When the darkness falls …

Planning to stake out a good spot to view the total solar eclipse next month? You won’t be alone—and officials are warning that the massive public interest could lead to hours of standstill road traffic, airspace crowded with leisure and commercial pilots, and disruptions at a host of airports.

The Federal Aviation Administration has warned that air traffic delays are likely on April 8, when the eclipse will sweep through North America from Mexico to Canada and plunge a narrow path into complete darkness in the middle of the day.

On the roads, federal authorities are asking for the public’s help to avoid gridlock across several states.

“While an estimated 32 million people live within the path of totality, millions more will travel to see the event first-hand,” Shailen Bhatt, administrator of the Federal Highway Administration, said. “This rare event may be a once-ina-lifetime for some, but could have widespread impacts on the traveling public. So please plan ahead to arrive early and, if you can, stay put to avoid traffic congestion.”

Around the last total solar eclipse to reach the U.S., in 2017, motorists clogged roadways along the path in multiple states immediately after the show. Some rural routes experienced more than 15 hours of congestion, with backups stretching for up to 70 miles.

Some cities have been planning for an influx of visitors for more than a year before the upcoming eclipse. Some local governments in Texas have declared a state of emergency ahead of time.

The state of Oklahoma is warning residents of longer emergency response times, potential disruptions to cell coverage and overwhelmed roads.

The FAA is asking airlines and pilots to plan ahead and file a preferred route to help reduce delays, and to monitor notices and temporary flight restrictions.