Junction Desing - Term Paper Example

Scenario 2: moderate accompanying refurbishments (low cost) Modifying the immediate major feeder roads to match the expectations of the ideal design for the junction. Scenario 2: Extensive work (high cost) Modifying all the minor and major feeder roads as well as the immediate link areas to major roads to be fed by the junction. Just as the level of work dictates, the three scenarios are more capital intensive as the work increase. However, with more work employed, so is the nearness towards creation of an ideal connection route and hence more effective in meeting public needs.

Extensive work is also expected to create additional disturbances and challenges and hence there is a need to create a balance. The main environmental aspects considered in this report include: geology and soils, surface and groundwater conditions, air quality issues, generated noise, flora and fauna, landscaping and visual impact, cultural heritage, as well the population and general economy (O'Flaherty, 2002, p. 123). This basically involves identification of the environmentally sensitive aspect along the connection route.

It should be noted that no biodiversity areas under national or international legislation protection have been identified as lying along the area of construction. However, usage of natural resources including water resources, agriculturally viable land as well as forests is reviewed in the report. Improvements proposed Design standards for Junction Improvements. Design elements: Channelization: The movement of traffic flow at intersections to specified lanes and paths, by way of traffic marks is referred to as channelization.

Channelization works for segregation of conflicts, regulation of conflict angles, regulation of speed, securing of automotive leaving or crossing the major traffic streams, securing of pedestrians, getting rid of excessive intersectional areas, blocking of prohibited movements as well as positioning of traffic regulation devices (Silver & Corbin, 2008). Design speed: The design speed at the intersection will help in governing multiple elements including entry – exit radius as well as the inscribed diameter.

The design speed at the intersections in this case will vary from 20kmph to 25 kmph. Radius at entry: The radius at entry is defined by the design speed adopted, super elevation as well as the coefficient of friction. The radius should amount to drivers reducing their speeds to the design speed limit of the rotary. A range lying between 15 and 25 m is considered appropriate for the junction in question. Radius at exit: The exit radii should exceed the entry radii in order to enable the vehicles to increase speed while getting off the intersection.

A range lying between 20 and 35 m is to be adopted in the remodeled design. A reduced radius may be chosen if the design speed at the point of exit calls for low speed due to high pedestrian flows as well as the site conditions. Width of carriageway at entry and exit: The carriageway width with regard to the intersection legs is regulated by the design year traffic getting into and leaving the junction. The width at point of entry and point of exit depends on the carriageway width of the approaching road.

The carriageway width with respect to the approaching road is dependent on the number of lanes that needs to be accommodated in each and every direction which largely depends on the volume of traffic entering and leaving the