The Vote for Prop 1 campaign added Mothers Against Drunk Driving (MADD) to their list of supporters a day ahead of the May 7th election.
The campaign has consistently credited ridesharing companies like Uber and Lyft with reducing drunk driving in the city.
Travis County Sheriff Greg Hamilton has said the same.
At a December council meeting, Police Chief Art Acevedo seemed to favor that notion over the main point of contention in this fight: fingerprinted drivers.
"Fingerprinting obviously, it provides another layer. You have bio-metrics. But I think it's a misnomer to say without fingerprints there isn't a background. Both of them have their pros and cons, I think they're both good. Having both would be great but I think the worse thing that could happen would be to lose 10,000 options for our citizens at 2:00 in the morning," Acevedo said to applause from the crowd.
Vote for Prop 1 has said drunk driving collisions decreased 23% in 2014 compared to 2013.
But APD says that data changes often. New numbers from police show 597 DWI crashes with arrests in 2013...523 in 2014. Only a 12% drop.
Dr. Matt Hersh, a UT statistician with the Our City, Our Safety, Our Choice group, encouraging voters to say "no" to Prop 1 says the numbers aren't a good example anyway.
"DWI accidents, DWI arrests were decreasing well before Uber and Lyft started operating in Austin. And there's absolutely no evidence of any impact that they've had or any correlation between Uber and Lyft and DWI's," Hersh said.
Amy George with MADD believes on the national level, ridesharing is making a difference.
"We have research that we've looked at from California to Miami. And in California alone, 1800 lives have been saved since Uber entered the market there. That information validated by a third party group is undeniable," George said.
On Thursday, Lyft sent a text to drivers telling them if Prop 1 doesn't pass the company will leave the city at 5 am Monday morning. We asked Lyft driver Diane Young what that will mean to her.
"That we'll be down at the City Council building trying to get it back. We will not stop fighting. It's too important," Young said.
The Our City, Our Safety, Our Choice PAC sent a statement about Lyft's text to their drivers saying in part:
"The timing of Lyft's threat to leave Austin is ironically similar to Uber's threat to leave Houston. The timing of both announcements is obvious attempts to frighten voters and influence the outcome of the Prop 1 election. These types of corporate tactics are an insult to the people of Austin."
As we've reported Uber and Lyft have poured millions of dollars into the Vote for Prop 1 campaign.
According to the Travis County Clerk's office, nearly 58,000 people voted early.
The polls are open from 7 to 7 on Saturday.