IOWA CITY — Like many of us, Mormon Trek Boulevard won’t go on a diet until after the holidays. Iowa City’s project to take the four-lane street on Iowa City’s west side down to three lanes is on hold until the spring as the city waits for new traffic signals to be delivered, said Scott Sovers, senior civil engineer for the $1.6 million project.“We initially thought we could get the lane conversion done this fall, but there is some signal modification that needs to happen,” Sovers said.