Monday brought the start of a month of free rides on all Regional Transportation District buses and trains, kicking off a promotion aimed at getting metro Denver residents to reduce time spent in their cars.

More than a dozen transit agencies statewide are joining RTD in suspending their fares for at least a month. Underlining the state-funded initiative’s goal of helping to clear the air, fare-free August began on an ozone health alert day for much of the Front Range corridor.

“The Zero Fare for Better Air program saves people money, reduces traffic and pollution, and expands access to public transit,” Colorado Gov. Jared Polis said in a news release.

At least those are the hopes as RTD and other agencies emulate fare-free promotions tried out by other U.S. transit providers, including in Salt Lake City earlier this year.

So far Monday, scattered reports on social media indicated typical ridership levels on some RTD trains and buses during the morning rush hour. But riders on others did report higher-than-usual crowds.

Transit providers are still struggling to come back from pandemic drops in ridership. RTD also is dealing with short staffing, security challenges and other problems that its leaders worry could mar the promotional month.

RTD all month is waiving its normal fares, which range from $3 for local trips to $10.50 for the A-Line to the airport. The agency says it’s working out credits for participants in monthly pass programs, since passes won’t need to be scanned during August.

Colorado lawmakers this spring approved legislation setting aside $28 million to help offset the costs of at least a month of fare-free programs at the height of ozone season this summer and again in 2023.

While most of that will go to RTD, the Colorado Association of Transit Agencies says more than a dozen smaller public transportation providers also are participating, including those serving Colorado Springs, Greeley, Pueblo and Durango.

Some smaller agencies are using the money to test out new routes and services, too.

Sixteen transit agencies across Colorado already provide fare-free rides throughout the year, many of them in mountain towns. This month, that will balloon temporarily to 30 agencies, CASTA says.

“During August, Colorado transit agencies are excited to roll out the largest zero-fare program in the country, saving our current riders money and encouraging new riders to discover how transit connects them to their community,” said Ann Rajewski, the organization’s executive director, in a news release last week.