Demonstrates Automated Bus Rapid Transit Technologies
by Steven E. Shladover
researchers demonstrated some of the key technologies for automated
bus rapid transit (A-BRT) services for invited visitors in San Diego
on the weekend of August 23-24. This demonstration continued a distinguished
PATH tradition of demonstrating the most advanced ITS capabilities under
realistic conditions on full-scale vehicles, and true to that tradition
it exceeded the expectations of the visitors.
has equipped three transit buses with the sensing, actuation, communication
and computation systems needed to enable them to operate under completely
automatic control. At the same time, these buses were equipped
with a specially-designed driver-vehicle interface (DVI) system to show
how easy it is for the driver to interact with the automation systems,
to transfer back and forth between normal manual driving and automation
and to initiate automated maneuvers such as lane changing on the highway
and precision docking at local bus stops.
emphasis of this demonstration was showing the realistic opportunities
for implementation of the A-BRT technologies to improve transit service
and economics. Since the demonstration buses were two standard-size
(40 foot) buses powered by compressed natural gas (CNG) and one 60-foot
articulated bus powered by a diesel engine, it was also possible to
show how the automation technologies can harmonize the performance of
these very different vehicles so that they can operate close together
in an electronically-coupled "virtual train".
Here to see a demo of the Automated Bus Platoon. (Real
transit service functions that were demonstrated included:
docking of a bus at two different platforms, one representing
an in-line platform at a bus terminal and the other representing
a curb-side platform requiring an approach with a lane change ahead
of a line of parked cars. In both cases, the bus stopped with a
gap of less than an inch between the bus floor and the platform,
making it easy for one of visitors to roll on and off the bus in
a wheelchair. Both the steering and the stopping of the bus were
controlled automatically, although initial deployments of this service
would probably only use the automated steering function, leaving
the full attention of the driver for watching out for pedestrians
Here to see a video of Precision Docking (Real
lane-keeping (or lane assist) of the buses operating in a line-haul
mode on the I-15 HOV lanes. This demonstration showed the ability
of the automatic steering system to keep the bus centered accurately
over the lane, while providing a smooth ride for the passengers. This
is an important capability to enable buses to operate in narrow lanes
where right of way is costly or unavailable. The driver was able to
switch back and forth between automatic and manual steering at will,
showing how a driver could override the automatic system when necessary.
lane-changing while operating on the highway, initiated by the
driver pressing a button on the DVI. In order for buses to be able
to enter or exit from an A-BRT bus-way, or from off-line stations,
it is necessary for them to be able to change lanes automatically.
This part of the demonstration showed the ability to execute this
maneuver repeatedly, with a minimum of effort required by the driver.
Here to see a video of Automatic Lane Changing (Real
automated bus driving. The buses were operated in both low speed
(docking) and high speed (highway driving) conditions with fully automatic
steering and speed control. Once the driver transferred control to
the automated system, he did not need to do anything else until reaching
the other end of the HOV lanes, where he regained control. This capability
indicated the potential for future operations without requiring a
driver to be on every bus operating along a dedicated, protected bus-way.
However, the technology is not yet sufficiently mature and fault-tolerant
to make it possible for our drivers to leave the driver's seat (except
in the limited case of the low-speed precision docking maneuver).
"virtual train" of buses. The diesel bus was electronically
"coupled" behind one of the CNG buses for a run down the
length of the I-15 HOV lanes (8 miles), making use of a "WiFi" wireless data link, combined with forward-looking lidar and radar
sensors to detect the gap and speed difference between the buses.
The buses ran at separations of 40 m and 15 m to each other and smoothly
performed the automatic transitions between these two different target
separations. The operations at the 15 m separation showed the potential
for automated bus trains to carry very high passenger volumes in the
highest- density corridors. With that length of separation between
the buses in the "virtual train", and with a long enough
separation between consecutive bus trains to ensure that no failure
would involve more than one bus train, a sequence of three-bus trains
could provide 70,000 seats per hour in one lane, which is competitive
with the highest-volume rail transit services.
visitors who participated in this demonstration included members of
the Board of Directors of ITS America and the Program Steering Committee
of the Cooperative Vehicle-Highway Automation Systems (CVHAS) pooled-fund
project, as well as the attendees of the TRB meeting on "Urban
& Community Transit - The Role for Automated BRT". The reactions
of the visitors were very enthusiastic. For example, Neil Schuster,
the President and CEO of ITS America, said,
San Diego demo went very well and I know our members enjoyed it; this
is the fourth time I've seen the technology in action, and each time
I'm amazed - now I can tell friends I rode in a city bus, going down
a real highway at speed, too close to a bus in front of us for a human
driver to attempt. For me, the expression on someone's face the first
time they comprehend they are in a moving vehicle without
a driver is priceless! What a great morning!"
discussions in the TRB meeting that immediately followed the demonstration
were strongly influenced by many comments indicating that the demonstration
changed people's minds about what was possible and opened their eyes
to new possibilities for using vehicle automation technology to improve
transit operations. That, of course, is one of the strongest reasons
for investing the effort to present such a demonstration.
efforts were considerable and involved extensive time spent away from
home by a team of more than a dozen PATH research and development engineers, working
under the leadership of Dr. Ching-Yao Chan including: Bénédicte Bougler, Fanping Bu, Susan Dickey, Bart Duncil, Anouck Girard, Adam Howell, Paul Kretz, Thang Lian, Joanne Lins, David Marco, David Nelson, Christopher Nowakowski, Daniel Schickele, Bongsob Song, Han-Shue Tan, and Elvin Vedar. Their work schedule was
governed by the limited availability of the I-15 HOV facility for testing
in preparation for the demonstration. All of the preparatory testing
needed to be conducted during the four weekends prior to the demonstration
(8 am to 8 pm each day) and during the weeknights in the two weeks immediately
before the demonstration (8 pm to midnight). With outstanding cooperation
and support from Caltrans District 11 and Division of Research and Innovation
(DRI) colleagues, extremely rapid progress was made during that final
month of preparations for the demonstration.