People usually think of subways as the exemplar of inner-city rail transit. Subway systems are expensive and are practical only in cities with large populations. Subways move quickly, stopping every quarter-mile to let passengers on or off. Monorails run on a single, usually raised, rail. It is a misconception that anything on a raised track is a monorail; according to the Monorail Society, monorails "are wider than the guideway that supports them."
Although subways are not particularly advantageous, due to cost, they still are capable of carrying large groups of people quickly. Monorails have additional benefits; they are safe and eco-friendly, and monorail designs prevent them from derailing by directly attaching them to the track. They are more cost-effective than their regular subway counterparts.
Bus rapid transit, or BRT, is an alternative to rail rapid transit. BRT differs significantly from subways or monorails; according to the National BRT Institute, it is a hybrid of rail designs and buses. Unlike subways and monorails, it uses buses or bus-like vehicles on roads or special lanes.
The National BRT Institute explains that BRT has significant advantages over rail transit, the largest of which is reduced cost, compared to subways or monorails. The system's technological novelty should also attract new passengers, thereby reducing traffic. Although these vehicles rely on fossil fuels, they will still reduce greenhouse gases by using hybrid engines.
