The term "unprecedented" is abused and overused in politics, but two corporations – General Motors-backed Lyft, and Uber (with investment from Google Ventures and Chinese search engine firm Baidu) – attempting to overturn an Austin city policy is unprecedented. Tonight, Austinites see if $9 million can swing a local election.

Prop 1, the proposition pushed by the two transportation network companies (TNCs), could derail the city's plan to introduce fuller background checks on its drivers (the rollback would also remove a series of other regulations of TNC operations, but those have received far less coverage).

With the polls scheduled to close at 7pm, we'll have updates all through the night. Keep refreshing this page, and follow us on Twitter, @acnewsdesk and @austinchronicle.

Update 1, 7pm: Early voting results are in from the Travis County Elections Division (including Austin precincts in Williamson County), and it's bad news for Prop 1 proponents. With a high (for a May 7 single-issue election) turnout of 55,310 (10.86%), early voting stands at 24,076 (43.97%) for the ordinance, and 30,683 (56.03%) against. That means the Uber/Lyft backed proposition is going down by over 12 points, a tough margin for the "yes" vote to overcome.

Update 2, 7:13pm: And now, the breakdown for the early numbers for the Austin population residents in Williamson County. Contrary to the fears of center city Dems that the perceived conservative suburbs would support the measure, it's going down there by a wide percentage: 481 (45.25%) for, 582 (54.75%) against, a 9.5 point spread.

Update 3, 7:41pm: A little bit of number-crunching, courtesy of Travis County. Unsurprisingly for a May election (the city and Austin ISD moved their elections to November exactly because spring races have low numbers), turnout was low. Only one precinct hit 50% turnout, Pct. 364 in West Austin, but that was still only 13 voters.

Looking at the bigger map, Prop 1 did extremely well in the center city (where supporters campaigned heavily), West Campus, and areas of southwest and southeast Travis County. The "no" vote dominated in the north and much of the south, with enclaves out in the southwest corner of the city.

Update 4, 8:03pm: The hits keep coming for the Prop 1 supporters. The first votes are in from election day, and with five precincts reporting, e-day results so far are 427 (37.72%) for, 62.28% against. That means, overall, it's going down 43.84% to 56.16%.

Update 5, 8:10pm: The city has just released a statement from Mayor Steve Adler: "The people have spoken tonight loud and clear. Uber and Lyft are welcome to stay in Austin, and I invite them to the table regardless. Austin is an innovative and creative city, and we'll need to be at our most creative and innovative now."

However, in a show of corporate petulance, per the Austin American-Statesman, Uber is threatening to withdraw from Austin, starting Monday.

Update 6, 8:29pm: One number drops, one number stays (roughly) the same. With 19 boxes reporting, the total vote now stands at 26,017 (43.92%) for, 33,223 (56.08%) against.

Yet while the win/loss stats looks the same, turnout seems to have slowed. In recent years, it's been around a 50/50 split between early and election day voting. This time, e-day turnout has plummeted. With 10% turnout in early voting, the overall numbers seem to be crawling to under 15%.

Update 7, 8:48pm: The downward creep continues for the pro-Prop 1 crew: with 45 of 142 voting locations and 9,705 election day votes in, the measure is now losing 43.81% to 56.19%. That means they're currently at a 7,980 (12.38 point) deficit.

Update 8, 9pm: 64 voting locations reporting, and the numbers seem static: 29,777 (43.85%) for, 56.15% against.

Update 9, 10:09pm: Pro-Prop 1 PAC Ridesharing Works for Austin has released a statement by former Mayor Lee Leffingwell, a paid campaign consultant:

“Unfortunately thousands of people who drive with ridesharing companies to earn much-needed income will now have to find another way to make ends meet. Thousands more of our citizens and visitors from around the world will soon have one less option to get around town safely. "The ballot language written by the City Council was intentionally confusing and a disservice to voters." "We're disappointed in tonight's results. The benefits of ridesharing are clear: reduced drunk driving and economic opportunity. And we won't stop fighting to bring it back."

Update 10, 10:27pm: The final results of the night are in, with a little bit of late-night good news for the losing Prop 1 endorsers, but not enough to change the tide. With all 142 boxes reporting, the latest update from Travis County shows e-day at 14,463 (44.57%) for, 17,990 (55.43%) against. That tightens the overall race up a little bit (44.19% to 55.81%), but the broad 12-point difference remains.

Confirming that Uber will be leaving Austin on Monday, general manager Chris Nakutis issued this statement:

"Disappointment does not begin to describe how we feel about shutting down operations in Austin. "For the past two years, drivers and riders made ridesharing work in this great city. We’re incredibly grateful. "From rallies to phone banking to knocking on doors, they spread the word and their support was humbling and inspiring. "We hope the City Council will reconsider their ordinance so we can work together to make the streets of Austin a safer place for everyone."

Nakutis' statement shows that Uber is prepared to continue its game of brinkmanship. However, the idea that they will leave this to the council seems unlikely. With Austin voting against their attempts to rewrite local ordinances, and Houston mayor Sylvester Turner refusing to blink in the face of similar threats, there is increasing speculation that they will turn to the Legislature for a statewide solution. After all, last session a bipartisan coalition of lawmakers voted to prevent local control over fracking in Denton: With the right lobbying dollars being spent, it seems inevitable that their attention can be turned to this instance of corporate self-interest over local control.

Update 11, 12:44am The final numbers are in from Travis County, confirming what everyone knew: Prop 1 has failed. With only 39,083 (44.29%) of the 88,241 votes cast, the Uber/Lyft-backed measure did slightly better on e-day than in early voting percentage-wise (44.82%, up from 43.97%), but with e-day turnout under two-thirds of early voting, it had little real impact.

Now following Uber's lead, Lyft has announced that it's quitting (or at least suspending operations in) Austin with this statement:

"We're disappointed to share that Prop 1 failed, forcing us to pause operations in Austin as of 5 AM Monday, May 9, until further notice. "We want to thank everyone in Austin – our passengers, drivers, partners, and everyone in between – for all their support over the past few months. We're very disappointed to leave the Lyft Austin community – and we hope to come back soon. If you'd like to help make Austin rideshare-friendly again, reach out to your City Council member and tell them."

However, Austin's council has one supporter. Houston Mayor Turner said, "I applaud the voters of Austin who stood by their mayor and city council in support of fingerprint background checks for Uber drivers. The city of Houston will not compromise on public safety either. Were an election to be held here, I believe voters would choose the same outcome as Austin."