Automated Control of Transit Buses Could Cut Costs, Raise Safety

The same experimental electronic devices that can control the movement of cars could be used to operate and maintain transit buses, according to a Raytheon E-Systems engineer.

This week, automated highway system (AHS) devices that could control movement, speed and navigation of cars is being demonstrated in San Diego for the 1997 AHS Demonstration. Raytheon engineer Robert Larsen says preliminary tests show similar equipment could be used for hands-free driving of transit buses through bus-only lanes. The devices also could guide buses through service facilities for routine maintenance, reducing labor costs. Another possible application could be an automatic collision avoidance system.

The automated systems for transit buses are called Advanced Vehicle Control Systems (AVCS). "While vehicle control has been extensively developed for rail/guideway-based vehicles like trains and Automated People Movers, relatively little automation technology has been applied to buses," Larsen said. "Likewise, despite underlying similarities among buses, automobiles and trucks, the significant work performed in vehicle control for passenger cars has largely gone untested for buses. On the one hand, this is surprising, given the sensitivity of transit operators to incremental improvements in operating efficiency - improvements that appear achievable through the application of AVCS. On the other hand, there is typically little funding available for the development of new transit technology, with available funds more likely spent on low-risk systems that show a more immediate return on investment."

An Inexpensive Alternative to Light Rail

Only a small amount of engineering work has been done on how to control transit buses with automated devices. Most of it was by a firm called O-Bahn, which has deployed automated buses in Adelaide, Australia; Essen, Germany; and the United Kingdom.

The O-Bahn system provides automatic lateral control on express segments of bus routes and manual control elsewhere. Special bus and roadway modifications are needed for automatic operations. The electronically-guided buses follow a current-carrying wire in the pavement using an inductive guidance principle. Because the guided buses deviate only slightly from their busway lanes, only a narrow right-of-way is required, which reduces infrastructure costs by allowing guided busways to be built in relatively small spaces. "As a result, O-Bahn systems may be viewed as a favorable alternative to light rail in some transit corridors," Larsen said.

While researching AVCS for transit buses, Larsen interviewed transit executives nationwide.

"Once the AVCS concept was thoroughly explained, the overall consensus of the transit community was that AVCS showed exciting potential for the distant future, but much less promise for the immediate future," Larsen said. - "The more visionary planners imagined dramatic service and operating cost improvements with guided buses running on busways and subway tracks and automated buses moving assembly line-style through maintenance garages." Several American cities could use AVCS systems with only moderate modifications to their infrastructure.

Pittsburgh - "Of transit properties studied, the Port Authority Transit (PAT) system is one of the most suitable for AVCS deployment," Larsen said. "PAT operates the only dedicated and grade-separated busways in the country, providing an excellent testbed for vehicle control testing and development."

Houston - "With its well-funded and heavily bus-oriented transit system, Houston is currently the only regional transit agency spending research and development funds on the development of AVCS," Larsen said. "Houston METRO is scheduled to participated in the 1997 AHS Demonstration with laterally- and longitudinally-guided buses based on machine vision and forward-looking radar sensors. They have also expressed serious interest in the testing of automated movement of buses within maintenance facilities."

Seattle - "The unique 1.3-mile bus runnel/subway and attached busway segment are exclusive bus facilities that show potential safety and efficiency benefits from AVCS," Larsen said. "The automated service garage concept was also of interest to Metro planners."

Although great potential exists for the technology, barriers of technical feasibility and institutional skepticism of new technologies remain, Larsen said. For more information, call Robert Larsen at (703) 560-5000, ext. 4315.