Section 4: Project DesignAnchor: #i1001655
Plans, specifications, estimates, and right-of-way acquisition may proceed once a project has Priority 2 authorization. In this stage of project development, TxDOT completes the design of a facility and acquires right-of-way. Traffic data are required for geometric, pavement, and signalized intersection design.Anchor: #i1001665
For most facility types (controlled access highways, multi-lane non-controlled access highways, two-lane rural highways, and urban arterials), certain aspects of the design are controlled by traffic volumes. Those design features controlled by volume are specific to each project type and are usually determined through a process called design analysis. TxDOT uses design analysis to select the appropriate laneage and lane configurations to ensure that the facility will accommodate the forecast traffic at the desired level of service. The traffic data needed to complete a design analysis include:
- design year traffic forecast of the average weekday daily traffic on detailed network
- design year Directional Design Hour Volumes (DDHV) for each link on the facility including cross streets, and ramps
- design year DDHV turning movement volumes for each intersection
- design year facility peak-hour factor
- percentage of trucks, recreational vehicles, and/or buses for the 24-hour period or for the peak hour.
Traffic Data Provided
- Design year traffic forecast of the average weekday daily traffic on detailed network
- design year AWDT turning movements
- percentage of traffic in the design hour
- directional distribution in the design hour
- percentage of trucks
- design year facility peak-hour factor.