HARD CASE TRANSPONDER. Hard case transponders are the more prevalent type of transponder, given that they have been in circulation longer and because some of the new tolling schemes being implemented necessitate their use. These transponders are small hard plastic cases that typically attach to the inside of the windshield via Velcro and contain the necessary electronic components to be read by a wayside (i.e., roadside) toll tag reader to identify the user and record the transaction. Each transponder is set with a unique independent electronic signature that is linked to a specific user account. The transponders currently used for all of the toll facilities in Colorado are plastic cases approximately 3 x 3.5 inches with batteries. Some hard case transponders have the ability to be disabled (i.e., turned on or off) or switched into a different mode (i.e., allow users to declare their status as SOV or HOV while still transmitting a signal to the reader,). For example, the Express Pass used along I-15 in Salt Lake City, Utah has the ability to be turned on and off depending upon vehicle occupancy. The Utah Express Lanes are free if two or more people are in the vehicle, but a toll is assessed for SOV users. With the tab pulled down on the transponder, the tag is disabled and cannot be detected by the wayside toll tag reader. In an attempt to make enforcement easier, when the pull tab is in the off position, the opposite side of the transponder is red. This allows the enforcement personnel to visually confirm the transponder position and then visually confirm that the vehicle occupancy matches the transponder setting. It should be noted that video tolling cannot be used with this type of transponder since the wayside reader does not detect a disabled transponder and it simply appears as if no transponder is present. The FasTrak multi-mode hard case transponder is anticipated to be deployed in California’s Bay Area for managed lanes on I-580 and I-680. Similar to the I-15 Express Pass, the FasTrak transponder allows users to perform self-declaration. However, the difference is that this particular transponder has a switch that changes the declared occupancy in the vehicle from SOV to HOV2 and HOV3+. For all three modes, the tag is still read by the wayside reader and the occupancy of the vehicle is registered by the system. Since the tolling system registers the occupancy of each vehicle, video license plate tolling can be used for all users that do not have a transponder.
