This lesson has notes and guides only.
Path Analysis is a tool best used for understanding speeds, g-forces, and trajectories. It produces results based on a path selection.
When you’re done with selecting time periods and path selections you can start the analysis. Just keep in mind load times vary depending on the length and quantity of your paths, and extent of your date range/s.
When you hover over the graph, you’ll notice the little car on the map move along. This is to help correlate driver behaviour with the location. You can see this little car on the g-force and trajectory graphs too!
To know if a g-force incident is considered unsafe, the general threshold is +/- 0.47. You can find out more here.
The Trajectory Graph can only display one path selection.
The measurements are dynamic and respond to the Measurement Settings in the profile button.
Try using the Path Analysis tool to understand vehicle speeds, braking, trajectory, and travel times across the Sydney Harbour Bridge.
Download this file and upload it to the Road Intelligence platform to answer the questions below. If you don't remember how to upload a ciot files, see the instructions here.
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Path Analysis allows you to select any section of road to see driver behaviour, such as speeds, g-forces, and trajectory.
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As mentioned previously, the platform will allocate you a period of time automatically in the Date Selection panel, but if you'd like to add or change this date, you'd either click the add date selection button or you would edit one of the existing selections. You would then also add any exclusions that you'd like.
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Now this is a good example of one of the Help tooltip bars, you'll see that as I've clicked the add path button that a little tooltip has appeared at the top right-hand corner of the screen. You can collapse these or turn them off.
To select a path, you click once to select your origin point and then double-click to select your destination point. In some of the base maps, you'll notice that there are arrows to indicate which direction the flow of traffic is flowing. If you try and select against the flow of traffic, the platform will automatically try and route you in the most logical direction based on the road rules. To get rid of that, you would just click the ‘X’ button in the Path Analysis tool. You also have the ability to change the names and the colours of these paths, and if you have Advanced Modes turned on, you have the ability to upload or download a WKT file.
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Then you would click to analyse your results. This may take a little bit of time, depending on the number of dates you've selected, the length of the date you've selected, but also the number of paths and the length of those paths.
At the top of the Results panel, you have three different options you have your date and time selections, your path selections, and you have your vehicle type selections. If you have exclusions on any of your date ranges, hovering over them in the Results panel will also tell you what those exclusions are.
2:08
The first graph at the top of the page is the Speed Analysis graph, and this shows you information about how vehicle speeds are changing over your selection. There's a couple of options - you have the ability to view All, Average, Median, 85th, and 15th percentile. The All graph will show you a solid line representing the average speed, and then it will show you the upper and lower bounds, which is the 15th and the 85th percentile.
You'll notice in our Speed Over Distance graph that on the map, there is actually a little car icon. As you scrub across the lines on the Speed Analysis graphs, that car will move. This little car icon helps users to identify where that data is corresponding to on the map by indicating it with the little vehicle icon.
You have three graph options. So, besides Speed Over Distance, you have Speed Over Time, and then a Summary Table.
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Now you can actually view multiple date ranges and multiple vehicle types all at once. It does get a little bit messy though - there is a lot of information on these graphs - so we'd recommend if you need to remove some of those elements.
Another advanced feature we have is if you'd like to view two different date ranges for the same path, sometimes the colours can be a little bit hard to distinguish between. So, if you'd hover over that path that you'd want to change the colour for, you can actually make one date range a completely different colour without having to go back and do any edits to the way that you've selected your paths. The labels will also automatically update as well.
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The next graph is Speed Bins. There are two ways that we have displayed the data for Speed Bins. This is speed binning as a bar chart. It shows the percentage of vehicles that are distributed among speed ranges along a selected section of road. It bins the speeds into categories as seen on the x-axis.
Speed binning as a table shows the percentage of the vehicles that fit into each respective speed bin. Vehicle types are separated into separate speed bin tables, and this is broken down by hour as percentages of the vehicles in each bin.
A really good feature to note is that, again, your Measurement Settings are dynamic. So even if you've already processed your results and you've made your road selections, you don't have to re-run the same query again. All you would need to do is go into your Profile Icon and select changing from miles to kilometres an hour or from kilometres an hour to miles per hour.
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The next set of graphs are G-forces, and this shows steering, braking, and acceleration information. Similar to the Speeds Over Distance graph, the G-force Over Distance graph will show you information about the average, 15th, and 85th percentile g-forces. You have a couple of options with these graphs. You can look at the Total, Acceleration, Braking, or Steering, and you can view those for the All, Average, Median, 85th, and 15th percentile. You also have a G-Force Matrix and a Summary Table. You can also compare for different vehicle types, with different road selections, and different dates and times.
The G-Force Matrix helps to visualise speed versus steering, and speed versus braking, as well as a number of other factors to give you an indication about are there any vehicles that are travelling at g-forces that may be considered unsafe. Normally, the threshold for what is considered unsafe is either above 0.47g in the positive direction or below negative 0.47g in the negative direction.
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The Trajectory Analysis graphs show you how vehicles traverse a path and is a high-frequency subset of all of our connected vehicle data. In the trajectory graphs, you have the ability to change the hours of the day. You can either do this by clearing all selections and then adding them back in, or by deselecting selections. You also have the ability to flip the axis. At the top of the graph, there is a key that indicates how many stops those vehicles did, from no stops all the way up to more than three. You have the ability to click on any of these little coloured squares to remove that information from the graph. Please note that for the trajectory graphs at the moment, you can only view one path at a time.
All of these graphs can also be downloaded and saved as a SVG or a PNG file.
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Finally, we have the Travel Time graphs.
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You also have the ability to view the location of your selection on Google Maps. So, clicking this will open Google Maps in a new window, or alternatively, you can export your data. There are a couple of ways you can export this. This is in a storage-optimised CIOT, that means we try and make that file as small as possible. You also have a raw CIOT, and then you have a CSV of all the different paths you've selected. Now again, reiterating that a CIOT is a Compass version of a saved file. By clicking this, it will download a file to your computer. And then what you can do is re-upload this file into the platform using the Upload File button. This will open a dialogue box; the file will appear in your downloads. If you press open, you'll see that the file has now been reloaded.
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