Maintenance of Traffic for Innovative Geometric Design Work Zones, 2015

Currently there are no guidelines within the Manual on Uniform Traffic Control Devices (MUTCD) on construction phasing and maintenance of traffic (MOT) for retrofit construction and maintenance projects involving innovative geometric designs. The research presented in this report addressed this gap in existing knowledge by investigating the state of the practice of construction phasing and MOT for several types of innovative geometric designs including the roundabout, single point urban interchange (SPUI), diverging diamond interchange (DDI), restricted-crossing left turn (RCUT), median U-turn (MUT), and displaced left turn (DLT). This report provides guidelines for transportation practitioners in developing construction phasing and MOT plans for innovative geometric designs. This report includes MOT Phasing Diagrams to assist in the development of MOT strategies for innovative designs. The MOT Phasing Diagrams were developed through a review of literature, survey, interviews with practitioners, and review of plans from innovative geometric design projects. These diagrams are provided as a tool to assist in improving work zone safety and mobility through construction of projects with innovative geometric designs. The aforementioned synthesis of existing knowledge documented existing practices for these types of designs.

Addendum to the Design Manual for Low Water Stream Crossings, HR-247, 1984

The purpose of this manual is to provide guidelines for low water stream crossings (LWSC). Rigid criteria for determining the applicability of a LWSC to a given site are not established nor is a 'cookbook" procedure for designing a LWSC presented. Because conditions vary from county to county and from site to site within the county, judgment must be applied to the suggestions contained in this manual. A LWSC is a stream crossing that will be flooded periodically and closed to traffic. Carstens (1981) has defined a LWSC as "a ford, vented ford (one having some number of culvert pipes), low water bridge, or other structure that is designed so that its hydraulic capacity will be insufficient one or more times during a year of normal rainfall." In this manual, LWSC are subdivided into these same three main types: unvented fords, vented fords and low water bridges. Within the channel banks, an unvented ford can have its road profile coincident with the stream bed or can have its profile raised some height above the stream bed.