We can now measure what happens when pot is legalized, and the picture is pretty bright.

The great social experiment that is marijuana legalization is now five years old, with six states already allowing legal marijuana sales, two more where legal sales will begin within months, and yet another that, along with the District of Columbia, has legalized personal possession and cultivation of the herb.

As a number of state legislatures—including Connecticut, Delaware, New Hampshire, New Jersey, New Mexico, and New York—seriously contemplate joining the parade this year, it’s more important than ever to be able to assess just what impact marijuana legalization has had on those states that have led the way.

The prophets of doom warned of all manner of social ills that would arise if marijuana were legalized. From hordes of dope-addled youths aimlessly wandering the streets to red-eyed carnage on the highway, the divinations were dire.

And they were wrong. In a report released Tuesday, From Prohibition to Progress, the Drug Policy Alliance takes a long look at just what has happened in the states have legalized weed. It’s looking pretty encouraging:

1. Marijuana arrests plummeted.

Well, of course. If there’s one thing you could predict about legalizing marijuana, this is it. The decline in the number of pot arrests is dramatic: 98 percent in Washington, 96 percent in Oregon, 93 percent in Alaska, 81 percent in Colorado, 76 percent in D.C. That means tens of thousands of people not being cuffed, hauled away, and branded with lifelong criminal records, with all the consequences those bring.

The savings in human liberty and potential are inestimable, but the savings to state criminal justice and correctional systems are not: The report puts them at hundreds of millions of dollars.

2. But the racial disparities in marijuana arrests have not ended.

While marijuana legalization dramatically reduces the number of people arrested for marijuana offenses, it clearly does not end racially disparate policing. The vast disparities in marijuana arrests remain, even in legal states. Black and Latino people remain far more likely to be arrested for marijuana offenses than white people, despite similar rates of use and sales across racial groups. There is work to be done here.