Possible North Bethesda, Maryland Automated Microbus Application

Automated Microbus system
Automated Microbus system.  Click image for larger version. For largest version click here.

Monorail alternative from 1992 study
20 mph (32 kph) monorail alternative from 1992 study of the same corridor.

A possible North Bethesda, Maryland Automated Microbus application connects a heavy rail station with an office park and regional mall. The proposed 6-passenger Microbus has a 25 mph (40 kph) top speed and runs at 5 second minimum headways. The technology is only a small step beyond Automated Road Vehicles that have entered passenger service in Europe and Japan. The Microbus is narrow and only requires a 15 ft (4.6 m) right of way for two lanes. It's based on an off-the-shelf electric vehicle chassis, and is guided by precise steering along an exclusive light-duty road.

The above image of the Microbus system covers an area of 2.5 by 0.9 miles (4.0 by 1.5 km). Because of the scale, the two-way Microbus route is only shown as a single line. The width of this line is exaggerated in the relatively small image on this page above, but is shown to scale in larger versions.

Western terminus of Microbus systemTo properly display system details, such as the center barrier between the two lanes, an even higher resolution is desirable. This makes it difficult to show the entire system at one time. The image at the right gives a detailed view of just the western terminus, which would serve a regional mall. Five vehicles can be seen waiting at the station.

All Microbus trips would be non-stop, origin to destination. During peak periods, Microbuses are shared, while in the off peak vehicles are available on demand and most trips are single party. A surcharge for private service is possible. Stations use 45-degree, back-out docking, so all berths operate independently. Vehicle design and operating policies follow accepted APM standards. Acceleration and jerk limits are set for standees, although a low profile results in most passengers being seated. Snow is removed with plows and blowers.

The North Bethesda application is similar to the generic Beltway Shuttle concept, although it does not literally run along a beltway. The Microbus roadway is entirely two way, and is located mostly at grade alongside freeways. Four of the five stations are located at grade at the ends of short branch lines. The North Bethesda alignment is described in detail here. It's estimated that because of the limited number of Microbus stations, an average vehicle occupancy of five passengers could be achieved for trips to and from the heavy rail station.

The corridor has been previously studied by the local planning agency for a possible monorail or automated light rail system. The executive summary of the study is available here. The alternatives were estimated to cost between $64 million and $82 million in 1990 dollars, and carry between 11,000 and 14,000 daily passengers by the year 2020. They were expected to eliminate the need for 2,000 parking spaces. Microbuses appear to offer comparable peak period service to these systems, as well as better off-peak service, lower costs, and much lower visual impact.