An automated highway system (AHS) or Smart Road is a proposed intelligent transportation system technology designed to provide for driverless cars on specific rights-of-way. It is most often touted as a means of traffic congestion relief, since it drastically reduces following distances and thus allows more cars to occupy a given stretch of road.

How it works

In one scheme, the roadway has magnetized stainless-steel spikes driven one meter apart in its center^{[citation needed]}. The car senses the spikes to measure its speed and locate the center of the lane. Furthermore, the spikes can have either magnetic north or magnetic south facing up. The roadway thus has small amounts of digital data describing interchanges, recommended speeds, etc.

The cars have power steering and automatic speed controls, which are controlled by a computer.

The cars organize themselves into platoons of eight to twenty-five cars. The platoons drive themselves a meter apart, so that air resistance is minimized. The distance between platoons is the conventional braking distance. If anything goes wrong, the maximum number of harmed cars should be one platoon.