Popular ride-sharing companies Lyft and Uber are offering their passengers discounted, and in some cases free, rides on Election Day.

The discounts are available for voters heading to and from the polls on November 6.

An estimated 15 million people were registered to vote in 2016 but couldn't make it to the polls because of transportation issues, according to the CIRCLE study cited by Lyft in a blog post.

Here are the promo codes you need to get a ride during the midterm elections:

Lyft

Lyft teamed up with various voting organizations, such as Vote.org and TurboVote, to distribute a 50% promotion code to riders on their mobile app.

To access your promo code, click here.

Certain underserved communities will be provided free rides through other nonpartisan and nonprofit partners such as Voto Latino, local Urban League affiliates and the National Federation for the Blind.

Lyft is going a step further to provide more information to voters by distributing voter registration handouts at their local Hubs and sending registration reminders through push alerts.

Uber

Uber is offering $10 off one ride to the polls on Election Day, thanks to their partners #VoteTogether and Democracy Works. Riders will have to take the most affordable option available in their city (Express Pool, Pool or UberX, in that order).

You can enter the promotional code is VOTE2018 in your Uber app to get the discount (the promotion is not available in Michigan).

When requesting your ride, you must use Uber's "polling place locator" and go directly to your polling place.