people are using strong strains

• The government producing marijuana would allow it to control its strength - taking it out of the hands of organised crime and reducing health risks

​It has been linked to schizophrenia and some say it is a gateway to harder drugs.

There are plenty of misconceptions about cannabis laws in European countries. The Czech Republic is a striking example: most foreign visitors think cannabis is legal in this small country in the heart of Europe. But alas, it is not, at least not in the way most international media report. Here are the five biggest myths you should know before you set out on a trip to Prague.

Myth #1: You Can Smoke Cannabis in Public in the Czech Republic

Orlando leaders have voted in favor of decriminalizing small amounts of marijuana.

The City Council voted 4-3 for the measure Monday afternoon. The ordinance is set to take effect Oct. 1.

The change means anyone found with up to 20 grams of marijuana will face a civil infraction rather than a criminal one. Twenty grams of pot is about 30 to 40 joints.

Orlando Mayor Buddy Dyer says the change shows understanding and mercy.

"What we're saying is to someone who has made a youthful mistake for the first time and they have no other background of any sort and are not associated with any crimes we're probably going to be able to give them a second chance," Dyer said.