Examples of Indicating Occupied Spacetime in Traffic Simulation Results

Traffic simulations could be beneficial to evaluate systems aiming to improve traffic safety and/or throughput. Possibly the simulation may include rather larger number of vehicles. Especially in the junctions, on a two dimensional Cartesian space, trajectory plots are likely to have intersections with each other. However, the intersections do not necessarily mean collisions; hence, evaluation may require animating the result over a period of time, possibly repetitively. This work aims to add time as one more axis to the plot and indicate space that each road user (a vehicle, a pedestrian, or a personal transporter user) occupies at a given time as a rectangle. In addition, this work would connect vertices of the rectangles of the same road user over time. The resultant plot of the trajectory of one particular road user would be similar to a duct or tube; if a particular road user maintains straight forward trajectory with a non-zero constant speed, it would look like a straight tube with slope. A vehicle making a turn at a corner would be similar to a spatially curved tube. If any intersection of such representation would imply a collision between two road users; thus improving the possibility of explicitly evaluating traffic safety. In the resultant 3D plot, it would be also possible to visually observe propagation of congestion within the traffic flow depending on the situations and/parameters. Regarding the traffic simulation, this work would utilize SUMO open source traffic simulation software with simple junctions. To visualize the traffic, this work would employ matplotlib package of open source SciPy stack for python.