The maximum toll rate for Interstate 15 express lanes is being doubled to ease commuter crowding around Salt Lake City.
The Utah Department of Transportation says the new rate begins Saturday.
Tolls vary according traffic volume, but the maximum rate for drivers using electronic transponders will go from $1 to $2 at peak times for segments of about 10 miles in length.
The minimum toll during light-traffic times is 25 cents per segment.
UDOT spokesman John Gleason said the move was taken to reduce congestion and increase the average speed in high-occupancy vehicle lanes.
Federal requirements call for speeds above 45 mph, but Gleason says speeds in Salt Lake County can dip as low as 31 mph during peak driving periods.
