FOXBORO - U2’s two-day visit to Foxboro started uneventfully Sunday night.

State police had made no arrests at Gillette Stadium as of 9 p.m., shortly before the 360 Tour concert started, said Lt. David Wilson, state police spokesman.

Foxboro police said they had no arrest information at press time.

Wilson said concert traffic backed up Route 1 north around 9, but it was unclear how far the snarl went. He believed traffic would start flowing once the concert started.

Route 1 reportedly was backed up after the parking lots opened at 3 p.m. Stadium officials had warned that fans arriving before 3 p.m. would be turned away.

The stadium gates were scheduled to open at 5 p.m.

The same restrictions apply to tonight’s concert, which Foxboro police expect to be more challenging because it coincides with the evening rush hour.

The event is expected to draw about 65,000 fans each night, including 7,000 fans on the field.