The primary objective of this work was to produce a simulated 4D drive-through of a portion of highway(I-280 through Newark, NJ) for which proposed traffic-generator signing had to be reviewed. A 4D visualization was produced that combined 3D geometry rendering with the time element. Using the simulated drive-through, reviewers (from NJDOT traffic-engineering) were able to see the signing from the point of view of a driver traveling along the roadway at normal traffic speeds. Potential problems regarding excessive density of signing, inadequate sight distances for si going, etc. could then be identified prior to installation of the signs. The 3D geometrical model of the roadway, shoulders, signs, intersecting bridge structures, and other objects of significance was constructed based on available data such as GPS and video log information.

In addition to the I-280 visualization, a second visualization of the exit ramp connecting I-280 to Route 21 in Newark, NJ was also constructed. However, whereas GPS data was used heavily in the modeling of I-280, no such data was available for the exit ramp because it was in the early stages of construction at that time that the visualization was being prepared. Therefore the 3D model of the Rt. 21 ramp had to be built using only construction plans. The goal of the Rt. 21 ramp visualization was to visualize what the project might look like once construction was completed. In general, this type of visualization can be used during public hearings to more clearly educate and inform the public regarding the impact of proposed construction projects.

Once the 3D geometrical models for this project were created, simulated 4D(3D space + time) drive-through of the scenes, including proposed signing, ramps, etc, were constructed. The drive-through simulated the point of view of a driver moving along the roadway at a typical traffic speed. The time element of the simulation, i.e. the speed at which the driver moves through the scene, was an important factor in reviewing the proposed signing for I-280. To ensure that the time element was properly represented, each simulation was generated as a series of movie “frames” which were then combined to form a complete movie. Each frame in the movie was constructed by moving the driver’s point of view to a new position in the 3D model and them rendering the entire scene including perspective projections, hidden surface removal (necessary to evaluate sight-distance checks), color, lighting, shading, and texture mapping. Texture mapping was used to render signs and to add realism to the simulation.

Once all of the frames were generated, they were compressed into digital “software” movies that could be easily played back at the correct speed, or which could be used to produce videotapes of the simulation. The modeling and visualization processes developed during this project demonstrated that 3D modeling and 4D visualization can be very effectively used for design purpose (e.g. traffic engineering design evaluation of proposed signing) and for public presentation purposes. The project also demonstrated that 3D models and 4D visualizations can be created in relatively short time frames.