Some retailers geofence their stores so they know when a shopper has walked in. The Bonnaroo Music and Art Festival geofenced the entire state of Tennessee so it knew when its concert-goers were en-route.

Bonnaroo is a four-day musical festival where 85,000 people campout while enjoying music from 10-plus stages across the 700 acres during the day. For the past two festivals in 2014 and 2015, the musical festival has used beacons and geofencing to communicate with its attendees, and get an idea of how people are moving across the concert area. Beacons are small pieces of hardware that can be placed anywhere and that send messages to consumers who move past the beacon if they have the company’s app downloaded and opted in to receive messages. A geofence is a digital “fence” it puts around an area so it knows when consumers have entered.

80% of concertgoers drive to the venue, and 90% of them are from out of state, so it helps the event organizers to know when all these festival-goers are going to show up is a good idea, says Jeff Cuellar, vice president of strategic partnerships at AC Entertainment LLC, an entertainment agency that produces Bonnaroo. Cuellar discussed how using beacons and geofences enhanced the music festival for concertgoers at the Connect Mobile Innovation Summit in Chicago yesterday.

Besides the state of Tennessee, the concert also geofenced the airport so it could send a welcome message to festivalgoers once they landed. Organizers placed 114 beacons around the venue, including along the highway leading up to the concert gates, Cuellar said. Since Bonnaroo provides its own signs for the event along the road, it could easily attach beacons to the signs that cars are passing. The roadside beacons sent messages telling drivers that they are so many miles away and they should pull over into the right lane now because the line for turning off will begin soon or they are 30 minutes from the gate while they are sitting in a traffic line and they should get their tickets ready to make the process go faster.

The beacons on the concert premise helped consumers locate the nearest water stations or medical tents. They also provided AC Entertainment with data on where people were inside the venue and how fast the lines were moving. Organizers can use the data for the next year to better lay out concessions and manage lines, Cueller said. The venue also experimented with the range of beacons, from six feet away to less than a foot, depending on what the message was.

About 80% of the festivalgoers downloaded the app, Cuellar told Mobile Strategies 360 after the presentation. And of those consumers who downloaded the app, 25% opted in to receive push notifications for the 2015 concert in June. That was an increase from the 18%-20% who opted in when the concert first employed beacons in 2014.

AC Entertainment learned a lot from that first year about beacon messaging, including that more messages are not necessarily better, he said.

“People were getting too many messages, and it was detracting from their experience,” Cueller said of the first year it tried the technology.

Based on the feedback it received, AC Entertainment scaled back the number of messages it sent by 80% for the 2015 festival and sent no more than four messages per day, he said. If there had been an emergency, or the venue had to be evacuated, he could have overridden this limit, Cueller said. AC Entertainment did away with some messages that it thought were entertaining and cute, but did not provide useful information to festival attendees, he said. For example, Bonnarro generically labels places at the venue, such as “Which Stage” and “That Tent,” and while AC Entertainment thought delivering clever messages, such as “You just passed Which Stage, did you mean to go to That Tent,” were funny festival goers did not, Cueller said.

AC Entertainment deployed the Bonnaroo beacons through its app vendor, Aloompa. Deploying beacons cost in the tens of thousands of dollars, which Cueller said is a worthwhile investment.

For other companies, such as retailers or restaurants, considering beacons, Cueller cautions them that they are not going to persuade every customer to accept messages, and that it is hard to measure the return on investment.  He said companies should consider the value of the data they are getting from the beacons, such as where people are, and how they can make that data useful, instead of expecting it to directly affect their sales.