--- title: How to simulate roundabout in Road description: "![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image8.jpg?resize=1024%2C683&ssl=1) *Image taken from Zutobi.com* A roundabout is a type of loop road, which is also known as a ring road. Loop road is commonly required to control traffic flow and provide access to specific areas. For a road to…" url: "https://mes100.com/docs/simulate-roundabout-mes-road/" updated: "2024-07-11" category: Modelling Techniques / Road --- # How to simulate roundabout in Road ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image8.jpg?resize=1024%2C683&ssl=1) *Image taken from Zutobi.com* A roundabout is a type of loop road, which is also known as a ring road. Loop road is commonly required to control traffic flow and provide access to specific areas. For a road to be considered in a loop, the **Start and End points should be at the same location**, forming a complete circle. # **Steps on designing Roundabouts in Road module** Example of a roundabout project [**here**](https://largefilehosting.s3.ap-northeast-1.amazonaws.com/ProjectSharing/Client%20Project%20-%20Saiful/Roundabout-backup-2.10.45.0-070823114603.zip). Designing roundabouts in MiTS is quite similar to designing curvy roads. The key difference is that for roundabouts, users will create the Road CenterLine (Horizontal Line input) with the **Start and End points at the same coordinates** as illustrated in the image below. ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image9.png?resize=1024%2C633&ssl=1) ## **S1: Setting up project file with original topography** - Open the Road module - Import the Survey Points to represent the original topography of your development area *Input* > *Survey Points & Soil Info* > *Import Manage* **User may refer to User Guideline, *[**Steps to Import Survey Data**](https://mes100.com/docs/survey-points-import/#6-toc-title)* ## **S2: Define the road and its CenterLine** - At the Left Side Panel, define a road under the Project View. From the image below, we will be working on '**Road 2**'. ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image11.png?resize=1024%2C389&ssl=1) - Create the CenterLine by creating a few IP points circling the roundabout. (*Please refer below on how the IP points will be located*) *Road Input* > *Horizontal* > *Line* (*Please note that the Start and End are located at the same point*) ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image1-1.png?resize=605%2C462&ssl=1) ## **S3: Define a suitable Design Radius and Transition Length** - Once all the IPs have been input, please go to *Horizontal Alignment*> *Curve* > *Spread Input* ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image2-1.png?resize=1024%2C571&ssl=1) - Do note that you will need to change the design standard*,*design speed, design radius, and spiral length to suit the roundabout condition. - If the roundabout requires a design radius *smaller* than the Min. Radius stated under the Spread Input, go to *Properties tab at the RHS Panel > Change the Min. Radius Standards from JKR to None* ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image5.png?resize=1024%2C541&ssl=1) ## **S4: Design the Vertical Alignment** - Then, you may start to design your vertical alignment as in the image below. ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image4.png?resize=1024%2C543&ssl=1) ### **Possible Verification Error for Vertical Alignment** Shown below, is the Verification Error that you may receive when designing the Vertical Alignment for a loop road. ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image10.png?resize=1024%2C508&ssl=1) Please note that **both Start and End VIP for loop roads are the same**, so you only need to define either ONE for closed roads. # **What if the Start and End points of the Horizontal Line are not the same?** A *not properly closed* loop road may be one of the possible modeling errors that users face when designing for a loop road. In this situation, despite having the same X and Y coordinates for the Start and End points, they will be considered as two different entities. ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image7.png?resize=1024%2C363&ssl=1) To ease users in simulating a loop road in our **latest MiTS 3**, the software has been improved with auto-detection for a close road. Once the software detects the Start and End points of a road to be closely placed, a *message will be prompted* asking users if the points need to be merged as in the image below. ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image3-1.png?resize=1024%2C323&ssl=1) Furthermore, an *AutoFix* feature has also been implemented to resolve self-intersects road verification error (The Start and End points are overlapping but not merged) as in the image below. ![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/07/image6.png?resize=1024%2C143&ssl=1) # **Tutorial Video for reference** User may also refer to the video below; [https://www.youtube.com/embed/Z8JrSHcn7Hg?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent&enablejsapi=1](https://www.youtube.com/embed/Z8JrSHcn7Hg?version=3&rel=1&showsearch=0&showinfo=1&iv_load_policy=1&fs=1&hl=en-US&autohide=2&wmode=transparent&enablejsapi=1) # **Related topics** - [**Open Loop in Road**](https://mes100.com/docs/open-loop-in-road/) ### *Related* [![](https://i0.wp.com/mes100.com/wp-content/uploads/2024/10/me-small.jpg?resize=100%2C100&ssl=1)](https://mes100.com/author/admin/)[Ngu Soon Hui](https://mes100.com/author/admin/) I’m the [Benevolent Dictator for Life](https://en.wikipedia.org/wiki/Benevolent_dictator_for_life) for MiTS Software cum Editor of this website. Read more [here](/about-ngu-soon-hui/). You can also contact me at soonhui@mes100.com