FORT LAUDERDALE — The artificial turf zone along Las Olas known as Tunnel Top Plaza cost taxpayers nearly $12.7 million — an extra $2 million more than expected. City officials hoped the pricey addition would transform the area that sits atop the U.S. 1 tunnel into a trendy gathering spot. But some residents, including the mayor, are less than impressed with the current bunker-like look. Tunnel Top Plaza, the new pedestrian plaza that sits above the Henry E.