Trends Spring 2016 - Page 19

One goal of traffic management is to add no more than 15 minutes’ delay over normal operating conditions, said John Davis, a professional traffic operations engineer and Ayres Associates’ manager of traffic engineering services. Ayres’ specialists use traffic microsimulation software, such as Paramics, VISSIM, or Synchro/ SIMTraffic, to analyze how various alternatives might affect motorists, businesses, residences, and construction workers. The analysis calls for extensive information to be entered into the software program: the number of vehicles using the corridor, the percentage of truck traffic, peak traffic times, and anything that might affect traffic flow. “With all that information in hand, we simulate – for example – closing one lane of traffic to allow construction,” Davis said. “What happens?” The construction staging concept, included in the plan let to the contractor for construction, must also consider special events that might affect traffic, such as a local parade or sporting event. The plan notifies the contractor that work schedules may have to be adjusted to accommodate such events. “The contractor is focused on getting the work done, which includes planning the work and scheduling the equipment and crews,” Roth said. “It can cost them – and sometimes our client who pays them – a lot of money and time if they have to unexpectedly stop work because of unforeseen conditions. You coordinate early in the design to address as much of that as possible, and in the end you won’t have as many surprises that will affect the project.” REGIONAL DIFFERENCES NOTED Not all disruptions follow a predetermined schedule. Florida and other states affected by severe storms have hurricane evacuation routes designed to move the maximum number of people to safer regions as quickly as possible. Brian McKee, manager of Ayres Associates’ transportation services in Florida, notes that contractors have to ensure that if a storm approaches, evacuation routes under construction are quickly open and usable, usually within 12 hours of an evacuation notice. How to open the route becomes part of the plan, called maintenance of traffic (MOT) in Florida. The people responsible for creating TMPs have a variety of devices and techniques at hand, with more being added. While most construction zone plans have common elements to consider, the methods used to keep construction workers and motorists safe are tailored for each project. Sometimes detours become the main focus of a TMP because the construction zone is too cramped for other alternatives. That was the case in Cheyenne, Wyoming, during the 2013 construction of a roundabout on TRENDS │19