Disclaimer: Stolen from several sources.
The Road is a strange space between the mortal world and the various outer realms. The Road is a reflection of the mortal world, but stained by emotions, events, and locations of magic. A place where great violence took place might have ethereal bloodstains, bullet holes, or even phantom corpses long after the original crime scene vanished. A place devastated by economic ruin might appear run down, dilapidated and desolate.
Any supernatural character can step onto the Road by concentrating for a moment and making a TN 3 Magic test. The character can step off the Road with a similar roll. In areas that are magically heavy or mystical in nature, the TN might be lower or even automatic. Similarly, supernatural dead zones might require a higher TN, or the Road may simply be inaccessible ... or perhaps not even exist in that locale.
Creatures on the Road are invisible to mortals. Supernaturals can peer onto the Road with a TN 3 Perception roll (characters with The Sight can do this automatically) While doing so, they see the real world with the Road partially imposed on it, and can see creatures on the Road clearly enough to identify them. However, opening one's perception to the Road allows creatures on the Road to see the observer clearly as well. Ordinarily individuals in the real world appear as blurry, shadowy outlines. No physical interaction is possible between individuals on and off the Road; they will simply pass through one another as if they weren't there.
While the Road exists as the nexus between various realms, modern supernaturals have embraced it as a means to covertly go about their business. Inhuman creatures can hide indefinitely on the Road without drawing attention to themselves. Combat, goblin markets, and all manner of things best not seen my mortal eyes also happen on the Road.
Ordinary electronics do not occur on the Road; cameras, phones, GPS, and the like simply glitch out. However, some shady mortal organizations have developed goggles and similar devices that allow mundane operatives to peer onto the Road. Rumor has it that some of these organizations are working on ammunition that can be fired onto the Road, devices that allow humans to step onto the Road, and even stranger gadgets.