Our field technicians frequently get asked questions like “Can you make the red light by my house shorter?” or “Can you make the left turn arrow longer?” The simple answer to these questions is yes we can! Unfortunately, in most cases, this is not our decision to make. Alterations such as these must first see the necessary requirements met and they are as follows;
A Warrant Study
Before an intersection, crosswalk, streetlight or any device associated with traffic is implemented a warrant study must first be completed. “A warrant study consists of a comprehensive investigation of existing physical and operating conditions. Analysis of the study data provides insight into possible remedial measures, if any. Remedial measures may include various traffic control measures, such as speed zoning, channelization, signing, traffic signals, safety lighting, or a combination of these.” ( onlinemanuals.gov) It is through this study that data on volume, collisions, incidents, pedestrians and so on is collected. In some instances, the warrant study may indicate that a specific product or device is not needed and would therefore not be recommended. Once a minimum criteria has been met, the warrant for the device to move forward is then approved and its off to the next phase, Engineering.
Engineering and Design
The “owner” then assigns the design and design metrics to what is often an in-house engineering firm or it gets awarded to a
third party engineering consultant similar to that of Can-Traffic. In this step, the engineers compile all the data relative to a specific project and use it towards the creation of effective traffic solutions. It is in this phase that the length of time the red stays red would be determined. One complete, the design is then usually re-submitted to the owner again for review and approval. Once all parties are satisfied, construction is given the green light. All the derived data used to create the timings for the “red light” as in our example, now get programmed into the controller and the intersection or device is put into operation.
Reassessment
As city’s and municipalities grow, their populations increase, so to do the traffic volumes. Where the devices in use are not “smart or adaptive” the programming used to create the system may become outdated. This could mean that the red light in question IS in fact too long. So now we’ve come full circle and its back to another warrant study. It would be the objective of this study to determine what timing would better suit the location in question or if the location would be better suited to an adaptive traffic solution. The changes are then made and the process repeats itself. This is the evolution of traffic and this is why your red light takes as long as it does.
