Controlled access highways in Illuminatia

Controlled access or limited-access highways, freeways, motorways, speedways, expressways, and other types of high-speed, restrained-access roads dedicated exclusively to non-human-powered vehicles are not a distinct class of roadway in Illuminatia.

While the Automated Terrestrial Traffic Instruction and Control System (ATTICS) is maintained as an entirely-automated all-automobile system of roads, the system does contain a variety of road types, including city streets with at-grade intersections, urban thoroughfares intended only for through traffic, as well as higher-speed rural highways.

Even though ATTICS—by definition of its operational parameters—is technically limited-access, the system has intentionally not been built up to anything resembling the extraordinary freeway systems of late modern-ancient days of Earth's most developed regions. Therefore, freeways and motorways are a foreign concept in Illuminatia.

Freeways with large numbers of lanes and extensive systems of overpasses and ingress and egress ramps are not necessary in Illuminatia, as traffic movements and volumes on ATTICS are strictly regulated in a way that results in extreme efficiency, negating the need for more than two lanes of vehicular traffic in all but the most urban streets.

ATTICS roadways look nothing like the motorways and freeways of Earth, as the fully-automated system is able to share opposing-direction traffic without dedicating lanes to a given direction. In fact, most long-distance rural routes require only one lane of roadway with occasional dual-lane stretches used for overtaking and passing of vehicles at controlled intervals. Additionally, ATTICS manages traffic on converging and crossing paths in such a way that diverging-grade intersections with bridges and overpasses are entirely unnecessary except in some high-volume locations, where such structures do improve throughput; ATTICS instead simply automates traffic such that vehicles on overlapping and crossing paths strictly do not occupy the same space at the same time, and therefore miraculously do not collide with one another.

Illuminatian society values human safety and environmental integrity over convenience and speed of transport. As a result, a system of elaborate freeways was never envisioned as a solution for transportation. ATTICS in conjunction with mass transit and a lack of personal automobile ownership has kept motor vehicle traffic at a highly manageable level that has remained at a level far below a threshold which would make freeways and motorways necessary.