Traffic Impact Study

 

With time, new development and re-development in various areas of a city or township or even rural areas takes place. These developments may cause further traffic burden on the existing traffic, thereby, causing traffic congestion in the area. Based on the Traffic Impact Assessment, improvement in roadway is identified so that traffic operations in that area remains safe and efficient upon completion of the project. 

The traffic impact study should remain objective assessment (means must be carried out at later stage when required) and should not merely act as means of getting approvals for planning and construction activities of the development.

The cost of these improvements is borne by the developer in form of either cash paid to local authorities or the developer approves drawings of the development from local authorities and construct the required improvement to prevent the wastage of public tax money.

The traffic Impact Assessment shall be mandatory carried out for commercial areas, institutional areas, residential societies, industrial areas during planning and approval stage of the proposed development. Small developments such as houses have very little impact on the existing traffic and can be usually be ignored.

 Example: For above development, the five identified points will need to be analyzed

WHAT IS INCLUDED IN TRAFFIC IMPACT STUDY? 

Traffic Impact Study should contain but not limited to following sections:

• Description of the Project (site plan including subdivisions if applicable) 

• Identification of Study Area (map showing study site and area) 

• Horizon Year and Time Period (usually 25-year or 50-year) for Analysis 

• Existing Traffic Conditions

• Background Traffic Demand – Existing traffic and its projection in Future

• Site Generated Traffic Demands – for current year and its projection in future

• Total Traffic Demand – summation of traffic from above 2.

• Evaluation of Impacts of Site Generated Traffic

• Analysis of feasible Location of Access to site 

• Alternatives required for Mitigation of Traffic Impact

a.      Traffic impact for background traffic (future case)

b.      Traffic impact for total traffic

                                                    i.     Without mitigation

                                                   ii.     With mitigation

• Recommendations

CLASSIFICATION

Traffic impact studies are classified into two types:

Traffic Impact Assessment

It deals with interaction of traffic generated by development with road network and intersections on the road.

Traffic Impact Statement

It deals with access/exit of development, internal road network within development and parking details as per guidelines.

 SOFTWARES

Various softwares such as Autodesk Infraworks, Trafficware Synchro, TransModeler and PTV Vissim & PTV Visum may be used for studying the various scenarios.

 

Creating Alignment Using AutoCAD Civil 3D

 

AutoCAD Civil 3D is industry's top software by Autodesk for various types of engineering projects such as roads, highways, motorways, stormwater sewer, sanitary sewer etc. These projects can be classified as Infrastructure projects.

 An Alignment is a Civil 3D entity in two dimension and describes centerline of road or pipe. It's important to create an alignment accurately, as it determines the final layout of the project.

In this article, we will briefly discuss the various options available in autoCAD Civil 3D for creating of Alignments.

Creating an Alignment:

To create an alignment, follow these steps:

• Open the AutoCAD Civil 3D software and click on the Home > Create Design > Alignment button.

Alignment Command

• It will open a menu as shown below:

Alignment Creation Menu

• This menu contains various options for creating an Alignment. I have numbered these options from 1 to 10. Let me describe these one by one briefly.

• Alignment Creation Tools

It is used to create New Alignment using Tangents and Curves from scratch. It prompts for creation of Tangents and Curves with different options. Also compare it with Create Alignment from Objects.

 This is one of the most frequently used option.

• Create Best Fit Alignment

If your alignment is very simple alignment and regression equations can be used to describe geometry of your Alignment. Otherwise, you will need to split up your alignment into smaller parts and use the "Create Best Fit Alignment" option. 

• Create Alignment from Objects

This option can be used to create Alignment from other objects such as Polyline, 3D polylines and Feature lines already created in the drawing. It is also one of the most frequently used options used to create alignments.

• Create Alignment from Corridor

In certain cases, Alignment needs to be created from feature lines of a corridor. This option will create alignment from feature line of a corridor. 

• Create Alignment from Network Parts

To represent Network parts on a profile, an alignment will be created so that we can draw its profile and project the network parts on that profile. Further labels can be added to the profile. 

• Create Alignment from Pressure Network

This option is same as Network Parts but will create Alignment from Pressure Network parts.

• Create Alignment from Existing Alignment

This option can be used to create Alignment from existing Alignment. 

• Create Offset Alignments

Offset Alignments are created for various functions such as widening.

• Create Connected Alignment

Connected alignment can be created using this option. It will associate the alignment with each other at the intersection point and their profile at intersection point will have same elevation. These profiles can be raised or lowered at the same time. It comes handy in creation of intersections.

• Create Widening

It also creates an offset alignment will widening options.

  Further details of each option can be checked on Autodesk website.